R-44 Oade Mod vs. Busman Mod (opinions sought)

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I think a fairer test is using just a single pair of mics, and repeatedly switching which of two decks they are connected to over the course of a show, making multiple switches mid-song.  Of course, this means you get a recording that is all chopped up...best to do this when another taper is documenting the whole show, or it's something you don't really care about.  (Or a soundcheck.)

Of course, you won't be comparing the exact same passage, but you eliminate all the other parts of the recording chain that might be different.  With enough blocks to compare, you can see if you consistently prefer just the stock clips, just the modded clips, or if it turns out that the clips you prefer are not consistently from one recorder or the other.  Switching the mics between recorders many times is key, that way you don't need to worry about something like the sound being better in the second set.

If you really want to be a stickler about it, play with the gain controls ever so slightly each time as well, trying to get the levels as consistent as possible but that way you won't consistently have one deck at a different gain setting than the other (aside from differences forced if the mod changes sensitivity dramatically, but that's not something you'd want to discount anyway).  You should probably normalize each clip unless you think the difference between decks is so subtle that any post-processing of the signal will obscure it.

Even better, have someone else do this and provide you with the files, such that only he knows which clips came from which deck.

If your going to go to the trouble of switching every so often, why not just run splitter/"Y" cables?

[Will_S]

I think a fairer test is using just a single pair of mics, and repeatedly switching which of two decks they are connected to over the course of a show, making multiple switches mid-song.  Of course, this means you get a recording that is all chopped up...best to do this when another taper is documenting the whole show, or it's something you don't really care about.  (Or a soundcheck.)

Of course, you won't be comparing the exact same passage, but you eliminate all the other parts of the recording chain that might be different.  With enough blocks to compare, you can see if you consistently prefer just the stock clips, just the modded clips, or if it turns out that the clips you prefer are not consistently from one recorder or the other.  Switching the mics between recorders many times is key, that way you don't need to worry about something like the sound being better in the second set.

If you really want to be a stickler about it, play with the gain controls ever so slightly each time as well, trying to get the levels as consistent as possible but that way you won't consistently have one deck at a different gain setting than the other (aside from differences forced if the mod changes sensitivity dramatically, but that's not something you'd want to discount anyway).  You should probably normalize each clip unless you think the difference between decks is so subtle that any post-processing of the signal will obscure it.

Even better, have someone else do this and provide you with the files, such that only he knows which clips came from which deck.

If your going to go to the trouble of switching every so often, why not just run splitter/"Y" cables?

If you have suitable cables and are sure they are sonically transparent, sure, go for it.  How does phantom powering work through such a cable?  Any weird changes in input impedance?

[goodcooker]

to the OP - this thread wandered off into "comp" land so....

I have never had any Oade modded gear with the exception of a digi mod UA5 so it was really no different "sounding" than it was stock...but I have had two different Busman modded recorders - a Marantz PMD670 and an Edirol R4. The Marantz had totally useless preamps for concert recording before the mod. The R4 I ran stock a few times and I thought it sounded thin and hissy at higher gain. After the Busman mod (vintage1,2, transparent 3,4) the preamps sounded full and rich with negligible hiss even at almost max gain.

The most notable improvement on the R4 was lowering the gain on the inputs (I guess lowering the sensitivity) so that you could use it for concert recording. At rock shows I had to run it at line in (engages 20dB pad) and crank the gain to about 75%. With the lower noise floor also accomplished by the mod I was able to do this without problems.

I guess my point is that the mods accomplish other ends than just changing the sound (or flavor) of the preamps.

The R44 purportedly has better sounding preamps than the R4 so if I were you I would buy a stock unit, run it a few times in a few different situations then decide if you want or need the mod done then.

I run a stock PMD620 now...Oade mods them but I don't see the need....sounds fine to me behind my preamp.

Back to your regularly scheduled "that comp would be useless" banter 

[Myco]

Yeah, I don't have access to a stock R-44 but I'm curious if running my bmp2+ UA-5 is worth carrying in my bag now that I got the Oade CM R-44. So that's why I'm planning a comp between the two. I am definitely interested in hearing a stock R-44, busman mod and oade mod comp though!

I have a busman mod myself. I've heard a few of my teammates talking about getting an oade mod, so if it goes down i'll be sure to run a comp one of these days because a fair amount of these guys run the same mics also.

I've got the splitter cables if you want to use them.

edit: And I suspect Nick might have some as well, just thought of that. If anyone else wants to do a comp off of a single set of mics, I can loan you the cables.

This would probably be the best suggestion, and the most accurate representation of the signal.

