TG-1 transformer comparison

Hi Group,
I haven't yet settle on which transformers to build into my Fester's TG-1, in fact I am happily running it in 'clean' mode most of the time. However, when I have a transformer knocking about for another project, I quickly test it to see if it is a possible candidate. I recently bought a few Lundahl 5402s for a G-Pultec and gave them a try in the TG limiter, primaries wired in parallel for 1:1 gain.  I have made up a little mono test file consisting of bass/guitar/vocals/drums and ran this through the TG in bypass/clean/iron modes without much level matching. you can hear the result here:
https://www.yousendit.com/download/K0JSZ28zTmFPSHl4dnc9PQ
Now for the fun part, please let me know which of the files (A/B/C) is bypass/clean/lundahl respectively, and also which one you like best
The yousendit link will expire in 7 days, but if anyone would like to host this permanently I am happy for them to grab the files and I will change the links accordingly. I would also love for other people to post soundexamples of their transformers, you are very welcome to use my bypassed file to do this.
and now - Happy guessing  ;D

I can't play the files; mind telling what format, etc they're in?

This almost rings 'Studio A'...


Edit: Aiff 24 bit? Ok. Quicktime works.

A: Lundahl
B: Clean
C: Bypass

Favorite: B (other than bypass/drums)

Well, did i get it right or what? 

Okay, I'm too much of a self-professed amateur to make wild guesses and I'm not sure this is what you asked for. Anyway, I briefly listened to the files a few days ago and felt that File A sounded somewhat dull. And what happened to the snare? File B, hm, I did not really like it either, but snare was better. And file C sounded uncontrolled.

Donno, but if File B is indeed without transformers, then why not leave it at that? To be honest, I never really understood why people feel the urge to add transformers to a piece of gear, although it would work perfectly fine without. Instead, why not build a TX box with several Ins and Outs, switchable attenuators and Zobels, clean in/out stages, input drive and what not, thus having the possibility to patch in any transformer before or after any kind of gear whenever you feel you need a little 'couleur'. Again, if File B is indeed 'clean' (and that's what I'd want from a limiter), I'd put the lid back on and rack it (for good (use)).

So, now I'm curious what the files are

Script said:

File B, hm, I did not really like it either, but snare was better. And file C sounded uncontrolled.

Click to expand...

Then you don't like compression, which is a good thing.  File C is uncompressed; hence, uncontrolled.
I don't mind file B. It's up to you, how you use it.

ok i guess game is over, desol, you did indeed get it right in one ;D

I am just gonna come straight out and say that I couldn't really hear a difference between A (lundahl) and B (clean compression) when blind tested.
I didn't level match C (bypass), so that's why it's loud and uncontrolled.
I also came to the conclusion that there is no point in a 1:1 transformer set up, so now I am going to aim for the Ch@ndler variation with the 'wrong' transformers and the 'broken' gain staging. If that's unconvincing too, then it's back to transformerless, which I like as a sound on its own.

thanks for playing  8)

Man, it was easy! Glad it was correct...


B (compressed) was simply more open in the deep low and high top end.

A (compressed) was constricted. (lundahl)

C was natural sounding and the drums sounded the best.

As far is listening practice, i can thank Terry at PSW for his wisdom.


The Chandler version is more aggressive, if that's what you're after.

desol said:

Script said:

File B, hm, I did not really like it either, but snare was better. And file C sounded uncontrolled.

Click to expand...

Then you don't like compression, which is a good thing.

Click to expand...

Hihi, I think you might be right on that one

Indeed I tend to rather not like compression, and that's probably why I get more and more of them units. Actually I like things to be controlled but sound transparent and retain some amount of dynamics. And limiting I like when it allows me to tame transients in order to raise the RMS level, but it still sounds transparent, unless it's an explicit effect that I'm looking for.

And yes, I cherish the full frequency spectrum 8). The Lundahls on that unit (that demo track) were a bit disappointing, I think. Maybe it needs a different A/R setting? Maybe it's just the wrong TX for the unit? I don't know, I don't have that unit and I don't think it would do something for me that I cannot achieve otherwise, but I remember having read somewhere that leaving out the input TX should make it closer to the EMI TG12413, and that the input TX and gain function change turn it into a 'THD box'. Well, someone said and what do I know...

@ Briomusic
Thanks a lot for the hassle of recording the tracks. It was interesting. Too bad not more people chimed in. I really would have liked to hear more opinions too, but maybe it was to be expected...  :-X
Curious to hear about the next TX tests...

@Script - the compression on this file is quite strong cause I wanted it to be obvious. Also, I used the same setting on a whole bunch of signals in that test file. for example the bass and vocals are quite loud in the original/bypass file so is compressed more than the guitar for example. In the real world I would probably parallel-compress the drums.

