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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: dr.ph0b on July 17, 2004, 11:20:34 PM

Title: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 17, 2004, 11:20:34 PM
ok, i got sidetracked with a new toy, that i think some might find interesting. especially since its $14.99!! :)

RS part# 15-1228. it runs on 9v DC, and comes with a wall adapter that lists the output as 9v 100mA. not sure what the amp-hour rating is on a normal 9v alkaline, but i simply cut the adapter wire, slapped a 9v battery plug on it and connected a 9v alkaline to it and its running fine. im testing now, how long it will run off 1 9v alakaline. and grabbed another toy.. also $14.99..  the optical splitter in the bottom pic :) daisey chain JB3's?? :)


here are some pics:

(http://philzone.routeflap.net/digi-conv/PICT0044.JPG)
(http://philzone.routeflap.net/digi-conv/PICT0047.JPG)
(http://philzone.routeflap.net/digi-conv/PICT0049.JPG)
specs
(http://philzone.routeflap.net/digi-conv/PICT0053.JPG)
opti splitter
(http://philzone.routeflap.net/digi-conv/PICT0052.JPG)
Title: Re: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 18, 2004, 01:45:00 AM
ok, im up to the 4 hour mark recording coax in->optical out to jb3 with the 9v alkaline...
Title: Re: ratshack digital signal converter testing :)
Post by: save on July 18, 2004, 02:49:44 AM
been using the same converter from radio shack for a whille now.  only really use it to go optical > coax when transfering md for people.  worked great for me so far.
Title: Re: ratshack digital signal converter testing :)
Post by: caymanreview on July 18, 2004, 03:36:21 AM
those optical splitter can really screw with a jb3 recording

they work great with md decks i hear, but a jb3 is kinda picky and when you just split the light signal like that it causes problems with the jb3
Title: Re: ratshack digital signal converter testing :)
Post by: F.O.Bean on July 18, 2004, 07:24:28 AM
let us know bro, keep us posted :)
Title: Re: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 18, 2004, 12:57:58 PM
well its been powered on now for almost 16hours. been recording for about half that off the same 9v. :)
Title: Re: ratshack digital signal converter testing :)
Post by: Chris K on July 18, 2004, 01:06:38 PM
any tests for battery duration while recording, or wont it matter? are you passing a signal while testing how long the 9v will last?

again...keep us posted. i would like to use this going mod sbm-1 > jb3

great job!
Title: Re: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 18, 2004, 01:12:05 PM
yeah.. im recording to my jb3 so ill have official times based on how long its been on and how long its actually recorded.

btw, I use modsbm1->jb3 with the sony 7pin optical cable with flawless results. do you not have one of those cables?  i think sony has some for sale still
Title: Re: ratshack digital signal converter testing :)
Post by: Chris K on July 18, 2004, 01:16:02 PM
i bought  a used one, but it was busted, and confirmed as such by paul at pro digital. you can see the light on the output end but it is not passing signal either way. i got my money back for the cable, thankfully, and i have to return it to the seller

paul at pro-dig said they no longer make the sony cable, but there are a few old stock that already have the mini optical out built in. he said he can still get them for $85 (?)

i was contemplating getting a new cable, but if this rs optical dealie works for you, i may give it a whirl
Title: Re: ratshack digital signal converter testing :)
Post by: ashevillain on July 18, 2004, 01:56:44 PM
paul at pro-dig said they no longer make the sony cable, but there are a few old stock that already have the mini optical out built in. he said he can still get them for $85 (?)

Interesting b/c when I talked to him a couple months ago he said he couldn't get any more and referred me to Klay Anderson who advertised them on his website but also said he couldn't get them any more.
Title: Re: ratshack digital signal converter testing :)
Post by: Chris K on July 18, 2004, 02:00:44 PM
maybe paul thought you were talking about the 2 toslink original version, not the newer one that has the mini optical out connector

i was in paul shop when he told me he can still get them

i think i may get one, but this ratshack converter thing still is an option
Title: Re: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 18, 2004, 07:21:52 PM
ok.. well the battery finally gave out after being on for 20hours. i was recording for 8 of those hours. no glitches or anything even up to the point the battery died. i was expecting some pops when the battery got weaker in the end, but nope, it just cut off. im wondering how much more battery power it would use while recording than it would use while sitting idle? i know the optical light is beaming the whole time is plugged in. 

well i give it 2 thumbs up for some who would need it. price is amazing. very compact, and simple to add a 9V alkaline by cutting ac adapter plug off and putting on a 9v connector on it. (RS sells em in packs of 5)
Title: Re: ratshack digital signal converter testing :)
Post by: Simp-Dawg on July 18, 2004, 07:57:59 PM
what about bit-accuracy?
Title: Re: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 18, 2004, 08:39:27 PM
it only converting signal, not the data.
Title: Re: ratshack digital signal converter testing :)
Post by: hoobash on July 19, 2004, 12:51:51 PM
Does it send signal to the coax and optical ouputs at the same time?? I have the cheap sliver box convertor this looks like it could be a step up
Title: Re: ratshack digital signal converter testing :)
Post by: sleepypedro on July 19, 2004, 01:31:01 PM
i'm on the phone right now with paul, and sony does indeed still have the 7-pin / mini-toslink cable.  i've got one ordered.

wow, i might be back in action with the jb3!
Title: Re: ratshack digital signal converter testing :)
Post by: Chris K on July 19, 2004, 05:00:29 PM
still $85?

