[Voodoochile]

Hi Kevin- I, and I'm sure many others, have been noting higher voltages when matching up transistors for the Dynamic amp.

As an example, I just finished sorting through about 110+ (NPN)2sc1815's. The distribution of values is like this:
30% 11.94v
30% 11.95v
30% 11.97v
and two or three each of other various values, with a low of 11.91v, and a high of 12.02v.

EDIT: These transistors are from two different lots, FWIW.

Your article says approximately 10-11v, which granted is a fairly wide range. 90% of mine are within better than a tenth of a volt of each other- but all are almost a full volt above the range spec'd. I measured the voltage with my DSO, as it's more accurate than my DMM, and am using an Agilent linear bench supply at exactly 16v. The resistors in the jig are matched to within .1%. Of course I do not have a curve tracer, and it's making me crazy.

What does this mean in terms of supply voltage to the amp, if anything? I realize this means 'more voltage gain', but should any accommodations be made for this elsewhere?
Should I just start drinking a few pints and forget about it?
I don't believe I can get past this, otherwise.

edited to reflect that this is referencing the Dynamic amp, not the KGSS

 

[Arzela]

Previous posts show the 1815's
are nominially 11.95 volts.

It also seems the 1015's are nominally
4 volts, approximately.

 

[Voodoochile]

With the 1815 being a high-frequency amp, and being ~1 volt higher in gain than KG's original spec;
and the 1015 being a low-frequency amp, and being ~2 volts under KG's original spec, I wonder what this does to the character of the sound?

The ~1v NPN discrepancy is less than 10% of the spec, but the ~2v PNP discrepancy is 33% of the original spec.

In other news, at least the readings are consistent!

 

[alsq]

voodoo: I have a similar problem. Do you
have any follow ups info?

 

[Voodoochile]

Hi-

They are fine so long as the voltage reading matches each other as closely as you can get.

What does matter quite a bit is that you get transistors from the same grade. Grade GR is nice, but most any grade will work so long as both the NPN and PNP transistors are the same grade. I have also used grade Y.

And of course that the voltage you measure matches within each type (pnp or npn).