Topic: Microtrack mods?

[udovdh]

Hello,

Who is doing MT mods?
Doug Oade doesn't do them anymore.
Who does a few magical tricks to the MT hardware?

Udo

[cybermansrev]

I don't think Oade ever did MT mods for the public he only played around with his own one.

However I'd agree I'm surprised no one is doing the mod Oade described, having the 1/8" socket modded to avoid the inbuilt gain and to reduce noise. Altough maybe there's  no interest in doing MT mods as people have their hands full with AKG actives and modding the R4. Plus I have the suspicion many people have their fingers crossed the R9 is going to be a cheap 24 bit recording solution with none of the MT's problems and that the MT's will go the way of 8-tracks.

[udovdh]

I would like to lower the ever present gain somewhat (by 6-8 dB?).
Maybe change the signal path so 1/8" and dual 1/4" do the same?
Maybe install a slightkly bigger Li-Ion pack? (see thread about battery mod)

It's no rocket science. With some research, I could point out the resistors that need change. (there's pics, we know the opamps...)
Just someone with SMD-skills and some business sense?

[udovdh]

Plus I have the suspicion many people have their fingers crossed the R9 is going to be a cheap 24 bit recording solution with none of the MT's problems and that the MT's will go the way of 8-tracks.

Did anyone review the R9 yet?
What is so much different and/or better/worse?

[drewloo]

Plus I have the suspicion many people have their fingers crossed the R9 is going to be a cheap 24 bit recording solution with none of the MT's problems and that the MT's will go the way of 8-tracks.

Did anyone review the R9 yet?
What is so much different and/or better/worse?

I think a lot of people here are betting that the R-9 will be less problematic than the MT, most likely based on Edirol's track record w/ the R-1, R-4, and UA-5. 

[cybermansrev]

It's no rocket science. With some research, I could point out the resistors that need change. (there's pics, we know the opamps...)

I would not describe myself as anything other than a bodger but I've opened my own MT to poke around the boards and despite knowing the pin outs of the opamps I still couldn't be certain of the resistors in the feedback loop to give the gain. Personally I would prefer to completely bypass the opamp and go straight to the ADC if possible, any rocket scientist out there going to give anyclues?

Just someone with SMD-skills and some business sense?

I think that "business sense" may be the biggest stumbling point, despite many on TS having MT's I doubt there would be a huge market for this very fiddly work, not to mention needing to charge enough to cover any "accidents" that may occur doing this kind of work.
It would also appear that many people are just using the MT as a bit-bucket so line input mods really wouldn't interest them.
I really think a solution to this is more likely to come from people tinkering around rather than those who could sell on their expertise. After all Oade has decided not to sell this mod and I think from previous posts Bussman planned on doing something but ended up selling his MT to concentrate on the R4.

Of course the other factor is M-Audio may release a revised version MT2? since I already think they have altered the component design without telling anyone.

Maybe install a slightkly bigger Li-Ion pack? (see thread about battery mod)

I think this is the most plausable mod at the minute since bigger mAh batteries are coming along all the time with smaller form factors for other devices like the ipod, so eventually we'll get one to fit even if it means removing the ?voltage regulation circuit on the original battery.

[udovdh]

M-Audio did change the design of the MT?
How can I tell?

[cybermansrev]

M-Audio did change the design of the MT?
How can I tell?

One of the problems with the MT info on TS is how fragmented it is. In your posting about battery mods http://taperssection.com/index.php?topic=59809.msg790146#msg790146 tooldvn linked to his MT internal pictures http://taperssection.com/index.php?topic=61044.msg810498#msg810498 and they don't look like previously shown pics by neutrino http://taperssection.com/index.php?topic=50750.msg660192#msg660192 as I stated in this post http://taperssection.com/index.php?topic=61044.msg812063#msg812063

Then from the uber long Microtrack 24/96 firmware 1.3.3 postings Vismars brought up the issue of s/n ratio varying from left to right (L -78db R -97db) channel http://taperssection.com/index.php?topic=60666.msg812872#msg812872 as Guy Sonic noted previously in his review http://www.sonicstudios.com/mt2496rv.htm
This seemed to be contradicted by jtessier (L and R both -99db) http://taperssection.com/index.php?topic=60666.msg815430#msg815430