Title: Re: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 20, 2004, 02:19:04 AM
Does it send signal to the coax and optical ouputs at the same time?? I have the cheap sliver box convertor this looks like it could be a step up

yeppers. i have a coax input and it outputs to both optical and coax simultaneously
Title: Re: ratshack digital signal converter testing :)
Post by: F.O.Bean on July 20, 2004, 09:09:06 AM
it only converting signal, not the data.

isnt the signal technically data tho ???

so bit-perfectness would matter
Title: Re: ratshack digital signal converter testing :)
Post by: hoobash on July 20, 2004, 09:21:43 AM
Sold!!! I am pick one up

Does it send signal to the coax and optical ouputs at the same time?? I have the cheap sliver box convertor this looks like it could be a step up

yeppers. i have a coax input and it outputs to both optical and coax simultaneously
Title: Re: ratshack digital signal converter testing :)
Post by: hoobash on July 20, 2004, 09:22:52 AM
Has there been a issue with these things loosing data?? Its not like a has sample rate convertion

it only converting signal, not the data.

isnt the signal technically data tho ???

so bit-perfectness would matter
Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on July 20, 2004, 11:12:06 AM
Has there been a issue with these things loosing data??

That's what we're trying to find out.  With other digital format converters (DFCs), yes, users have encountered issues - dropped samples, introduction of artifacts, etc.

Its not like a has sample rate convertion

No, but the DFCs are built to convert a S/PDIF coax signal to optical.  However, virtually no manufacturer follows the S/PDIF standard.  Since the S/PDIF source and the DFC both may not follow the S/PDIF standard, the combination of the two non-standard S/PDIF specs may create a situation where the DFC has trouble converting the signal it's receiving because the signal falls near our outside it's specified tolerance.  The problems may appear readily and audibly in a short test.  The problems may not occur audibly initially, but perhaps reveal themselves over time.  Or the source device + DFC may have not problems at all.  We don't know, and I believe that's the point Bean is trying to make.

I haven't seen any mention by Dr. Phob that he's listened to the complete recorded WAVs (20+ hrs) to identify if they contain audible dropped samples or artifacts, nor have I seen indication he's checked them for bit accuracy against a control file.  IME, it's much easier - and more authoritative - to verify bit-accuracy than casually listen to the WAVs played back.  If the DFC proves bit-accurate under controlled conditions, I would hold a high degree of confidence using it in the field.  If it does not prove bit-accurate, I would have very little confidence using the DFC in the field.  If it is not bit-accurate, but the DFC doesn't present audible dropped-samples or artifacts under a short duration of testing, I still would have very low confidence - if it isn't bit-accurate, then something is not functioning properly in the source signal > DFC > target recorder chain and IMO this something will eventually manifest itself in audible artifacts or dropped samples.

Given history of people trying various DFCs and encountering trouble with them, I wouldn't trust this particular DFC (or any other one, for that matter) until I had a chance to verify it's bit-accuracy.  This is exactly why I tested the Hosa ODL-312 before using it widely in the field.
Title: Re: ratshack digital signal converter testing :)
Post by: F.O.Bean on July 20, 2004, 11:26:58 AM
great post brian :)
Title: Re: ratshack digital signal converter testing :)
Post by: Lil Kim Jong-Il on July 20, 2004, 11:53:00 AM
However, virtually no manufacturer follows the S/PDIF standard. 

I assume you meant the electrical interface?  Can you elaborate?

Most of these cheap little DFCs are just a TTL buffer with optical coupler on either side and pulse transformers for the coax interface.  You'd have to really fuck it up to fall outside of spec with the signal at the connector.
Title: Re: ratshack digital signal converter testing :)
Post by: bhtoque on July 20, 2004, 01:33:28 PM
those optical splitter can really screw with a jb3 recording

they work great with md decks i hear, but a jb3 is kinda picky and when you just split the light signal like that it causes problems with the jb3

I can't get my jb3 to work at all through one of those splitters, but the converter is sweet.

I've listened to about 15 hours of shows I've done through it to my md (which I use as backup) and have had no audible problems. I run my jb3 off the ua-5's optical and the converter off the coax so I don't run either deck analog.

JAson
Title: Re: ratshack digital signal converter testing :)
Post by: hoobash on July 20, 2004, 02:22:03 PM
So who is going to test this thing?
Title: Re: ratshack digital signal converter testing :)
Post by: Brian on July 20, 2004, 02:24:07 PM
it would appear Dr Phob has stepped up to the plate. we haven't heard from him today though so who knows how his in house test went yesterday as far as bit accuracy.
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on July 20, 2004, 02:37:13 PM
Can't wait to hear the results on the bit-accuracy....if it is that will be a huge find and cheap alternative.   Even if not, I may just pick one up for patchers anyways.
Title: Re: ratshack digital signal converter testing :)
Post by: Cooker on July 20, 2004, 08:00:12 PM
well i have two of those splitters, and never got them to work right with the jb3 or SBM-1 > Splitter > PCM-M1 and Sharp 831 MD

only time i got them to work were going ultramatch > Pioneer MD and Pioneer Standalone

