Bottlehead Forum

Bottlehead Kits => MonAmour => Topic started by: Altecboy on October 29, 2021, 11:38:57 PM

Title: By-pass/replace the 47uF Cap
Post by: Altecboy on October 29, 2021, 11:38:57 PM
I like boutique capacitors.  I've switched the 0.1uF and 12uF (I used 10uF) coupling caps to Auricaps.  Of all the caps I've tried in my speakers, line buffers and tube amplifiers, these seem to be my favorites.

My output tube cathode capacitor is presently the stock Solen.  For whatever reason, I'm not a Solen fanboy. I'm aware that in other designs, folks use even electrolytics in this position.  Even so, I'll rest easier (for about 10 minutes) if I improve on the Solen.

Has anybody tried by-passing this with smaller caps?  Tried a different mfr to good effect? 

thanks for any input.
Title: Re: By-pass/replace the 47uF Cap
Post by: Doc B. on October 30, 2021, 05:45:03 AM
Folks use electrolytics in that position as a cost saver, not for the sound. If you like the sound of Auricaps that is as good a reason as any to try one there.
Title: Re: By-pass/replace the 47uF Cap
Post by: Altecboy on October 30, 2021, 07:46:45 AM
Thanks Doc.
Any thoughts on bypassing the Solen?  The Auricaps of that size run $100/pop.
best regards.
Title: Re: By-pass/replace the 47uF Cap
Post by: Paul Birkeland on October 30, 2021, 08:05:36 AM
  The Auricaps of that size run $100/pop.

Bypassing is extremely inexpensive.  I would suggest giving it a shot to see how much of a different it makes.

Film cathode bypass caps in SET amps are incredibly rare, so you may also find it helpful to remove the Solens and downgrade to electrolytics to understand that difference as well.

Title: Re: By-pass/replace the 47uF Cap
Post by: Altecboy on October 30, 2021, 11:37:55 PM
Thank you PB
Title: Re: By-pass/replace the 47uF Cap
Post by: Altecboy on November 24, 2021, 02:45:41 AM
So I went ahead with the cap replacements.  All Auricaps.  First I replaced the 0.1uF coupling cap. The change was immediate and, in my view positive.  Smoother, richer.  After two weeks I replaced the 12uF coupling cap.  Same deal: immediate improvement.  Several weeks later I replaced the bypass cap.  Initially awful.  Dull, recessed.   After several weeks an overall improvement.  That one was the only one that really needed break-in.  I'm done. 

It was worth the effort and expense.