Preamp gain question

Your Bryston 4b has 30 db. of gain and your PV10 has 80 db. of total gain when you factor in the 48.5 db. of the phono stage. The amp/preamp gain interface is out of whack. Mismatches of preamp/amp gain are common, but this one is pretty extreme. Your phono cartridge also has very high output. The easiest way to deal with it is to use a set of the Rothmann 10 db. attenuators. I hear absolutely no sonic compromise using them. You could also have the preamp modified, at a much greater cost. If you carefully selected a lower voltage output cartridge, you could use more of the volume control. It probably would not require so drastic a gain reduction as going to a low output moving coil. Are you content with the volume control's range when using your cd player?

If you are looking for consensus, I agree with Photon46.

I think the Rothwells are an elegant solution for the money involved and that most folks with ordinary 'high fi' systems and are mere mortals here will will not detect their presence. If you have a highly resolved, synergistic system, properly set up, and you have a well trained ear, you could probably 'hear' them and anything else in the chain as well, but I think for most folks not so involved, these easy to use, cheap and reversable solution can't be beat.

BTW, be careful with the thought about changing the cartridge to a low output MC. You would in all likelyhood be posting thereafter about the low level hiss coming from your phono stage - and need to find the lowest low noise tubes to make it quiet again.

And, if we are wrong, you've only spent $70. There are other ways including the lowering of the phono stage gain or the pre-amp output gain, or even going to a medium output cartridge but the possibilities of Rothwell solving your problem without surgery is quite high.

Find out what the 'taper' of the pot IS.
Not all provide the same attenuation for the same amount of rotation.
The 2 types are 'linear' and 'logrithmic'(sp). Both start and end at the same place....say 10Kaohms to effectively 0, but have different ways of getting there.
You may get more resolution by going from a linear taper to log taper.

Magfan...All volume control pots these days are log taper. Linear would give ridiculous results. Actually, Log taper is a poor substitute for Audio taper which was used in the good old days. Evidently the low demand for Audio taper pots caused manufacturers to discontinue them.

Ouch! 80db of gain in the preamp, with a 6.5mv cartridge. I wonder if 10db attenuators will be enough to get the volume control into the optimal part of its range, where resolution is good, and perhaps even into the part of its range over which it can maintain channel balance accurately as volume is changed.

80db means a voltage gain of 10,000, so that if the cartridge is putting out 6.5mv (at 5cm/sec@1kHz, if I remember correctly what the conditions are at which cartridge outputs are normally specified), the preamp output with the volume control at max would be 65 volts!

Maybe 20db attenuation would be more appropriate. And I'd also suggest checking the specs on the preamp, particularly its maximum rated output voltage, to be sure it is really suitable for such a high output cartridge. My concern would be that with the volume control set say in the middle of its range, at 12 o'clock, that high amplitude signals would get clipped before they even reach the attenuators.

Regards,
-- Al