Title: Re: ratshack digital signal converter testing :)
Post by: hoobash on July 20, 2004, 09:53:07 PM
I picked one of these up today. I has to be as good as the little sliver box i have
Title: Re: ratshack digital signal converter testing :)
Post by: goose on July 20, 2004, 10:13:49 PM
i'm on the phone right now with paul, and sony does indeed still have the 7-pin / mini-toslink cable.  i've got one ordered. (snip)

These mini-toslink 7 pin cables are still available, I ordered one from B&H two weeks ago, they have them in stock as well.  I think the part number is POCDA12SP or something like that - the "SP" at the end indicates the mini-toslink in and out.
Title: Re: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 21, 2004, 03:13:57 AM
i'm on the phone right now with paul, and sony does indeed still have the 7-pin / mini-toslink cable.  i've got one ordered. (snip)

These mini-toslink 7 pin cables are still available, I ordered one from B&H two weeks ago, they have them in stock as well.  I think the part number is POCDA12SP or something like that - the "SP" at the end indicates the mini-toslink in and out.

u can order them direct from sony too:

http://servicesales.sel.sony.com/web/viewItemDetail.do?operation=getItemDetail&itemID=24212&category=8&categoryName=Cable
Title: Re: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 21, 2004, 03:18:19 AM

I haven't seen any mention by Dr. Phob that he's listened to the complete recorded WAVs (20+ hrs) to identify if they contain audible dropped samples or artifacts, nor have I seen indication he's checked them for bit accuracy against a control file.  IME, it's much easier - and more authoritative - to verify bit-accuracy than casually listen to the WAVs played back. 

sorry sometimes work keeps me busy from checking back on all these forums :(  damn work

anyway, how would i _test_ for bit-accuracy?  does wavlab have a feature?
Title: Re: ratshack digital signal converter testing :)
Post by: F.O.Bean on July 21, 2004, 12:06:31 PM
youd have to compare wavs in EAC or something :)
Title: Re: ratshack digital signal converter testing :)
Post by: Brian on July 21, 2004, 12:50:51 PM
youd have to compare wavs in EAC or something :)

;D +T
Title: Re: ratshack digital signal converter testing :)
Post by: F.O.Bean on July 21, 2004, 12:52:28 PM
+T backatcha bud :)
Title: Re: ratshack digital signal converter testing :)
Post by: dnsacks on July 21, 2004, 02:15:31 PM
Testing for bit-accuracy --

Actually, open both wavs up in soundforge, find and mark a common sample point a few seconds after the very beginning of the wavs.  Select and copy one of the wavs from the common sample point forward.

then, go to the other wave and instruct soundforge to mix the inverse (invert the wav? -- don't have soundforge here) of one wav with the other.

The result, if both are identical will be a ruler-flat line (zero db) for the lenght of the entire mixed wave (since music plus the inverse of the music would be silence).  Any dropped sample, etc. would cause a spike in the mixed wave, or "music" to appear along the wave (albeit strange sounding distored music)

hope this helps
Title: Re: ratshack digital signal converter testing :)
Post by: sleepypedro on July 22, 2004, 11:47:06 AM
alternately you could just md5sum both wavs, and provided you started and ended your test clips on the same samples AND the device in question is bitperfect AND both grabs were read with no errors, you'll get identical checksums
Title: Re: ratshack digital signal converter testing :)
Post by: Lil Kim Jong-Il on July 22, 2004, 02:06:18 PM
Instead of md5 (you better be exact on start and stop sample) and wave inversion sum (same problem), I'd go with the EAC suggestion if your comparing 16bit samples.  The EAC results actually tell you the problem - missing sample, duplicate block, etc.  Both the other will work, but it's up to you to perfectly time align the areas of interest.
Title: Re: ratshack digital signal converter testing :)
Post by: cwfen on July 26, 2004, 06:32:00 PM
Updates?
Title: Re: ratshack digital signal converter testing :)
Post by: dr.ph0b on July 29, 2004, 03:00:18 AM
sorry.. been getting killed with work.. ill try to do something this weekend
Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on July 29, 2004, 11:48:34 AM
However, virtually no manufacturer follows the S/PDIF standard. 

I assume you meant the electrical interface?  Can you elaborate?

Yeah, I should've clarified - electrical interface.  I should also note that variances in the S/PDIF electrical interface causing DFC problems is merely conjecture on my part as I haven't done the testing to determine the root cause of the problems with some DFCs.
Title: Re: ratshack digital signal converter testing :)
Post by: cwfen on August 07, 2004, 01:02:50 AM
...any results on the bit-for-bit testing?
Title: Re: ratshack digital signal converter testing :)
Post by: johnw on September 03, 2004, 11:23:26 PM
What was the final word on this?
Title: Re: ratshack digital signal converter testing :)
Post by: hoobash on September 06, 2004, 09:31:45 AM
I got one. I am not sure how to test. Maybe I should go back and read the thread again?
Title: Re: ratshack digital signal converter testing :)
Post by: bhtoque on September 07, 2004, 12:14:37 AM
Ok, I figured I'd do the testing on this, and I've opened another can of worms.

Here's what I did.

I recorded a cd track from my Sony C701ES>optical cable>jb3 (did this twice) and
Sony C701ES>optical cable>ratshack converter>optical cable>jb3

Synchro was on on the jb3 so the files should all have the same starting point.

I then used cool edit pro to make all 3 files the same length. The file size matches too. If I invert-mix any of the 3 they cancel themselves out like they should, but the inverse of one does not cancel out either of the other 2.

