Transformer recommendation for G9

[Eicen]

Hello.

I need some iron for my G9 project. The primary use would be for bass(DI), vocal and guitars(DI)... And maybe some acoustic guitar/bass tracking
I already got a slightly used LL1528 in "stock". So the obvious choice, would be to find another LL1528, and use them as input transformers.

I was told that the output-impedance of the last tube is about 2k4, so should i try to match that? I was also told that a transformer with 4:1 ratio would be better for the output...?
I found some Sowter transformers, i think might be suitable:
Sowter Type 9945 - 10K/150+150 ohms  High Level Line  http://www.sowter.co.uk/specs/9945.htm
Sowter Type 4383 - 600/10K Line Input Transformer  http://www.sowter.co.uk/specs/4383.htm

I also found a EDCOR transformer that might be suitable, but I haven't heard anything (good or bad) about them.. They seem very cheap..?
EDCOR XSM2.4K/600 http://www.edcorusa.com/products/transformers/xsm/xsm2_4k-600.html

I could also save the LL1528 for another project, and go for some other input-transformers?

Or maybe i should stick to Jakob's schematic and use Lundahl or OEP's all the way around..?


Which transformers are you using? and how do they sound?
Do you know any transformers worth recommending? Price range should be around 30-60$ a piece

 

[shabtek]

use the lundahl on 1 mic only channel and make the other dedicated di.
use edcor  2k4:600 on outs.

 

[Eicen]

Thanks for your reply.

Good suggestion, but I would prefer to have 2 similar preamps, so that I'll be able to record stereo tracks.

How does those EDCOR sound?

 

[shabtek]

i've -finished- 2 g9s, 1 a self-etch, one from gustav. I had issues on both with oscillation/ right channel a little funky/noisy...made the di direct wired and that helped. i don't think there were issue with  DI only, but the extra routing from mic xfmr to 1/4" jack and back can pick up some noise. never used them in stereo. always 1 ch DI.
one has oep i/o the other oep in/ big opamp labs xfmrs wired 2:1 on out.
bigger core has better low end
edcor has worked well on gpultec out, so should be good here--but won't fit on pcb
i've got a couple channels (shelved) built p to p 1 DI, 1 mic only, going to try different edcors on outs

 

[rodabod]

The 4:1 transformer will lose you an extra 6dB gain compared to a 2:1. But, the 4:1 will have lower output impedance. It's less of an issue with 10K, 20K, etc. line input stages though.

Transformers are a taste thing of course. Certainly an OEP on the output will have distortion at higher levels, but some people like that. I'd be a little worried about it's response though. I'd stick with something you reckon you know is likely to work well given the 2K4 source impedance at line levels.

 

[Eicen]

The 4:1 transformer will lose you an extra 6dB gain compared to a 2:1. But, the 4:1 will have lower output impedance. It's less of an issue with 10K, 20K, etc. line input stages though.

Transformers are a taste thing of course. Certainly an OEP on the output will have distortion at higher levels, but some people like that. I'd be a little worried about it's response though. I'd stick with something you reckon you know is likely to work well given the 2K4 source impedance at line levels.

I figured the sowter 9945 would be good in this application, hence it has a large core, and the 10k would match the 2k4 quite good? And the output-Z would be quite low.

Do you think the 6dB gain-loss, when using a 4:1 transformer, would become an issue? I haven't used a G9 before, so i don't know how much output it has with a standard 2:1 

 

[zebra50]

I've built 4 (!) G9's in various arrangements now (traded the first, scrapped and rebuilt the second...).

The current one has Lundahls at the input, the OEPs at the output. This is my favourite so far, and I prefer it to the all-lundahl one. It has just enough character. (I do get oscillation with some mics, on the right channel only with both knobs turned all the way up, but I figure that's like driving your car past the red line - it's never necessary).

I did build one with some old BBC iron, which sounded good but it lasted a week before a client in the studio begged me to trade for a guitar!

 

[bernbrue]

Hi,
Beyer input, edcor output. Further details here:
http://www.groupdiy.com/index.php?topic=29830.0
regards
Bernd

 

[Eicen]

Thanks for your answers..
Since i'm going to order another transformer (for another project) at Sowter, i would prefer to order my G9 output transformers there to..

So i guess my question now, is whether the Sowter 9945 is good for G9 output?
Or maybe Sowter has another transformer, that's better in this application?

 

[pstcho]

nobody tryed to replace the transformers (input and output) by amother system (op amp, ...)

and about the 1176?

thank you

 

[Luny Tune]

Keep the 1176 questions to th 1176 thread.

And I have the same answer (question rather) here regarding the G9. Why would you?

 

[josh]

Transformers are a taste thing of course. Certainly an OEP on the output will have distortion at higher levels, but some people like that. I'd be a little worried about it's response though.

Why do you say certainly?  Is this a known characteristic of OEP stuff?  If it is then I definitely want to start looking into this.  Are we talking the good kind of distortion or the bad kind?  Because right now I use my G9 with dual Lundy's strictly for bussing softsynths through, and all this talk of distortion has my underwear in a knot and makes me want to pull her out and put some OEP on the output.

 

[Luny Tune]

I use a GSSL with OEP's in the output for that exact purpose. Well, I love the sound on it on anything I love to use the GSSL on to be precise, but I think there's nothing like it that can "ignite" a sampled e-piano or the EVP88 in Logic. The GSSL is a fantastic comp for pianos and synths (in my opinion) and the OEPs adds that "magnetic yummie" that we trafoholics love.

I also used to have OEPs in the output of my stereo bus passive eq/GSSL and Lundahls in the input. But they're too coloring for my taste there. So I replaced them with Lundahls and now it's just perfect. I use that box for all mastering I do and it adds all the "analogue" that the clients want.

(The OEPs I'm talking about are A262A2E and the Lundahls ae LL5402.)

I've experimented with a Cinemag CMOQ-2S and a OEP A262A2E in my new diy LA-4 and I'm going with the OEP.

My point is this; In my opinion the OEPs are great on individual tracks but when it comes to sitting across an entire mix I find them too muddy/coloring and prefer more transparent kind of transformers. They're usually more expensive and I do hear myself referring to them as "better", more "high end" and so on. Don't know if that's correct by any standard but I'm pretty sure that the transformers' feelings aren't hurt by it. It just makes communicating about them a lot easier.

 

[Stagefright13]

I used ALL lundahls And am very happy. Big sound! I use it on a lot of stuff. Some things you prolly already heard...
Maybe not for everything but irresistible sometimes! I use it tons. 

 

[pstcho]

hi, i want to try without transformers because i have a lot with oep and i love it i have some with lundal and i don't use often it and i want to test without transformer with electronic symetrisation to have a diferent sound

 

[gyraf]

You can't really interface to the G9 circuit without output transformer - those are there to convert the tubes output impedance into something useable - and they provide an extra safety isolation from the HT voltage. Find another transformer type if you want to experiment with sound, but don't run it transformerless.

Jakob E.

 

[pstcho]

ok all right

i hoped there was a funny solution as just put a condenser in line with the output and a simple symetriser by op amp but no

then thank you i will not burn anything then

and than you Jacob for all what you do for us

David