Steremour 2A3 louder than Paramount 1.1 300B, eh what?

rbc3 · 3743

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Offline rbc3

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I'm scratching my head over this one and trying to figure out an explanation.  Here's my setup

Astell & Kern AK120 DAP via Toslink -> Schiit Bifrost Uber DAC -> amp -> Seas Pendragon speakers

When I switch between Stereomour 2A3 and Paramount 1.1 300B the max volume I can get out of the Stereomour is much higher than the volume when the DAC is plugged straight in to the Paramounts and I can't figure out why.  I'm not complaining that I don't get enough volume out of the Paramoun, just trying to understand how a 300B amp rated at 8.5W is not as loud as a 2A3 amp rated at 3.5W all else being equal.

The Stereomour is almost completely stock except that it's a 220V version that I'm running off of a step up transformer to switch up the standard US voltage to 220V (it's running at more like 240V).  The only other mod is that I have installed the impedance switching kit in the Stereomour and it is switched to 4 ohm and balanced out to match with the Pendragons which are rated at 4 ohm.

The Paramount 1.1 are almost completely stock.  I have upgraded the RCA jacks to Vampire gold plated solid copper, the speaker binding posts to Cardas gold plated solid copper, and the 4 pin sockets to gold plated solid copper bakelite.  Plus there are resistors (don't know the rating because the Paramounts were built by the team and Bottlehead) across the ground bus to each of the positive and negative speaker binding posts, which improves the bass from what I understand.  Also the OT have been tapped at 4 ohm to match the ratings of the Pendragons.

I've tried playing around with a number of 2A3 tubes the Stereomour as well as different input tubes and 300B tubes in the Paramounts, but the results in volume levels are about the same.  The Stereomour always wins and setting it at about 75% on the volume pot gets it to about the same volume as the Paramounts straight off the DAC.

Any thoughts?

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120


Offline Paul Birkeland

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Reply #1 on: May 16, 2015, 09:01:30 AM
This is simply a matter of power vs. gain.  The Stereomour is an integrated, so it has higher gain.  The Paramount 1.1 is a power amp, with lower gain, which may benefit from a preamp depending on the source voltage available.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline rbc3

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Reply #2 on: May 16, 2015, 09:48:35 AM
I guess I assumed that the Stereomour's volume pot and input switch were passive so it didn't increase the gain on the input.  I was thinking that some day I'd like a BeePree to go with the Paramounts, so I'm sure the combo is much more powerful than the Paramount with a passive pre.  Any other thoughts to bump the gain while minimizing the coloration of the sound going in to the Paramount?

Robert C

Paramount 1.1 300B, Tekton Design Seas Pendragon, Stereomour 2A3, Omega Hemptone 8, Acoustic Signature Challenger Mk3, JMW 9T, Dynavector XX2mkII, Clearaudio Balance, Quickie 1.1, Schiit Bifrost Uber, Mainline, Audeze LCD2.2, AKG K1000, HiFiman HE-500, Sennheiser HD650, AK120


Offline Paul Birkeland

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Reply #3 on: May 16, 2015, 07:52:40 PM
I guess I assumed that the Stereomour's volume pot and input switch were passive so it didn't increase the gain on the input. 
They are, but again, the Stereomour has higher gain than the Paramounts. (The 12AT7 has a higher amplification factor than the 5670) 

Oddly enough, the DAC you have should provide enough voltage to get all the power out of your Paramounts.  It might be a good idea to do a voltage check in your Paramounts to be sure everything is operating properly.   

Both amps can be pushed way beyond the power ratings we publish, but with an increase in distortion.  This may also play a part in what you're hearing. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man