If I put the two straight cd>jb3 files in multitrack view they match up.

I was willing to accept that the rs box was not bit perfect, but shouldn't the two cd>jb3 files match? Does this mean the jb3 is not bit-perfect? ???

I can upload the files if someone has space.

JAson
Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on September 07, 2004, 07:46:00 AM
Try EACs WAV Compare function with the files you have.

Theoretically the two CD > JB3 files should match, but that assumes [1] the C701ES doesn't have a resampling output and [2] provides a signal to the JB3 that the JB3 likes, so to speak.

Also, I don't see in your chain where you're actually converting the digital signal with the RS box:  C701ES > optical > RS box > optical > JB3.  Can you run C701ES > coax > RS box > optical > JB3?
Title: Re: ratshack digital signal converter testing :)
Post by: bhtoque on September 07, 2004, 02:21:27 PM
Try EACs WAV Compare function with the files you have.

Theoretically the two CD > JB3 files should match, but that assumes [1] the C701ES doesn't have a resampling output and [2] provides a signal to the JB3 that the JB3 likes, so to speak.

Also, I don't see in your chain where you're actually converting the digital signal with the RS box:  C701ES > optical > RS box > optical > JB3.  Can you run C701ES > coax > RS box > optical > JB3?

The rs box takes in either and puts out both, so I doubt it is just a pass through for the incoming format. Unfortunately I don't have anything that will put out coax besides my ua-5.

To make things worse I can't run EAC on my xp system. EAC reboots the pc as soon as I try to launch it. I've spent several hours troubleshooting it, changing aspi layers etc and have had no luck.

JAson
Title: Re: ratshack digital signal converter testing :)
Post by: rustoleum on September 15, 2004, 10:41:54 AM
I picked one of these up and have begun testing it and wanted to share my results so far.  After jumping through some hoops to get a reliable test setup (see this thread for the gory details: http://www.taperssection.com/yabbse/index.php?topic=26297.msg329324#msg329324) I have managed to have some success with this box.

The final phase 1 test setup consisted of a one minute long sine curve generated by WaveLab, output to a Sony D100 via a Zoltrix Nightingale  coax output.  The sine curve ran from 44.1 Hz to about 20,000 Hz and back down.  I then ran the signal back out of the D100 into both the Coax-In of the zoltrix (as a control source) and then into the Rat Shack digital convertor's coax input -> toslink output -> toslink cable -> toslink digital input on the zoltrix.  The samples once trimmed to the same start and end sample matched perfectly in both WaveLab4's file comparison and EAC's Wav compare tools.

Pretty simple test, so far, but good results indicating the convertor is indeed bit accurate.

My next test is conisting of more Sine curves, however I've added a lot more variation.  Ex - I'm using one sine curve spanning 16hz to 20,000 and back down in the left channel and in the right channel I'm using a curve that begins at about 700 Hz, crawls up to 20,000 Hz, and then sweeps down from 20Khz to 44 Hz.  After 10 seconds the curves repeat but change channels.  The 20 second pattern then repeats for an hour.

I'm dumping the new hour long test signal to DAT as I type and will then run it through the convertor and see what happens.  more to come...

Rusty

Title: Re: ratshack digital signal converter testing :)
Post by: MattD on September 15, 2004, 11:14:00 AM
Why the sines? White noise will tell you what you need to know here.
Title: Re: ratshack digital signal converter testing :)
Post by: rustoleum on September 15, 2004, 11:18:15 AM
I wanted to force the test signal to utilize the majority of the frequency spectrum available to DAT.  Additionally, I've seen threads here involving channel swap in similar situations so that's why I forced the channels to alternate... I want to know if that type of problem is happening and a constant signal that does not fluctuate in some way would not allow me to notice a change like that.

Is there a reason I should use white noise instead of the sine curves or are you just mentioning it since it would be less work, yet still give us an idea of the accuracy?  Thanks!
Title: Re: ratshack digital signal converter testing :)
Post by: MattD on September 15, 2004, 01:36:18 PM
I mentioned mostly from the "less work" perspective. It covers your entire frequency spectrum and provides channel separation (if you use a different signal for each channel). Generate a good length of noise in a file. Play back the file through the device to DAT, transfer DAT, chop leader/trailer on DAT, compare files.
Title: Re: ratshack digital signal converter testing :)
Post by: rustoleum on September 17, 2004, 11:50:24 AM
I'm about ready to call this thing bit-accurate.  I've put about 2.5 hours of audio through it and gotten 100% of the same bits put through the coax-in of the zoltrix.

Unfortunately, I have also gotten about 2 hours that were 99.9544% accurate.  However, although I can't be 100% certain at  this point,  I am willing to attribute this to the Zoltrix Nightingale and/or the DAT deck as several transfers of the same 'offending' WAV through just the coax-in also resulted in a similar accuracy.

I still have yet to hook it up to the MiniMe and do a comparison feeding it that way, but once I do that I will presumably have a better idea if the DAT deck was the culprit.  For the moment, I would venture to say that this thing is field ready.

Also - please note that in the .0466% of the time where problems arose, they were inaudible - The samples were not dropped, but rather slightly altered (I can post a pic or two if desired).  Listening did not reveal a problem, but rather bit-for-bit file comparisons.  So, you guys using the Hosa ODLs and saying "I haven't heard any problems" should know that just because you can't hear it, doesn't mean it's bit-perfect.  That said, I do realize testing similar to what I am doing has been performed on the Hosas... I'm just saying this because in addition to that there seems to be a lot of stock put into what our ears can pick up which doesn't necessarily proove a thing.


Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on September 17, 2004, 12:03:28 PM
Thanks for your testing efforts!

I vaguely recall Jamie Lutch testing the C02 and sometimes having to run through 10-20 hrs before encountering problems.  Just suggesting that a couple hours testing may not be enough to decide one way or the other.

And if your problems appear on both the control WAV and the DFC WAV then it sounds like you're right - the Zoltrix and/or DAT may have issues.  I'm real curious to see the results once you fire up the MMe and get some additional testing hours completed.

FWIW, I tested the ODL-312 ~100+ hrs and it was flawless, totally bit-perfect - after ruling out a seemingly random channel-swapping problem I seem to have in my EgoSys Waveterminal 2496 and/or recording software.  I don't know of anyone who's tested the -276.  And you're absolutely right - just because you can't hear it doesn't mean it's bit-perfect.  Though for some people that's good enough.  :)
Title: Re: ratshack digital signal converter testing :)
Post by: rustoleum on September 17, 2004, 03:17:20 PM
I definately want to do more testing but unfortunately need to change up my process to determine if the zoltrix or DAT deck was causing me troubles.

The next round of testing will consist of sending audio into the MiniMe out to my lappy via USB and out to my standalone CD-burner via Coax -> Convertor -> Optical In.  If I'm able to get several successful hours out of this I'll probably go back to using the Zoltrix in an effort to determine where my original flaws were coming from. 

And, as long as I'm posting, here's an example of one of the .0456%  of my transfers that failed verification.  The difference in samples is pretty minor, but it ain't an exact copy.

Title: Re: ratshack digital signal converter testing :)
Post by: dklein on September 17, 2004, 06:08:49 PM
fwiw, I think I did about 20 or 30 hours of testing to verify UA-5 > JB3 bit accuracy http://ca.geocities.com/dkleined@rogers.com/audio/bit/BitAccuracy.htm
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on September 23, 2004, 12:32:09 AM
I just picked one of these up :)
Hope I can help out somewhat on the testing.   I've got a UA-5 and 2 JB3's...would a viable test be to run one JB3 optical out of the UA-5 and another JB3 out of the coaxial with the Ratshack box converted to optical into the other JB3.   Then compare the 2 files from the same starting point?   Has it been verified that the UA-5 has exactly the same bits coming out of the optical and coax jacks?   If so, then I think this should be a good test.
Title: Re: ratshack digital signal converter testing :)
Post by: rustoleum on September 24, 2004, 01:29:20 PM
I can't comment on the UA5 outputs, but if they are indeed the same bits then this would be a great test.
Title: Re: ratshack digital signal converter testing :)
Post by: bhtoque on September 24, 2004, 04:10:48 PM
I just picked one of these up :)
Hope I can help out somewhat on the testing.   I've got a UA-5 and 2 JB3's...would a viable test be to run one JB3 optical out of the UA-5 and another JB3 out of the coaxial with the Ratshack box converted to optical into the other JB3.   Then compare the 2 files from the same starting point?   Has it been verified that the UA-5 has exactly the same bits coming out of the optical and coax jacks?   If so, then I think this should be a good test.

I doubt he has run a test on it, but Doug Oade probably knows the signal path in that thing better than anybody else in the community. Shoot him and e-mail, I'm sure he'd help.

JAson
Title: Re: ratshack digital signal converter testing :)
Post by: dklein on September 24, 2004, 05:44:15 PM
 I've got a UA-5 and 2 JB3's...would a viable test be to run one JB3 optical out of the UA-5 and another JB3 out of the coaxial with the Ratshack box converted to optical into the other JB3.   Then compare the 2 files from the same starting point?   Has it been verified that the UA-5 has exactly the same bits coming out of the optical and coax jacks?   If so, then I think this should be a good test.
the coax and optical are separately buffered but driven from the same source - they are the same.  You can also compare the JB3 to a USB recording if you've got that going glitch free.
Title: Re: ratshack digital signal converter testing :)
Post by: johnw on September 24, 2004, 06:06:00 PM
That's weird because I have done that and the levels over USB were lower by a few decibals than the same file recorded by JB3 and played back through Soundforge. Never did a bit test because I was just trying to get my SUV calibrated.
Title: Re: ratshack digital signal converter testing :)
Post by: dklein on September 24, 2004, 08:44:11 PM
That's weird because I have done that and the levels over USB were lower by a few decibals than the same file recorded by JB3 and played back through Soundforge. Never did a bit test because I was just trying to get my SUV calibrated.

very weird indeed.  actually...shouldn't be possible.  And I can't come up with any reason why it would happen unless you're talking about the SUV measuring differently.  The wave files produced from USB and JB3 should be the same.  The SUV levels will be affected by the monitor function on the UA-5 because the SUV is driven from the analog output and gets messed up when the monitor button is on.  You actually get a double signal, slightly delayed.
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on September 25, 2004, 05:09:59 AM
Sounds good...well if they turn out to be bit for bit perfect then we definitely know the coax and optical out of the UA-5 are equal for sure too ;p

Anyways, I just started a quick initial test...will be a 1 hour test.   I even started the JB3's at the same time and it is kinda funny to listen to the JB3's you can hear them both make HD writes at the same time in sync too ;p
Popped on the phantom power to the mics 5 seconds into the recording and both are off and running.   