The 1:1 Tx are not really a clone of any existing machine, EMI style would be transformerless and Ch@ndler style would have Neve/Carnhill transformers and mad gain staging. ("THD machine") I will try this next 

C, uncompressed file : easy.
But for A and B, I wouldn't have been able to found wich one is the transformless and the Lundahl.
Anyway, except for the drums where I prefer the transformless B sample, I prefer the A.

Otherwise, how difficult is this built ? Difficult finding components ? Need serious skills ? I'm a newbie and so far, I've build with success 1 S800 EQ, 1 EZ1290 preamp and 2 1176 rev A. Am i ready to build this one ?

Thanks for having post these files, I love sound samples. I'll soon post 1176 samples : 3708/5088 transistors comparaison and also a caps one.

Ben A.

As far as I'm concerned the original units (desks) had a input TX 1.732:1 and an out TX 1:1.732.

Input Transformers
The left and right signals from the transpose button pass to input
transformers which step down in the ratio of 1.732 : 1 thereby reducing a standard
line level input signal of l.228 V (+ 4dBm in 600
) to 0.709 V (+ 4dBm in 200
),
this being the standard internal interconnection level.

briomusic, what about SNR? I tested a Lundahl TX for the output and although the sound difference is almost unnoticeable, I managed to get a few dbs better SNR, which is a good thing I suppose, so it might worth using TXs. Also, you can get a bit more headroom by using 1.732:1 (or 2:1) and 1:1.732 (or 1:2).

ok kids, time for round two 

this time I had a bunch of carnhills from colin at audiomaintenance.com to play with.
output is always the VTB 1148, mostly wired 1:1.7 (except one file where I tried 1:3.4)
more variety on the input transformers:
VTB 9046 (line input, borrowed from the EQN kit) wired backwards in 1:2 and 1:4 configuration
VTB 9045 (mic input) wired in 1:2 and 1:4 configuration

http://www.yousendit.com/download/UFVyc0wzTmFwaFEwTVE9PQ


I tried to adjust the input level for each config so that the snare would get 8dB gain reduction (or whatever that meter means  ) output levels are roughly matched, but not anal-retentively so. 

The objective for me was to get as far away as possible from the original non-iron sound and into ch@ndler/THD territory - otherwise why bother? I did find a configuration I liked which is now accessible with the iron switch, while still having the clean option as well.
that uncle fester is a crafty fellow!  ;D

have fun playing.

mmmm, interesting post....

hey briomusic,

could u be so kind as to let us know how u connected the gain stage for this unit?

much appreciated

mick

I'd be interested in knowing which sound sample corresponds to which transformers.

Also, did you adjust the zobels for each transformer?

Mark

A VTB 9045 1:2
B VTB 9045 1:4
C VTB 9046 1:4
D VTB 9049 1:2
E no transformer
F like A with output 1:3.4

to be honest I completely forgot about the zobels  :-[
isn't this done to dampen down ringing in the inaudible supersonic regions?
I guess I could just steal the zobel values from similar neve circuits or is there a formula?
*scampers off to wikipedia*

btw, me and my assistant liked A best and this is configuration I ended up building into the box.

@leadbreath, I guess by gainstage you mean the non-transformer version?
I am using 604 opamps on the input and nothing on the output.
I changed RIN1 and RIN2 to 10k, leaving RIN3 and RIN4 at 20k. This gives me 6dB gain which matches the 1:2 input transformer, so I have the same amount of gain reduction when I switch from clean to iron.
because I have no output stage in the clean version, the 1:1.7 transformer makes the iron setting a little louder (4dB if I am not mistaken). I don't mind compensating that manually with the output level trim.

isn't this done to dampen down ringing in the inaudible supersonic regions?
I guess I could just steal the zobel values from similar neve circuits or is there a formula?

Click to expand...

It's more to even out the response in the 20-20kHz region.

For example on the 1073 your input transformer (10468/VTB9045) requires a 180pf cap across the secondary to even out the response.

Mark

hi briomusic

sorry i should have been a little clearer, i actually meant the gain staging you mentioned for the Ch@ndler style set up?
as qouted: "Ch@ndler style would have Neve/Carnhill transformers and mad gain staging. ("THD machine")"
is there a pot/switch in the circuit so u can dail in different levels or is it just that the transformer ratios are all wrong?
ive just recieved my pcb's and would very much like the clean option and the THD option.

thanks once again

@leadbreath: have a look at this post: http://www.groupdiy.com/index.php?topic=6481.msg395357#msg395357
whatever one might think of the way transformers are used in the ch@ndler unit - it has become a modern classic in its own right. there are several opinions/guesses on this forum as to what the transformers in the ch@ndler unit are (I believe the input transformer is a custom model and not part of the normal carnhill range). My approach was to try the ones I had access to and use my favourite combo.

hey thanks so much for that link, this helps a lot. did u use a pot on the secondary of the input transformer to adjust the threshold as quoted? if so what size pot did u use?

sorry if im being a pain, i owe u some beers man.

mick