Bottlehead Forum

Bottlehead Kits => Stereomour II => Topic started by: faskenite on July 05, 2018, 08:42:15 AM

Title: Now To See If It Works
Post by: faskenite on July 05, 2018, 08:42:15 AM
Just completed, resistance checks passed.  Getting my rubber soled shoes on and sticking my left hand in my pocket for the voltage checks!
Title: Re: Now To See If It Works
Post by: Jay on July 05, 2018, 10:59:15 AM
looking good!  You'll love the sound.
Title: Re: Now To See If It Works
Post by: faskenite on July 09, 2018, 04:17:16 PM
Passed the voltage checks, up and running.  My manufacturer bias has to be taken into account, but in these early days I am very impressed.  Previous main amps have been by Manley and Wavelength, but this thing is something different.  I confess that I substituted quite a few parts, but I am sure that what matters most is the fundamental design.  And this is the quietest tube amp I have ever had in the system!  Initial impressions are that detail and flow are entirely different from what I have experienced previously.  But I think the main point has to be that this thing sounds great.
Title: Re: Now To See If It Works
Post by: Jamier on August 03, 2018, 04:44:10 PM
What parts did you you replace? And you did not try it with the stock parts first?

Title: Re: Now To See If It Works
Post by: faskenite on August 04, 2018, 06:58:48 AM
Thanks for the interest!  For a long time I have wanted to try a 2A3 SET amp in my system.   I have previously had a 300B stereo amp and 300B monblocks (2 per side, switchable from single ended to push pull).  I have been in this hobby (Hi-Fi, not DIY) for a long time and wanted to put together something I thought might be extra nice.  So my changes do not reflect any degree of seasoned electronic wisdom, but rather the choices of a fairly hapless hi-fi enthusiast picking things he thought might be nice, or at least fun, after doing some research.
On the top I used Mullard 12AT7’s that I have had but have not used for a long time.  Years ago they were used in a full function preamp.  They are exceptionally quiet and sound good.
I kept the stock Sovtek 2A3’s, although my past experience with Sovteks has not been great. ( To say nothing of those Russian ‘Gold Lion’ 300Bs, although I may have just had a bad batch - I replaced them with Emission Labs, which are great.)
This was my second DIY project, after building the Quickie last winter.  While building said Q I screwed up some RCA soldering and in trying to undo my error pretty well munched one of the stock RCA’s.  This time I decided to use something I thought could be more robust (and silver!) so I got some Audio Note RCA’s. 
I have always liked the Cardas binding posts on my 300B SET so I got some rhodium (silver!) ones for this project.
On the Quickie I used an Audio Note volume control which I like, so I used one of those here too.  The balance and selector controls are stock.
Down below I went a little cap crazy.  Jupiter HT’s for the 3.3 caps and V-Caps for the 1.0 uF’s. 
For reasons that probably defy rational analysis I used Duelund and Neotech solid core copper hook up wire. I used the stock green wire from the power transformer.
When wiring the RCA inputs the supplied Cat-5 wire pretty much got the best of me.  So for two of the three inputs I used twisted pairs of the Duelund and Neotech.  In the result those inputs are very quiet, and I think they have a fuller and richer sound than the Cat-5 input.  But I have not spent a lot of time on the comparison.
I don’t think I have forgotten anything.  This amp sounds great.  Quietest I have ever had in my system (music is almost 100 per cent vinyl, currently with Lowther Medallions, so if there is noise you’ll get it - they are supported by an REL sub).  I am eyeing Emission Labs mesh 2A3’s but with no urgency whatsoever. I am enjoying this amp too much as is.
I’ll post a pick of the innards later, can’t do it from this iPad.
Title: Re: Now To See If It Works
Post by: faskenite on August 04, 2018, 12:12:04 PM
The innards:
Title: Re: Now To See If It Works
Post by: Sugar Man on August 09, 2018, 11:21:53 AM
Looking good! Those VCaps are famous for needing a long break-in period...:o