Looks like with the handy dandy "File Comparer" tool in Wavelab it should be rather easy to compare.   Will post results from initial test.   Keeping fingers crossed ;)
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on September 25, 2004, 06:35:15 AM
I think it came back perfect.  Wavelab gives me the message "The two files have a different size, but the shorter one is exactly equal to the start of the longer one."   I think it got a little funky at the end one channel cut out sooner than the other on one of the recordings.   So I am gonna lop off a few samples off of both and retry ;)
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on September 25, 2004, 06:58:37 AM
Yippie!   Yeah, just had to lop off one extra sample at the end from one file....dunno quite how that happened like that(probably due to the fact that I just cut power on the UA-5 to create the empty space at the end).   Anyways now I get "The two files ar exactly equal!"

So a very good sign the first test of 1 hour passed with flying colors.   I hope to do many many more hours of testing to before we come to the conclusion it is indeed bit perfect.  But this first test passed and if results stick it confirms 3 things:
A) Ratshack Converter is bit-perfect
B) UA-5 outputs coax and optical are indeed exactly the same
C) One of my JB3's was completely empty just formatted and the other one was 95% full...so no problems at all on the near full one with regards to writing to a near full disk.  I had an hour and a half left on it and used up an hour of that.   So only a half hour left(295 MB out of 19056 MB left).
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on September 25, 2004, 12:42:56 PM
Ahh woke up this morning and did another test.
I forgot to mention the first test was using AC power, and done at 44.1 khz.
This time I hooked up my 9.6 V RC battery pack to the Ratshack converter and did a quick new test(also at 44.1 khz) and it passed 100% again :)
Title: Re: ratshack digital signal converter testing :)
Post by: johnw on September 25, 2004, 12:48:43 PM
That's weird because I have done that and the levels over USB were lower by a few decibals than the same file recorded by JB3 and played back through Soundforge. Never did a bit test because I was just trying to get my SUV calibrated.

very weird indeed.  actually...shouldn't be possible.  And I can't come up with any reason why it would happen unless you're talking about the SUV measuring differently.  The wave files produced from USB and JB3 should be the same.  The SUV levels will be affected by the monitor function on the UA-5 because the SUV is driven from the analog output and gets messed up when the monitor button is on.  You actually get a double signal, slightly delayed.

I hooked up my laptop and recorded a test tone with Soundforge 5. I was trying to get the levels set with SF5 since that is what I use to edit wav files anyway. Without touching any settings on the UA5, I unplugged the laptop and plugged in the JB3, recorded the test tone, transferred the file to the laptop and opened the file in SF5 to make sure the levels were set. To my surprise they were about 3 dB louder in both channels. If I get time today, I will repeat this with simultaneous recording to both laptop and JB3. I agree that it shouldn't be possible, so maybe I'm remembering this wrong, but it stuck with me because I thought it was weird at the time.
Title: Re: ratshack digital signal converter testing :)
Post by: dklein on September 25, 2004, 04:04:21 PM
Is everything set to 16/44.1 and is the adv switch on the back of the UA-5 off?
Title: Re: ratshack digital signal converter testing :)
Post by: bluegrass_brad on September 26, 2004, 01:01:52 PM
I actually found a converter very similar to the Ratshack one except it is only coax > optical.  Found it on ebay.  It was the same size and price as the Ratshack box.  The best thing about this one is it runs on 6v.  I'm hoping that it passes bitperfect testing, because I run an SBM-1 (coax mod) and it would be sweet to be able to just run it off the battery im powering the SBM-1 with.
here is a link to one on there right now....

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=14968&item=5721893974&rd=1
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on September 26, 2004, 03:01:05 PM
I had enough confidence in it so I used it for the Jack Johnson, G Love, Frankenreiter show at the Gorge last night.   I was actually barrowing another person's rig who had a SBM-1 but I wanted to use my JB3 rather than the DAT with it so I ran the Ratshack box off my 9.6 V battery I normally use for my UA-5(exact same plug even...just had to switch polarity of course).
Title: Re: ratshack digital signal converter testing :)
Post by: caymanreview on September 26, 2004, 03:07:31 PM
I actually found a converter very similar to the Ratshack one except it is only coax > optical.  Found it on ebay.  It was the same size and price as the Ratshack box.  The best thing about this one is it runs on 6v.  I'm hoping that it passes bitperfect testing, because I run an SBM-1 (coax mod) and it would be sweet to be able to just run it off the battery im powering the SBM-1 with.
here is a link to one on there right now....