A splitter going into the two different decks while using the same mics would provide the same input to both decks, but the splitter would need to terminate in XLR's to input into the analog stage, the coax input would only test the A/D stage which isn't modded as justink pointed out.
Great points page & justink!

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This would probably be the best suggestion, and the most accurate representation of the signal.

A splitter going into the two different decks while using the same mics would provide the same input to both decks, but the splitter would need to terminate in XLR's to input into the analog stage, the coax input would only test the A/D stage which isn't modded as justink pointed out.
Great points page & justink!

Yeah, I've got XLR terminated splitter cables for this specific purpose. I was going to comp the FR2-LE this way and then I sold mine...

I think a fairer test is using just a single pair of mics, and repeatedly switching which of two decks they are connected to over the course of a show, making multiple switches mid-song.

If your going to go to the trouble of switching every so often, why not just run splitter/"Y" cables?

If you have suitable cables and are sure they are sonically transparent, sure, go for it.  How does phantom powering work through such a cable?  Any weird changes in input impedance?

They're standard cabling that we use, but more importantly, both ends are from the same cable stock, so they "sound" the same and won't be a conflicting element. Running two decks against a single mic body will load the body more, however nothing drastic has been reported, there are probably some eletrical engineers or people with more intimate knowledge of loading that could shed some light on it. I got the idea when Dirk did it when he did file sets for people to listen to with pre-amps and this would be done in a similar approach (until then I didn't know it was possible). For running P48, just turn it on from 1 deck, not both.

As for ABX testing, it's the closest we will get to being able to analyze audible differences in a somewhat critical fashion because the only different variable between two file sets will be the gain between the two (however small) and the mods. It's still just one situation (so nature recording, a club, outdoor PAs, crowd noise, etc could be other tests), but it's a relative sample of what we do.

At that point, the two questions to ask are:

• Can you tell a difference?
• If so (and it's not a guarantee), which do you prefer?

The later would most likely require additional tests to determine an overall average, but the former should be reasonably answerable off of one test for the majority of uses that people have here.

Back to your regularly scheduled "that comp would be useless" banter 

It's a slow week so far, we don't have much else to talk about. 

[Will_S]

Running two decks against a single mic body will load the body more, however nothing drastic has been reported,

But even if it's nothing *drastic*, what impacts will it have on potentially subtle differences?

For running P48, just turn it on from 1 deck, not both.

Hmm, it seems reasonable to think that having phantom on versus off could have a subtle effect on a deck's sound. 

That's why I favor the multiple clip approach.  You'll never be able to create exactly equal conditions for both decks, so go with randomization and replication to let the confounding factors average out.  Of course take every step possible to reduce the confounding factors first, but I'm not convinced splitter cables and running phantom on only one deck is the way to go.

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Running two decks against a single mic body will load the body more, however nothing drastic has been reported,

But even if it's nothing *drastic*, what impacts will it have on potentially subtle differences?

I'm not an electrical engineer (aka; shit if I know what load differences do, but it should effect the sound on both boxes the same).  My comment was based on the observation that nobody said anything about it when Dirk or Todd did their comps which were done in similar fashions. It doesn't mean there arn't differences from the stock sound, just nobody said anything (hence nothing "drastic") when comparing two files from the same loaded signal.

Someone else can step up and field this one on the science of what loading does.

For running P48, just turn it on from 1 deck, not both.

Hmm, it seems reasonable to think that having phantom on versus off could have a subtle effect on a deck's sound. 

That's why I favor the multiple clip approach.  You'll never be able to create exactly equal conditions for both decks, so go with randomization and replication to let the confounding factors average out.  Of course take every step possible to reduce the confounding factors first, but I'm not convinced splitter cables and running phantom on only one deck is the way to go.

To me, thats like saying "80% isn't 100%, so I'm going to go with 40% instead because I can't achieve 100%." Comparing clips that are not the same content doesn't lead to sturdy critical analysis. The whole point of doing double blind testing is to mitigate as many factors as possible so any differences that are noted are more likely to be real and not a result of bad research. Having the same source content to compare against is one that is especially pertinant as cymbols may be hit less, instrument volume changed, the room could fill up and create differences between clips, but running the same signal out to two decks mitigates all of these. You are correct in that it doesn't resolve if any modifications were made to the Phantom production or distribution chain, however I think this is smaller issue then not having comparable content which can obscure the results of the basic question of "is there a difference" thus preventing the follow up question about discriptors of differences (presuming there are any).