Hence i deciced to check my own, I don't have audition or wavelab which the others used so instead used SF 7 and came up with a disappointing -78db left and right (but hey at least I guess it's the same).
I then decided to open up my MT to poke around inside and discovered at least some of the components have different ident numbers from those pictured by tooldnv.
Compare tooldvn's internals
http://www.dvnaudio.net/ts/10.jpg


With mine
http://i65.photobucket.com/albums/h208/Cybermansrevenge/CIMG0469.jpg


Its evident that in mine the capacitors near the TRS sockets are labelled 5g 4.7 50V while tooldvn's are ?458K 6.8 50V I wonder if this change has been done to improve the s/n ratio.

Now I don't know what tooldvn's results for noise are I'll pm him now and my bet is it'll be near those of neutrino. I also don't know when my MT was manufactured as I bought it from the yardsale in Feb but the serial number is 2452079000775 for what it's worth.

Sorry if this posting is complicated and difficult to make sense of, in that way it's similar to all the other MT postings and indeed the MT!

[udovdh]

So maybe I'd need to measure the SNR performance and start a return if the performance is worse than 90 dB?     
I mean: quite a difference, without any mention by M-Audio.

[cybermansrev]

Post up those noise figures.

[udovdh]

When just recording silence from 1/4", no mics attached, I get -80/-84 dB (L/R) from the SF stats. 
Is this an acceptable way of measuring?

[scoper]

When just recording silence from 1/4", no mics attached, I get -80/-84 dB (L/R) from the SF stats. 
Is this an acceptable way of measuring?

This brings up a valid point - how can we (the taper) measure the noise floor for our gear?

Run it with nothing attached, and check the various RMS values shown a la Audition or CEP? Or do we need to generate some kind of signal into the input? To measure the mic preamps, it seems we would need something attached to either the 1/8" or the TRS input.

Techie advise needed

[Busman Audio]

I am going to work on a mod for the microtrack in the next 2 weeks since I just finished the R4. I will keep you guys posted on what is to come. I know that just a few small mods will make this thing sound a hell of a lot better. The aim is to make it a viable tool for stealthing without a separate pre A/D.
My mods will be available through Cascade media and we will offer them to those that already one the microtrack as well as new units.

[udovdh]

Sounds interesting!

[it-goes-to-eleven]

Good info...   I can't help but wonder if simply extending the shielding to completely wrap the 1/8" and 1/4" sockets would help.

[Nick's Picks]

question...
what is everyone doing to get a S/PDIF cable to fit into these things?

[Busman Audio]

You can only use certain types like the Hosa cable that Cascade media sells. Or you can shave off some plastic around the connection

[JasonSobel]

there are many RCA jacks which fit the S/PDIF input connection.  the Hosa is one of them.  I use a right-angle switchcraft RCA on a DIY coax cable.  works like a charm.

[cybermansrev]

Good info...   I can't help but wonder if simply extending the shielding to completely wrap the 1/8" and 1/4" sockets would help.

That was my intention when opening the MT but now believing there's different internals I think it'll be a bigger job.

[cybermansrev]

Just like Buses (no pun intended) you wait for one then along come two together,
after

I am going to work on a mod for the microtrack in the next 2 weeks since I just finished the R4. I will keep you guys posted on what is to come. I know that just a few small mods will make this thing sound a hell of a lot better. The aim is to make it a viable tool for stealthing without a separate pre A/D.
My mods will be available through Cascade media and we will offer them to those that already one the microtrack as well as new units.

In reply to my question on the Oade Forum if Doug would explain his own mods to his MT he replied
I so wish I had the time to do that ! Working with the smallest SMD devices made to date is not easy and requires a high level of skill to accomplish without torching the PCB. Even if I had the time to work out a clear post on the procedure, I would be eaten alive by request for help to undo the damage...
Anyone who bought it from us and is willing to let me void their warranty with no expectations of support for anything other than the parts I put in, send me an email via this board...
Doug


So a solution to some MT problems seems to be on horizon for you lucky Yanks who've purchased MT's from certain outlets.

