Resitor Passive

I used the PiaB with the RM10 as well and it worked very, very well, but I didn't have the K&K at the time. You should call Roger to hear his side of the attenuator versus TVC approach, the fella at Goldpoint said pretty much the same thing and it seems to make theoretical sense, and it sure worked in my system. Interesting, Roger also makes an RM4 or 5 preamp that has a built in phone stage and operates as pure passive for a linestage, same potentiometer as the one in the PiaB (a 1960s Noble that Roger said would be too expensive to make today). That being said, I think there is some consensus that John Chapman does great work and his TAP is among the very best passives available -- On the other hand, if your thinking about the RM10 you might want to investigate Roger's preamp.

I'm wondering if there is some synergy between the PiaB and the RM9 that Roger is exploiting? I am thinking of getting an RM10 and if I do may experiment with the PiaB.

On the other hand I've also been chatting to John Chapman about getting the new Bent which he will customize with a built in phono stage circuit that I will supply him with.

Decisions, decisions...

I went back and forth with the resistor-based PiaB and the TVC with SB102s and for my ears, in my system I preferred the resistor based volume control - which I was not expecting since the consensus seems to be with the TVCs. While the consensus is in favor of TVC, Roger Modjeski who makes my amp (RM9SE)is clearly in favor of keeping transformers out of the volume control thinking they cause more problems than they solve. I suspect that in the right combination, simple, high-quality attenuators provide a purer connection to the source.

I'm pretty sure that Jud Barber uses a certain Alps pot. In my LA-150 (version II) the manual said "it was not the highest quality, but it did sound the best".

-Jake

I don't know. The Pot-in-a-Box is Noble - same one used in the ARC SP6 back in the old days. Extremely expensive if manufactured to those standards to day, but I have no idea if, and to what extent, this makes a noticeable difference; of course, I have 50 year old ears.

Just curious, do you know if Jud Barber uses Alps or Noble volume pots in his preamp designs? I thought my Joule had Noble pots, but I can't remember.

I will be trying a TVC (S&B 102 MKI), Music Reference Pot-in-a-Box, and my Joule 150MKII driving high impedance and sensitive amps (CAT JL2, Music Ref. RM9MKII). I once had the Placette passive, but inthat case I clearly preferred the Placette Active (no gain stages, just robust buffering for an incredible 10 ohm output).

I would say "blow away" is a harsh term. I have participated in and side with the view that TVCs are better than resistor based passives. Maybe in some systems these "blow away" comparisons could be true, but the opposite could easily be true as well. I would say impedance matching is less of an issue with a TVC, which is very important when using any type of passive. In my system a TVC worked better from an impedance perspective and performed better than any resistor passive I have tried. However I have not tried them all, especially the Placette or First Sound, which are among the best from what I have read (funny Guy and Emmanuel both feel their active preamps are better).

Attenuators and their implementation are very important no matter whether it is in an active or passive preamp. I am now using an active preamp with premium 45 step Shallco volume switches, but the 19 step Seiden switches in my TVC were no slouch either. Funny though how my Joule LA-100 MkIII did just fine with basic dual volume pots.

As you know Roger's pot in a box uses a 40 year old switch with great results. Some also swear by the Penny & Giles, Gold Point, and DaCT switches. Intact Audio sells custom switches for their autoformers (a custom version of which will be used in the new Bent TAP from what I have heard). The possibilities are endless.

What will be more interesting to me are your observations as you try these options. Please let us know what you think as you have had the opportunity to hear many excellent active and passive preamps in your system.