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=14968&item=5721893974&rd=1

i had one of those for awhile, i didnt notice any noticeable glitches with it. but i never tested its bit-perfectness

one member here said he had tested it, and it passed, but as always YMMV
Title: Re: ratshack digital signal converter testing :)
Post by: Cooker on October 05, 2004, 11:46:33 AM
i ran the ratshack convertor friday night without incident. i was worried that the 9V duracell wouldn't last a whole show but it certainly did.  i ran mics > V3 > split coax >  Convertor > JB3 and 
                                                                  >   Luvean's M1

i haven't done any bit accuracy tests yet but the global file analysis tool in wavelab didn't turn up any errors.

i don't plan on using this convertor much but it sure was nice to have when Hatgis' V3 was just sitting in his bag, not being used at all....

felt like one of those kids with a $5,000 stereo in a 91 cavalier, running Oktavas into it :)

next step is wiring it to my 9.6v's

Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on October 05, 2004, 01:22:51 PM
felt like one of those kids with a $5,000 stereo in a 91 cavalier, running Oktavas into it :)

MC012s?  How'd it turn out?  I bet the MC012s sound awfully good in front of the V3.
Title: Re: ratshack digital signal converter testing :)
Post by: nic on October 05, 2004, 04:21:19 PM
felt like one of those kids with a $5,000 stereo in a 91 cavalier, running Oktavas into it :)

MC012s?  How'd it turn out?  I bet the MC012s sound awfully good in front of the V3.

unfortunately, it was in probably the worst sounding room imagineable(McDonough Gym @ Georgetown U) and we were far from the "sweet spot"...actuallyl, there was no "sweet spot"
we were going to move the rig at setbreak, but there was no setbreak
recording came out better than it sounded there, so thats a plus.

in a better room, the Octavas>V3 would have sounded pretty sweet
Title: Re: ratshack digital signal converter testing :)
Post by: F.O.Bean on October 20, 2004, 09:24:16 PM
any word on the bit-perfect tests ???
Title: Re: ratshack digital signal converter testing :)
Post by: hexyjones on October 20, 2004, 09:46:14 PM
any word on the bit-perfect tests ???

I think they're in there, bean...seems like there was a rally on this thread a few weeks ago...dial back a few pages...

It seemed to pass the tests as I recall...
Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on October 21, 2004, 03:44:55 AM
any word on the bit-perfect tests ???

There's a test or two mentioned in the thread, but personally not thorough enough to convince me.  I'm skeptical by nature, though.  :)
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on October 21, 2004, 04:27:19 AM
Just a heads up on what could be some bad news.  I used the Ratshack converter when barrowing another person's rig (Schoeps MK4s -> Nbox ->Oade mod SBM-1) and all my recordings completely bombed at the Gorge show.  They were rittled with small clicks/pops throughout the recordings for all 3 bands I taped.   So I am not sure if it is an issue with the SBM-1 signal, or the JB3 receiving it or the Ratshack box but that combo of 3 equaled disaster.   I didn't have any headphones on my at the time so I thought I was golden since I was getting levels perfectly fine on my JB3.   Got home and listened to my recordings to come back with these results.   I thought it could have been a cables issue (like with the optical or coax) but I checked all the cables and they were all 100% working order.
Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on October 21, 2004, 05:06:00 AM
There's a test or two mentioned in the thread, but personally not thorough enough to convince me.  I'm skeptical by nature, though.  :)

This question came up on the yahoo NJB3 group, too. I skimmed back through the thread and came up with the following test results people have reported:

Chris V - 1 hr flawless
Rustoleum - 2.5 hrs flawless, 2 hrs flawed (cause of flaws still
unknown, but may be related to soundcard)

Have either of you performed additional testing?  Anyone else?
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on October 21, 2004, 05:21:29 AM
I haven't done any more testing since it apparently failed miserably in the field with the SBM-1 and JB3 which is the only thing I was gonna really use it for.   But with the UA-5 it works like a champ ;p

Just curious, has anyone used the Hosa converter in combo with the SBM-1 into a JB3 with success?
Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on October 21, 2004, 05:30:53 AM
Thanks for the update, Chris.  And WTF are you doing awake at 5:21AM?

I vaguely recall someone using one of the Hosa boxes successfully with the SBM-1, but I'm not certain.  Hopefully someone will chime in.
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on October 21, 2004, 05:32:25 AM
West Coast...2:30 AM :)   Although that is not too much better lol.   Going to bed soon here ;)
Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on October 21, 2004, 05:44:23 AM
West Coast...2:30 AM :)   Although that is not too much better lol.   Going to bed soon here ;)

lol  Alright,I'll rephrase:  WTF are you still doing awake at 2:30am?!?  Posting on TS is a bit wacky when on GMT.  I keep expecting people to respond to my morning (for me) posts, only to have to wait 5+ hrs til people start waking up back home.

FWIW, as some have declared the RS DFC bit-perfect on the NJB3 Yahoo group, I've asked if anyone has performed further RS DFC testing over there - I suspect not (though Mike Wren maybe has).  If I find anything out I'll cross-post here.
Title: Re: ratshack digital signal converter testing :)
Post by: hexyjones on October 21, 2004, 08:06:48 AM
Just a heads up on what could be some bad news.  I used the Ratshack converter when barrowing another person's rig (Schoeps MK4s -> Nbox ->Oade mod SBM-1) and all my recordings completely bombed at the Gorge show.  They were rittled with small clicks/pops throughout the recordings for all 3 bands I taped.   So I am not sure if it is an issue with the SBM-1 signal, or the JB3 receiving it or the Ratshack box but that combo of 3 equaled disaster.   I didn't have any headphones on my at the time so I thought I was golden since I was getting levels perfectly fine on my JB3.   Got home and listened to my recordings to come back with these results.   I thought it could have been a cables issue (like with the optical or coax) but I checked all the cables and they were all 100% working order.

I have had the same thing happen...using only the analog ins...

The clicks I have sound like CD skips...like 5-6 clicks in a row...and then fine...no pattern...intermittent...

Highly possible that these artifacts would be undetectable with headphones...

