tab-funkenwerk T58 transformer

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antichef

antichef

pornk rock
Since Chance's recent announcement, visions of TAB-Funkenwerk transformers are likely dancing in all our heads. When I ordered the BV314 from Oliver (Archut of TAB-Funkenwerk) to send to Marik to put into the ACM-6802T, I also ordered one of his T58 transformers, and now I have it.

t581-orig.jpg


The T58 is intended as a replacement for the SM57 or SM58, so I suppose it's different from the ones we'll be seeing through TnC, but nevertheless, if anyone's interested, I'm happy to chronicle my adventure in this thread.

I've got a few old SM57's and one really beat up SM58 (and another that I did the "transformerless" mod on, but I plan to leave that one alone). I had planned to put the T58 into the nicest of my SM57s - the one I bought new - but I'm open to suggestions about other ways to use it. Oliver has plated the terminal ends with silver, and so I'm thinking he's thinking that it should be installed once and left alone afterward, and so that's what I'm thinking, too, and I want to make sure I pick the right application.

Also, I'm assuming that before/after comparisons would be nice. Any guidance as to what sort of sounds to use for the comparisons? I post a lot of before/after samples here, and often wonder how helpful they are, so this time I'm trying to plan a little better (but note - I won't be able to do an all out drbill-style shoot-out, alas)
 
Yeah, Oliver is very good. You would be amazed at the E-mails I get asking questions like "which Radio Shack transformer should I use?"
 
It should be relatively simple--the top applications for SM57s are guitar cab and snare, so just put a modded 57 next to an original, and record the same source with both mics at the same time using a two-channel (or more) preamp. The input impedance of the preamp will have an effect on how the mics are loaded, so it's best to stick with a preamp that has typical input impedance of 1 to 1.5K ohms. Now, it might actually be better to use a preamp with a higher input impedance, but that will make the comparison less useful for the masses who don't enjoy that feature.
 
OK, good then -- I'll select two 57s - one for the mod, and another as a "control" - this'll help preserve some accuracy while giving me some more time to work on things. First, I'll record some "before" samples with both mics (happily, even though I'm not a drummer and don't have a drum set, I do have a snare, and I have *lots* of guitar amps :) ), and then I'll do the mod, and then I'll come back record "after" samples with both the (unmodified) control mic and the modded mic.

I've got an ART Digital MPA with variable impedance, so I'll use that. I'll try and use one other preamp, too.
 
antichef said:
(happily, even though I'm not a drummer and don't have a drum set, I do have a snare, and I have *lots* of guitar amps :) )
Click to expand...

Seriously, all you want to do is bang on the snare on quarter notes. Anything more is a distraction from what you are really trying to hear. So a series of soft hits, then a series of lot hits. Some brushwork if you really want to go crazy. With and without wire maybe.

Guitar is a bit trickier as you need to cover the full range, so pick a full-range phrase, but end it with something like an open chord that you let fade naturally, for like 30 seconds.
 
OK - completed the mod -- details of the activity with pictures are in the DIY forum in this thread:

https://homerecording.com/bbs/showthread.php?t=273513

Here are some sound samples. I was totally rushed to get all this done (as I always am), and so couldn't be as scientific as I would have liked. For instance, I did the "before" samples on a different day from the "after" samples, due to time constraints. To help correct for the inherent problems with this, I took pictures of mic placement (which was very doubtfully optimal, again due to time constraints), like this one:

micedamp.jpg


to help make sure I used the same placement for the after samples, and more importantly, I used a "control" SM57 (not real well matched to the modded one prior to the mod, but that's how these things are) -- this mic was present and unchanged in both before and after samples. Those of you with good ears and brains can hopefully notice the changes in the control microphone sound in the before/after samples, and "correct" for those same changes in your evaluation of the modded microphone.

