Choosing upgrades with new kit

[Lii audio fan boy]

Hi all, new to the forum but familiar with bottle head as had 2A3 monoblocks some years back used with 200hz tractrix front horns and compression drivers. Now I have Lii audio crystal 10 99db in tqwt. Thinking to build a 2A3 based amp but don't know what these upgrades do and whether they are needed. Interested to hear your experiences of this amp and improvements the upgrades made.

[Jay]

I have a Stereomour II which I use with 98 db speakers.  The DC filament upgrade definitely reduced the hum.  After a while, I added the stepped attenuator.  It improved the sound.  The background was "blacker" I'd say.  Both upgrades produced readily apparent improvement.

[Lii audio fan boy]

I have a Stereomour II which I use with 98 db speakers.  The DC filament upgrade definitely reduced the hum.  After a while, I added the stepped attenuator.  It improved the sound.  The background was "blacker" I'd say.  Both upgrades produced readily apparent improvement.

thsnks Jay, is hum an issue with these amps, I have owned several good valve amps i.e. Px25 300B and 2A3 but have been happy with a Sony solid state receiver that gives no hum whatsoever and sounds great. I am a bit concerned that hum may be an issue

[Paul Birkeland]

If you have very sensitive speakers (which it sounds like you do), then the DC filament upgrade will drop the noise floor down very low.  The attenuator upgrade will provide perfect channel balance and a bit better resolution compared to the stock volume pot and balance pot.  The Shunt Regulated Driver upgrade will uncork the performance of the driver stage and give a quicker, more dynamic presentation with a bit more open top end.

Your Sony solid state receiver and most solid state amps will employ gobs of negative feedback, so if you ever do come across one that produces hum through your speakers, that's a good sign that it's very near to a catastrophic failure.