[udovdh]

When just recording silence from 1/4", no mics attached, I get -80/-84 dB (L/R) from the SF stats. 
Is this an acceptable way of measuring?

This brings up a valid point - how can we (the taper) measure the noise floor for our gear?

Run it with nothing attached, and check the various RMS values shown a la Audition or CEP? Or do we need to generate some kind of signal into the input? To measure the mic preamps, it seems we would need something attached to either the 1/8" or the TRS input.

Techie advise needed

No advice yet?
In the mean time I did a frequencey analysis in AA over a few seconds of the same silence (1/4" input, 48 Khz, minimum gain, nothing attached) and got a noisefloor below -96 dB.
We need info if this is a correct method of determining the analog performance of the MT so we can compare after mods have been performed.

[scoper]

I spoke with Leonard at Sonic Studios about the analog testing yesterday... I'm not a techie, and thus didn't understand everything (ok, most things) he said, but he made it clear that some kind of input should be attached, even if there is no active signal - I'll try it by attenuating the mic signal down to zero into both the 1/8" and TRS inputs. and measuring the noise at that point with various gain from the preamp at various input settings.

Based on my experience with amplified music, that seems to be no problem at all. Very quiet stuff will be another story.

[it-goes-to-eleven]

I don't know too much about this but I do know that measuring gear with a false load or no load is problematic because you can end up measuring the error of the load resistor or the caps that block the phantom power, etc.  What tolerance was the resistor you used?

[guysonic]

I don't know too much about this but I do know that measuring gear with a false load or no load is problematic because you can end up measuring the error of the load resistor or the caps that block the phantom power, etc.  What tolerance was the resistor you used?

Suggest using 1000 ohm 1% metal film to ground (each of TRS bal inputs; need 4 resistors for this)

below is what I got with the TRS inputs using CEP to look at the recordinga made of the input noise.

[cybermansrev]

Suggest using 1000 ohm 1% metal film to ground (each of TRS bal inputs; need 4 resistors for this)

Could I just get your confirmation that what your saying is to connect a 1k resistor between tip and sleeve and a further 1K between ring and sleeve to simulate a load (on each TRS jack)?

[guysonic]

Suggest using 1000 ohm 1% metal film to ground (each of TRS bal inputs; need 4 resistors for this)

Could I just get your confirmation that what your saying is to connect a 1k resistor between tip and sleeve and a further 1K between ring and sleeve to simulate a load (on each TRS jack)?

In other words, connect 1K ohm (4 total) resistors each from tip-to-ground, and ring-to-ground for each channel.

[udovdh]

Closest I can get here is about 1K2 Ohms.
Also I use the MT only in unbalanced mode.
So I can ground the ring?

[guysonic]

Closest I can get here is about 1K2 Ohms.
Also I use the MT only in unbalanced mode.
So I can ground the ring?

Yes, you can do the noise tests with ring grounded, and tip with the 1000 ohm resistor to ground connection

[neutrino]

Has anyone considered modifying the 1/8" input jack to act as a carrier to the 1/4" jacks by cutting the traces for the 1/8" inputs and re-routing them to the 1/4"? This would be done with the purpose of avoiding the necessary use of any converter cables for someone who what's to run stealth mics or any input with a 1/8" connector.
dB-

[udovdh]

Has anyone considered modifying the 1/8" input jack to act as a carrier to the 1/4" jacks by cutting the traces for the 1/8" inputs and re-routing them to the 1/4"? This would be done with the purpose of avoiding the necessary use of any converter cables for someone who what's to run stealth mics or any input with a 1/8" connector.

I have this mod on my list of things I'd like to be modded on my MT.
Did not find someone yet who could do this.

This mod, plus the reduction of the ever present gain by 6 dB or so would be enough for me; maybe a battery mod?

[it-goes-to-eleven]

It isn't a matter of 'could' it is a matter of 'would'.  Those are simple mods and easy to do (with the exception of the battery).