The way this works is that I have two wav files for each type of test, one for the control, and one for the mod; each wav file (except the last set) first plays the pre-mod sample, then cuts to the post-mod sample. The files range in size from almost 10 megs (the snare) to over 17 megs (the guitar), so keep that in mind. edit: I just added MP3s

First, here's the snare -- I went out and got "brushes", but they're the nylon kind and I don't know how to hit with them, so it just sounds kind of lame (the first hits are with regular sticks, though):

http://www.recursor.net/t58/snare-control.wav (
) -- the control mic

http://www.recursor.net/t58/snare-mod.wav (
) -- the mod mic


Next, here's the guitar amp - a modded Blues Jr. using a brand new Weber speaker. I was unable to "reamp" due to a bunch of noise in my setup when I tried it -- EM problem no doubt, but I had no time to solve it, so I just played both times. Big difference in gain between the before and after, and I'm not sure why, since I thought I was sure of the settings. But that's what the control mic is for :D:

http://www.recursor.net/t58/guitar-control.wav (
) -- the control mic

http://www.recursor.net/t58/guitar-mod.wav (
) -- the mod mic


now, for a bonus, here's a mystery instrument -- I only have "after" samples, but I do have both mics. Placement was similar, but, unlike the snare and the amp, I was not able to do a "symmetrical" kind of arrangement, so I'm sure there are placement differences. If the t58 needed a "burn-in" period, I'm sure this took care of it :D

http://www.recursor.net/t58/pipe-control.wav (
) -- the control mic

http://www.recursor.net/t58/pipe-mod.wav (
) -- the mod mic
 
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How long are the .wavs? If you cut them down to 30 seconds, that will help with the DL times . . .
 
The snare samples sound identical to me. I like the guitar amp, though. Less mush more mid. Sounds like a 57 after I've eq'ed it a bit. Still sounds like a 57 though.
 
actually, I just made mp3s on the server, so I'll edit my post
 
One thing that is a bit curious is the guitar samples are 4dB different, whereas the snare is about 1dB different in the other direction. So I don't really know if the transformer changed the output level (it probably did), or if there was a problem with gain settings on the preamp. Those aren't major issues as they can be fixed with matching levels (which should be done before the samples are auditioned), but it raises the issue whether the placements were truly identical. I think the difference on guitar was too large to be accounted for with placement though.

Overall, I think the change was a drastic improvement. It's so large a difference on guitar that I don't even think the fact that the samples weren't blind matters. Snare is closer, but the new trafo still has a better, more natural frequency response. The stock 57 reminded me why I always like Beyers much better. The modded one I would bet is competitive; then it just becomes a cost/hassle issue (an M201 is $170 new I think).

But then I've seen people say the M201 doesn't have that great of a trafo either . . . it never ends, does it?
 
There probably were placement issues. Output of the T58 is a little lower than the stock tranny, I believe, but between the before/after, it could also be that I was hitting the snare harder in the after samples.

The amp definitely sounded different in the after samples -- sorry about that - I could even tell when I was playing, but didn't have time to correct (wife was on the way home from shopping :D)

I agree about the guitar -- I may be using this in addition to/ instead of ribbons at times.

Wish I could do a proper vox test. I might compare the modded mic to a SM7 soon. I've never used any Beyer mic -- hopefully that'll change someday -- it does never end :)

Any comments on the bagpipes?
 
Hey Antichef,

Thank you for these samples--I was very curious to hear the difference, which indeed, is not small.
Definitely in all samples the modified sounds more clear and transparent. I'd attribute it primarily to the DU type of core used (same as Cinemag 2480 and some AKG mics).

This is a matter of taste and some folks would probably disagree with me, but to me the T58, as well as 2480 clarity and flatness is bordering with some kind of sterile and boring sound (for lack of better term).
To me the original is much more emotionally engaging and natural sounding. Sure, it is more distorted and more colored, but on the other hand, maybe this is one of the reasons this mic became so popular. Color and distortions is not a necessarily bad thing (esp. on an amp). If I wanted clean dynamic I'd probably just reach for a different mic.

But this is only my opinion.

Best, M
 
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