Bottlehead Forum

General Category => Technical topics => Topic started by: Bonzo on April 17, 2015, 04:35:11 AM

Title: Quickie Output Coupling
Post by: Bonzo on April 17, 2015, 04:35:11 AM

Ok!
I've found a pair of UTC A20...
I know they can't stand any DC, but do you, Master Technician of Bottlehead Forum, think I can use them as coupling transformer in my Quickie?
Just to explore :-)

Title: Re: Quickie Output Coupling
Post by: Paul Birkeland on April 17, 2015, 05:58:05 AM

The A-20 is a 600:600 Ohm line transformer with lots of taps on both windings.  This is not suitable for the Quickie.

Title: Re: Quickie Output Coupling
Post by: Bonzo on April 17, 2015, 06:14:28 AM

Quote from: Caucasian Blackplate on April 17, 2015, 05:58:05 AM

The A-20 is a 600:600 Ohm line transformer with lots of taps on both windings.  This is not suitable for the Quickie.

 :-[
ouch!

So I sick with the original project: to substitute Edcor 10k:10k transformers in my diy dac  :)

Thank you and sorry for my dumb question!

Title: Re: Quickie Output Coupling
Post by: Paul Birkeland on April 17, 2015, 06:24:49 AM

It's not a dumb question.  Are you looking for balanced outputs, or lower impedance outputs? 

I think 10K:10K is even a little low for the Quickie, but there are others that will work well running 15K:15K, or even higher (they just cost as much as the Quickie, or more!)

Title: Re: Quickie Output Coupling
Post by: Bonzo on April 17, 2015, 07:57:20 AM

I was thinking of a quick wat to test the transformers and to compare capacitor and transformer coupling.
But what you wrote is right, output transformer aren't cheap, and output transformer for line level preamp are outrageous expensive (like the ones for Euridice diy preamp).
Well, changing subject, what about a battery phono preamp to match the "Quick*" serie?

 ::)
 ;)
 ;D

Title: Re: Quickie Output Coupling
Post by: Paul Joppa on April 17, 2015, 08:05:33 AM

I've looked into a battery tube phono preamp several times, and have not yet come up with anything I'm happy with - between the microphonic issues and the low gain of available tubes (causing many tubes and more battery drain). But we'll keep going back to the issue.

Title: Re: Quickie Output Coupling
Post by: Bonzo on April 17, 2015, 08:20:20 AM

Wow...
I can only say wow...hope this dream come true soon
Keep the good work!

Thank you!

Title: Re: Quickie Output Coupling
Post by: Paul Birkeland on April 17, 2015, 08:37:17 AM

Quote from: Bonzo on April 17, 2015, 07:57:20 AM

I was thinking of a quick wat to test the transformers and to compare capacitor and transformer coupling.
But what you wrote is right, output transformer aren't cheap, and output transformer for line level preamp are outrageous expensive (like the ones for Euridice diy preamp).

If you like the Euridice, you'd probably enjoy the Mainline.

Title: Re: Quickie Output Coupling
Post by: Bonzo on April 17, 2015, 09:27:07 AM

Mainline you said? Isn't Mainline a headphone amp only?

Title: Re: Quickie Output Coupling
Post by: Paul Birkeland on April 17, 2015, 10:05:47 AM

Yes, it is a headphone amp.  It has the transformer coupled single gainstage topology similar to the Euridice, but with a shunt regulated power supply, parallel feed outputs, etc. etc. (and more power!)