How much are you willing to pay for those mods to a $300 product? And let's say the MT case gets cracked while being opened, how does the person doing the work get a replacement part? What if the mt just doesn't work after being opened up (not modded, just opened up..)? I am not offering to do work on microtracks, just pointing out that there isn't much of a biz case for the mods.

[udovdh]

It isn't a matter of 'could' it is a matter of 'would'.  Those are simple mods and easy to do (with the exception of the battery).

How much are you willing to pay for those mods to a $300 product? And let's say the MT case gets cracked while being opened, how does the person doing the work get a replacement part? What if the mt just doesn't work after being opened up (not modded, just opened up..)? I am not offering to do work on microtracks, just pointing out that there isn't much of a biz case for the mods.

The product cosst more over here.
If the MT is $300 I may want to spend $150 for the mods I described (except battery mod) including snailmail shipping.
$200 with the battery?

[cybermansrev]

Has anyone considered modifying the 1/8" input jack to act as a carrier to the 1/4" jacks by cutting the traces for the 1/8" inputs and re-routing them to the 1/4"? This would be done with the purpose of avoiding the necessary use of any converter cables for someone who what's to run stealth mics or any input with a 1/8" connector.
dB-

This mod would be easy to do but pretty much pointless!
Yes you would be able to use a smaller jack to attach your mics/preamp but you would still have the problematic noise from the 1/4" inputs gain stage and crucially no powering to the mics (c.f. a dongle).

[neutrino]

Pointless?
 The MicroTrack does not except a line level through the 1/8" inch input like it does to the 1/4" input. I know several people here like myself who run dpa4060's and have to run them into the 1/4" inputs with all kinds of adapters because the output of the mic is just too hot for the 1/8" input. So the "point" is to utilize the 1/8" jack while utilizing the low gain of the 1/4" inputs. It's either this - or reverse engineer the analog path of the 1/8" inputs and replace whatever microscopic components are adding gain to the signal.
dB-

[cybermansrev]

I myself am running 4061's via a homemade dongle into the 1/4"'s but I can't see the point of the mod your describing, yes you have something closer to line level (but still 6db higher according to some postings), But then you still have to power the mics either with a battery box (SP or DPA) or MMA 6000 so there's no gain in carrying less stuff or being more stealthy.

It's either this - or reverse engineer the analog path of the 1/8" inputs and replace whatever microscopic components are adding gain to the signal.

For me this is the real way forward, although as I posted in the oade forum I don't have the bottle (or eyesight) to do it myself.

[neutrino]

If anyone has any insight on the 1/8" signal path and would like exchange ideas, let me know. Since I prefer to run my R1 over my MicroTrack, I'm willing to chop mine up a bit to see what kind of improvements can be made. I'm fortunate to have access to quality solder re-work stations with lighted scopes so working some of these microscopic components isn't as taxing.
dB-

[udovdh]

This mod would be easy to do but pretty much pointless!
Yes you would be able to use a smaller jack to attach your mics/preamp but you would still have the problematic noise from the 1/4" inputs gain stage and crucially no powering to the mics (c.f. a dongle).

I have a battery box. What noise are you talking about?

[udovdh]

I myself am running 4061's via a homemade dongle into the 1/4"'s but I can't see the point of the mod your describing, yes you have something closer to line level (but still 6db higher according to some postings), But then you still have to power the mics either with a battery box (SP or DPA) or MMA 6000 so there's no gain in carrying less stuff or being more stealthy.

For me about 6dB reduction or maybe 10-12 dB would be best. YMMV. Maybe the L/M/H switches can be changed somewhat so that the gain ratio's are modified?

It's either this - or reverse engineer the analog path of the 1/8" inputs and replace whatever microscopic components are adding gain to the signal.

For me this is the real way forward, although as I posted in the oade forum I don't have the bottle (or eyesight) to do it myself.

Can we improve on the opamps, etc used?
Can they be `easily` replaced? (BGA?)

[Nick's Picks]

what about an inline attenuator ?

[cybermansrev]

what about an inline attenuator ?

Well it would certainly reduce the db but would also worsen the s/n ratio and mean more gear.

