bernbrue

Testing some AVD Audio input and output transformers
« on: April 11, 2017, 07:40:51 AM »
Hi,
I've got some nice transformers from forum member Andrej (AVD Audio) here and did some measurements and tests. I'm very pleased by the built quality and how they perform.

All tests were done out of circuit. I've just inserted the transformers in one of my ADT-5MT consoles channel strips and measured with RMAA.

Part two will be in circuit (Varimu compressor triode push pull circuit) in comparison to other candidates from Edcor and Sowter. I'm going to attach some PDF files and pictures later.
Cheers
Bernd
« Last Edit: April 11, 2017, 10:39:50 AM by bernbrue »


L´Andratté

Re: Testing some AVD Audio input and output transformers
« Reply #1 on: April 11, 2017, 08:59:51 AM »
Hi Bernd!
Thank you, that´s very interesting!
Have you also measured pri/sec inductance?

Sadly there´s no data sheet on this part... ;)

Strictly amateur since 1973...

bernbrue

Re: Testing some AVD Audio input and output transformers
« Reply #2 on: April 11, 2017, 09:04:25 AM »
No, I've only measured primary and secondary resistance. I'm not so familiar with measuring inductance.
All I can say so far is that they sound amazing.
Bernd
« Last Edit: April 11, 2017, 09:08:07 AM by bernbrue »

bernbrue

Re: Testing some AVD Audio input and output transformers
« Reply #3 on: April 11, 2017, 10:40:52 AM »
PDF attached, see first post as well.
Bernd

avdo

Re: Testing some AVD Audio input and output transformers
« Reply #4 on: April 11, 2017, 11:37:26 AM »
Bernd, hello!
I'm happy to see you have received this already!

L´Andratté, about pri/sec inductance:
I checked it when I did it. Pri inductance is around 24H. And I dont remember about Sec. (Think around 5 or 6 Henries)

One I did with GAP. But with same Pri induction. Second one, output transformer with %HiNi laminations. I did same for my friend with Ni lam for out LA-2A. And transformer has a best characteristics. Small THD for 100k load impedance on input.



Very interesting to hear new comments from you! Will wait!

Thanks!
« Last Edit: April 11, 2017, 12:26:28 PM by avdo »
________________________________________
AVDAUDIO store in AVDAUDIO.COM!

bernbrue

Re: Testing some AVD Audio input and output transformers
« Reply #5 on: April 11, 2017, 01:03:33 PM »
Here are the results of my "in circuit " test. It's a 436 style varimu triode push pull circuit.
Bernd

rackmonkey

Re: Testing some AVD Audio input and output transformers
« Reply #6 on: July 10, 2017, 02:12:14 PM »
I've used these (both the 2622 and 2503) in some 312 clones I built and can attest that I've been very happy with them. I've built units with Ed Anderson's 2622 and old Jensen JE-123-As and I thought these compared quite nicely. Some subtle differences but very nice all the same.

I have frequency response tests of them both in the google drive folder I shared out in a Chamber post recently, FWIW.

Nice work, Andrej!
Whether you think you can or you think you can't, you're probably right.