At the end of the day, I think being able to actually attempt to ABX them against each other and articulate if there are any differences trumps (what I see as) minor issues related to P48 usage and affecting the sound via loading of the microphone (which both decks should experience). Hell, if you want to resolve the P48 question, run a PS2 or 2Phant or whatever else provides P48 without gain between the mics and the decks so neither deck has P48 turned on and both decks will have any sonic imprint that the phantom box is puting into the signal (thus mitigating it as a difference). That just leaves the load issue which I still think is near the bottom of the priority list of effect.

It's a slow news week. 

[datbrad]

Hoping to bring this discussion back to the basic question, I think the difference between Oade and Busman is a matter of personal taste, such as some prefer Honda to Toyota, but essentially there is very little difference in the key performance areas of automobiles between these brands, just styling and "flavor".

I talked to Doug about the overall objectives of modification several years ago when I was looking at his modded gear.

Doug explained that basically none of the prosumer gear made by Marantz, Tascam, Rolland, Fostex, etc. uses premium chips in their preamps that meet specifications we expect for concert recording, or for nature recording at the other end of the scale. With this type of short-cut, mfgs can save enough to impact the price points of their recorders and 90% of the users that buy the decks will not require anything more. Oade and Busman make mods to these units that fit specifc recording conditions that the stock chips are ok for, but not ideal for.

Doug can optimize a recorder's preamps for either the high input sound pressure headroom needed for concerts, or he can select opamps and input capacitors best for soft sources requiring heavy gain and low noise.

You can listen to comps, but the best way to validate Oade's mods is to find someone who had a PMD660 before and after Doug modded it for concert taping, and see what they tell you.

[illconditioned]

Within the realm of opamp swaps there are a limited number of choices you can make.  If you aren't changing any other circuit components, you cannot change the gain range--that is set by external components.  Generally, you are looking at a few specifications, such as noise, gain bandwidth, slew rate, quiescent current, distortion, and rail-to-rail operation.  You cannot change the headroom of a circuit merely by swapping opamps unless you are going from a chip that cannot operate rail-to-rail to a chip that can.  That feature is often exclusive of speed, since the market for faster chips usually also has a high enough power supply that rail-to-rail is not important.  Thus, rail-to-rail is a more common feature in chips designed for low voltage supplies.

When you go to faster and quieter chips, you may find that power consumption (quiescent current) will increase if the stock chips selected were low-power types.  That could be benign, but it will mean reduced runtime.

From what I can tell, the biggest problem is the rail voltages.  Edirol seems to use +/-5V (UA5, R4).  Fostex FR2-LE is 8V (single sided).  I've seem some Maudio gear (MobilePre) with only 5V (single sided).

Low voltage and faster opamps seem to help.  I've used AD8620 (expensive) and more recently LM4562.  The LM4562 are very nice, the latest National Semi audio product, and operate at less than 5mA per channel.  They have low noise and are spec'd down to +/-5V.  They are approx $5 at Digikey.com.

  Richard

[Will_S]

You can listen to comps, but the best way to validate Oade's mods is to find someone who had a PMD660 before and after Doug modded it for concert taping, and see what they tell you.

But the PMD 660 was a particularly bad piece of gear - noisy and easy to overload.  The R44 and FR2LE spec out (and by all accounts, sound) a lot better stock than a stock 660 does. 

[datbrad]

You can listen to comps, but the best way to validate Oade's mods is to find someone who had a PMD660 before and after Doug modded it for concert taping, and see what they tell you.

But the PMD 660 was a particularly bad piece of gear - noisy and easy to overload.  The R44 and FR2LE spec out (and by all accounts, sound) a lot better stock than a stock 660 does.

Good point.

In in keeping with fair disclosure, my reason for getting the Oade warm mod 661 was not really seeking an improvement in specs, but rather to obtain a recorder sound as close to the professional analog and early pro DAT recorders I grew accustomed to their FET input sound during the '80s and early '90s. Listening to both Oade and Busman warm mods, I already was leaning that way when Doug Oade introduced the warm mod 661.

[colors]

I've done an A/B of my stock R-44 and Oade Super Mod R-44.  Ran X/Y KSM141 pairs into each.  2 files, one the modded, one the stock.  have at it!

http://www.alanmunshower.com/dump/a.wav

http://www.alanmunshower.com/dump/b.wav

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so no one wants to take a stab at it huh?  maybe I should start a new thread...

[printguy]

I've got them downloaded, just need to get some time to sit and listen. Through my laptop speakers at the office won't tell me anything!

[Gutbucket]

OK, I clearly prefer b.

Any chance you have additional files with the mic sets swapped?