Were you near any cellphones...? Large power wires? Some have theorized that the JB3 is poorly shielded from RF...
Title: Re: ratshack digital signal converter testing :)
Post by: dklein on October 21, 2004, 03:20:36 PM
It may be difficult to pronounce a piece of gear 'bit perfect' without considering what comes before and after.  Most of these devices are way to simple to not be bit perfect if they're getting the right signal voltage.  But when the signal voltage doesn't match the design, errors can occur.  Some designs may be more tolerant of 'out of spec' signal than others.  It wouldn't be surprising if most were flaky when receiving coax digital from some Sony units becuase of their unusual voltage. 

You could accomodate this in the converter design (change the threshold for what constitutes an 'on'). 

Interesting that the digital output level of the mic2496 is switchable to match your input device.  Too bad it's from Coresound.
Title: Re: ratshack digital signal converter testing :)
Post by: rustoleum on October 21, 2004, 03:52:27 PM
Haven't had a chance to do anything new, unfortunately.  Still have plans of continuing with it, but time has not been on my side.  I will definately post here when I have anything new.
Title: Re: ratshack digital signal converter testing :)
Post by: Brian Skalinder on October 21, 2004, 03:59:46 PM
It may be difficult to pronounce a piece of gear 'bit perfect' without considering what comes before and after.

Great point, David.  And in light of it, I'll amend:  I still haven't seen enough evidence suggesting the RS DFC is bit-perfect in *any* gear combination.
Title: Re: ratshack digital signal converter testing :)
Post by: F.O.Bean on October 21, 2004, 06:40:21 PM
my thoughts exactly brian, 2.5 hrs isnt enuf to tell anything, maybe like 40-100 hrs :P

i bet you could fed the hosa anything and it will shoot a bit-perfect signal, it must have the correct voltage as said.
Title: Re: ratshack digital signal converter testing :)
Post by: pfife on January 07, 2005, 08:13:26 PM
FYI- these are discontinued by RS - the store by my house still had one in, so if you are thinking about this as an option, better go now!
Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on January 07, 2005, 11:06:30 PM
Yep, they were all gone from every local store around here except for one which was a display model I snagged.
Title: Re: ratshack digital signal converter testing :)
Post by: pfife on January 10, 2005, 07:54:09 AM
Yep, they were all gone from every local store around here except for one which was a display model I snagged.

Have you run it yet?   IF so, how are your results?  I should be getting my sbm-1 soon, so I'll let you know how my results are.  Has anyone found out whether this sucka is bit perfect or not?

FWIW - The dude at my local radio shack told me they have 4 in stock - I bought 1, so there are three - if anyone is interested, I can try to score one up and ship it out if you so desire, for cost - no profit by me.    I don't think they'll sell - the computer told him he had 4 of them, but it took him 5 minutes to find one, and it was buried... don't think anyone is looking to purchase them.

Title: Re: ratshack digital signal converter testing :)
Post by: ChrisV on January 10, 2005, 06:14:55 PM
Yeah, I posted results somewhere on this big thread ;p

It worked great with the UA-5 and I did find it to be bitperfect when using it to convert coax to optical(didn't test converting optical to coax).

It completely bombed when using it on a mod SBM-1 I barrowed though.   No need to check to see if it was bitperfect on that because the recordings were littered with little skips and jumps throughout.    Lemme know if you can ever get it to work w/ that because that was my main purpose I bought one in the first place so I could use my JB3 when barrowing another taper's rig.
Title: Re: ratshack digital signal converter testing :)
Post by: pfife on January 10, 2005, 09:02:07 PM
It completely bombed when using it on a mod SBM-1 I barrowed though.   No need to check to see if it was bitperfect on that because the recordings were littered with little skips and jumps throughout.    Lemme know if you can ever get it to work w/ that because that was my main purpose I bought one in the first place so I could use my JB3 when barrowing another taper's rig.

I am finding the same thing right now.  I am wondering if it is cause I pushed 48Khz through it.  Maybe it'll work with 44.1?

Title: Re: ratshack digital signal converter testing :)
Post by: pfife on January 11, 2005, 07:53:18 AM
Even worse results over 44.1Khz.  On to something else for this connection...
 :(
Title: Re: ratshack digital signal converter testing :)
Post by: Patrick on December 05, 2005, 04:43:54 PM
Bump.  I'm at ratshack right now and they have them on clearance for $10.  Should I get it? 
Title: Re: ratshack digital signal converter testing :)
Post by: bluegrass_brad on December 05, 2005, 04:54:37 PM
No, it is a POS.
Title: Re: ratshack digital signal converter testing :)
Post by: Roving Sign on December 05, 2005, 04:58:13 PM
Bump.  I'm at ratshack right now and they have them on clearance for $10.  Should I get it? 

A quick study of this thread gives one the idea that the SBM1 combo might not work...probably due to Sony's odd SPDIF implementation

But maybe a good backup for the HOSA/CO2 devices everyone uses...for 10 bucks you might be glad you had it...
Title: Re: ratshack digital signal converter testing :)
Post by: bluegrass_brad on December 05, 2005, 05:02:28 PM
I used one with an SBM-1 ( as was mentioned before, introduced pops/clicks, etc).  then used one to patch out of a P1 and a D8 and had the same problems.  I personally wouldnt use one due to my experiances with it. I never got a successful attempt with it (tried 5 or 6 times).  of course as always YMMV