Another DIY SS Amplifier with NVA Boards

[Daniel Quinn]

Semantics of no consequence to the point I made

[Lurcher300b]

Whatever

[_D_S_J_R_]

how I understand it:
Quoted: the less smoothing capacitors you will need
First it applies only to Docs design where main difference between amps is size of transformer and size of heat-sink
also the word need suggest minimum to operate correctly
and there is a difference between minimum and optimum
that's all on top of cost effectiveness that applied to all NVA

Tom, I don't think that's right. The larger amps (AP50 upwards) had double value supply caps over the smaller models and the Phono 2 has double that again (one lot in the PSU and the other set in the head unit).

RD told me early on that getting a larger reservoir was a good move, but maybe four 4700 rather than two 10000, but this may depend on the caps used?

[valvesRus]

you say you wish you never made the post

No I didn't, I said you should assume I didn't make the post, two different things.

I say DQ old chap, try reading the posts AND understanding them.

[SteveTheShadow]

What I basically said was that the type/make of power supply cap has an audible effect on the sonic presentation. This is a known phenomenon. The amount of reservoir capacitance didn’t enter into the argument.

I’m with Nick. Yes a big transformer can supply more “instantaneous” charging current to the cap bank, but the rate the amp attempts to drain the reservoir is to do with what is pulling at the cap bank from the other side, ie the demands of the music signal, not the mains transformer. Not enough storage and the power supply rails will sag under load, regardless of how big the mains transformer is, especially with a heavily class B biased output stage like this one.

The change in the treble response cleanliness and clarity is probably down to the higher quality caps in the power supply of my A60 clone; nothing to do with how much. Engineering wise, NVA amps arguably, are nothing out of the ordinary; I mean, current mirrors, power driver transistors and Darlington output stages are pretty conventional.

What is special about them is the results gained in terms of amount of work Richard put in over the years, refining the circuit in terms of component quality, bias settings etc, in both the power supplies and the amplifier circuit itself. They, without doubt, reproduce music to a superb standard and I considered myself lucky that Richard let me have a play around with the boards, when they were ostensibly his life’s work. I’m sure Stu feels the same.

I’ve found over the years that I have just enough knowledge to be dangerous, and that it is a universal engineering truth that anybody can build a circuit and make an adequate amplifier, but making a great one is an art; one that Richard had with the NVA circuit and Nick has with his own designs, Colin Wonfor et al.

[savvypaul]

you say you wish you never made the post

No I didn't, I said you should assume I didn't make the post, two different things.

I say DQ old chap, try reading the posts AND understanding them.

Your loyalty to Nick (and David Brook) is already understood.

Do you have anything to post that is relevant to the OP?

[valvesRus]

No I didn't, I said you should assume I didn't make the post, two different things.

I say DQ old chap, try reading the posts AND understanding them.

Your loyalty to Nick (and David Brook) is already understood.

Do you have anything to post that is relevant to the OP?

I did post that I may be interested in a pair of NVA amp boards if they become available once Richards affairs are sorted out.

So, the discussions re capacitor and transformer size are of interest to me.

[savvypaul]

I say DQ old chap, try reading the posts AND understanding them.

Your loyalty to Nick (and David Brook) is already understood.

Do you have anything to post that is relevant to the OP?

I did post that I may be interested in a pair of NVA amp boards if they become available once Richards affairs are sorted out.

So, the discussions re capacitor and transformer size are of interest to me.

All the more reason to stay on topic

[valvesRus]

Do you have anything to post that is relevant to the OP?

Does the same apply to DQ ?

Just asking.

[Daniel Quinn]

ADMIN EDIT - AD HOMINEM REMOVED