[neutrino]

I've been successful with modifying the gain on the 1/8" inputs - it's now dropped by -6db. As soon as the appropriate parts arrive next week I'll finalize the gain down another -6db and audition a couple of opamp replacements. Unless you work in a technical repair facility with access to proper re-work equipment, I unfortunately would not suggest taking a crack at modding the MT. The components which need replacing are really microscopic and their placement on the circuit board is so tight next to other components, that it is so easy to destroy other components in the process, or pull pads and/or traces off the board - which is the worst.
dB-

[udovdh]

I've been successful with modifying the gain on the 1/8" inputs - it's now dropped by -6db. As soon as the appropriate parts arrive next week I'll finalize the gain down another -6db and audition a couple of opamp replacements. Unless you work in a technical repair facility with access to proper re-work equipment, I unfortunately would not suggest taking a crack at modding the MT. The components which need replacing are really microscopic and their placement on the circuit board is so tight next to other components, that it is so easy to destroy other components in the process, or pull pads and/or traces off the board - which is the worst.

Hmmm. Getting the 1/8" input levels on par with the 1/4" ones or slightly lower (less sensitive) would be nice.
Would that be possible? Would the audio performance be the same as the 1/4" inputs?

[neutrino]

I've been successful with modifying the gain on the 1/8" inputs - it's now dropped by -6db. As soon as the appropriate parts arrive next week I'll finalize the gain down another -6db and audition a couple of opamp replacements. Unless you work in a technical repair facility with access to proper re-work equipment, I unfortunately would not suggest taking a crack at modding the MT. The components which need replacing are really microscopic and their placement on the circuit board is so tight next to other components, that it is so easy to destroy other components in the process, or pull pads and/or traces off the board - which is the worst.

Hmmm. Getting the 1/8" input levels on par with the 1/4" ones or slightly lower (less sensitive) would be nice.
Would that be possible? Would the audio performance be the same as the 1/4" inputs?

Yes, the mod that I did would come close to matching the input levels of the 1/4" inputs. Doug Oade has mentioned that the 1/8" jacks prove to be less noisy - so given a proper gain mod to the 1/8" circuit, it would out perform the 1/4" inputs.
dB-

[udovdh]

I am going to work on a mod for the microtrack in the next 2 weeks since I just finished the R4.

Got any updates? I am very interested!

[udovdh]

Interesting, will send a PM.

[udovdh]

Does anybody here have some more info on the audio paths from the 1/4 & 1/8" inputs up until the ADC chip?
What parts are in between? Caps, resistors, opamps, etc?

[headroom]

I would like to listen my recordings from the Microtrack direct digital out.
Somebody know how to install an SPDIF OUT Option for this device. Maybe tapping  it  before the DA Stage in Coaxial wire mode. Needs then a little transformer.
Any Ideas around?

[guysonic]

I would like to listen my recordings from the Microtrack direct digital out.
Somebody know how to install an SPDIF OUT Option for this device. Maybe tapping  it  before the DA Stage in Coaxial wire mode. Needs then a little transformer.
Any Ideas around?

Even if practical to kludge in a digital output, this deck has really lousy controls/response for advancing or reversing the recorded file playback positions.  Seems easier to just use a computer card reader and maybe a low cost external USB soundcard (M-Audio Transit) with digital output to get a SPDIF audio to your choice of audio playback system?

[yousef]

I never noticed this thread before...

Looking at a couple of the older posts which suggest some changes to the MT's components over time, I wonder if this could account for the fact that on guysonic's review, the 1/4" inputs are said to be able to cope with a +3.2dB level while mine (and those of several other people who have posted here) can't even cope with a domestic line level (?-10dB)?

[guysonic]

I never noticed this thread before...

Looking at a couple of the older posts which suggest some changes to the MT's components over time, I wonder if this could account for the fact that on guysonic's review, the 1/4" inputs are said to be able to cope with a +3.2dB level while mine (and those of several other people who have posted here) can't even cope with a domestic line level (?-10dB)?

