HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

I think I probably know the answer to this but I will ask anyway . I have just purchased one of the B standard 20 passive pre amps off the new site which will be getting sent to me w/c 09/09 .

This is to match up with an NVA 20 power amp and I am sure it will be a great match . However a friend of mine has just passed on to me an Acoustic Dimension 41 stepped attenuator which I know is excellent and given that the improvement for the NVA passives is a stepped attenuator is it possible to open the 20 Pre and replace the volume pot ?

I know one the power amps the case is sealed and glued so very difficult to open as there is nothing to service and any issues would be a return to NVA for repair. I have never seen one of the Pre's so are they the same ?

Would love to add the Acoustic Dimension as it is a really excellent and transparent attenuator and would be loley to include it in the nice outer package of the NVA Pre that matches up with the power amp . However if it is just not possible then please let me know and I will consider just getting a case and making up a single input single output box for the Acoustic Dimension which is all I really need.

http://www.acoustic-dimension.com/index.htm

Opening the case isn't an issue at all, Doc used to do it all the time.

Fitting a SA is something I recall being asked before and Doc's response was that the case for the entry level devices was too small to house one. I'm sure you'll get the official answer from Savvy later though.

The P20 is tiny and although the little stepped attenuator that Tisbury use can almost certainly be fitted (I never tried it but it's small enough I think), the gain in very low level channel balance (without fiddling) may be countered by a (to me) slightly deadened presentation. Even the stock pot needed its legs trimming back to get inside the P20 case... That little film pot used really is a very good example of the type despite looks and cost.

Cancel the P20 order and see about a P50. Far more possibilities there and similar price to a 'new' P50. You also have a slightly added shielding luxury of SC cable from volume control to output sockets.

Oh by the way, the current P20's have the 'lid' inset into the bottom all round the case rather than the top on front and back, so removing said 'bottom cover' may well be more difficult without the chance of leaving a scar...

Will just let the P20 arrive and see what comes from that . I have very poor mechanical skills so I am not going to attempt anything that will damage the unit . Rather just keep it as it is and use it . Will make my own passive using the Acoustic Dimension donation which is a easy job anyway .

Nearly forgot which is rude of me , thank you all for your help and advice it is much appreciated.

Going by this page
http://www.acoustic-dimension.com/atten ... s-main.htm
there is no chance to fit it in P20
and just about enough space in P50 as you have around 50mm space to play with

It would comfortably sit in something like AP50/70 ;] but then most SA's would

Thank you for the definitve answer could anyone tell me what the psecifications are for a P80 Pre ? Is this still a straight volume pot or is it a stepped attenuator ?

P80 was an old model.

The current P90 has separate L/R pots and can be both pot or SA.

I bought a p20 in the current sale- bargain.
I have a p50 already- fine pre

The p20 is more compact and great for limited space but not a patch on the p50- to remedy this I replaced some of the signal wires with ssc I also ordered and I’m currently happy with it.