1/8" ministereo input has NO line level ability.  Only the dual 1/4" input has the higher +3.2 dB line level acceptance without clipping.

Refer to chart of input characteristics at: www.sonicstudios.com/mt2496rv.htm#inputs

[yousef]

1/8" ministereo input has NO line level ability.  Only the dual 1/4" input has the higher +3.2 dB line level acceptance without clipping.

Refer to chart of input characteristics at: www.sonicstudios.com/mt2496rv.htm#inputs

I am referring to the 1/4" inputs only. I and several other people have posted on TS about the 1/4" line inputs being unable to take a domestic line level signal (with v1.4.5 firmware, 27dB boost off, L/M/H set to 'L' and recording levels set to minimum).

Edit:

just done some "tests".

i) cd player line-out directly into MT's 1/4" inputs - red clip lights constantly lit
ii) same cd but via hifi amp line-out into MT's 1/4" inputs - red clip lights constantly lit
iii) same cd via hifi amp line-outs>-18db passive attenuator box set to full attenuation - unclipped signal peaking at the "-12dB" mark on the MT as per http://www.sonicstudios.com/mt2496rv.htm#vu

At all times with v1.4.5 firmware, 27dB boost off, L/M/H set to 'L' and recording levels set to minimum. As a comparison, my D8's line-in will take these signals happily but cannot take a +4dB without attenuation.

[guysonic]

1/8" ministereo input has NO line level ability.  Only the dual 1/4" input has the higher +3.2 dB line level acceptance without clipping.

Refer to chart of input characteristics at: www.sonicstudios.com/mt2496rv.htm#inputs

I am referring to the 1/4" inputs only. I and several other people have posted on TS about the 1/4" line inputs being unable to take a domestic line level signal (with v1.4.5 firmware, 27dB boost off, L/M/H set to 'L' and recording levels set to minimum).

Edit:

just done some "tests".

i) cd player line-out directly into MT's 1/4" inputs - red clip lights constantly lit
ii) same cd but via hifi amp line-out into MT's 1/4" inputs - red clip lights constantly lit
iii) same cd via hifi amp line-outs>-18db passive attenuator box set to full attenuation - unclipped signal peaking at the "-12dB" mark on the MT as per http://www.sonicstudios.com/mt2496rv.htm#vu

At all times with v1.4.5 firmware, 27dB boost off, L/M/H set to 'L' and recording levels set to minimum. As a comparison, my D8's line-in will take these signals happily but cannot take a +4dB without attenuation.

Likely there's something WRONG with your MT deck as you seem to have properly inputted an unbalanced but acceptable (grounding the TRS Ring -minus input?) TR signal that should allow unclipped indication and clean recording. 

And you are saying this same CD player's output (without -18 dB attenuator) is OK without distortion into D8's line input?

If so, it may be time to contact M-audio customer service to get this faulty MT deck repaired and the problem resolved.

[yousef]

And you are saying this same CD player's output (without -18 dB attenuator) is OK without distortion into D8's line input?

Yep - no problems there.

Likely there's something WRONG with your MT deck as you seem to have properly inputted an unbalanced but acceptable (grounding the TRS Ring -minus input?) TR signal

Well, I'm not so certain about that - it seems that other people have experienced this and metioned it here from time to time:

http://taperssection.com/index.php/topic,52968.15.html
http://taperssection.com/index.php/topic,53678.msg704471/topicseen.html#msg704471
http://taperssection.com/index.php/topic,66447.msg891930/topicseen.html#msg891930

I'm not sure if it's mentioned explicitly in these threads but I'm sure that I've repeatedly read about the MT adding 14dB of gain to the TRS inputs and that this can't be turned off.

Which brings me back to my original wonderings - with the differences in components mentioned earlier in this thread, would it be possible that there are effectively two different versions of the MT out there: one that can take line levels and one that can't? Perhaps we could have a straw poll with comparison of serial numbers?

[Lil Kim Jong-Il]

Perhaps we could have a straw poll with comparison of serial numbers?

You can start a poll thread.

[yousef]

You can start a poll thread.

Another new skill acquired:

http://taperssection.com/index.php/topic,81722.0.html