F5 power amplifier

[steve jones]

Hopefully a few quick questions. I'm a Neanderthal with SS stuff (still learning to walk upright I guess).

Gathering parts to build a pair of F5s to use with my Altec Model Nineteens.

I've received 2 pair of 2SK170 and 2SJ74 BLs matched at 6.7mA Idss.

Nelson just mentioned 8mA. Do I need to juggle any resistor values on the schematic to use what I've got, or is the Idss value not that critical to its circuit requirements?

Also, for the 0.47 and 100 ohm resistors, are non-inductive required (if wirewounds are used)?

Thanks,
-Steve

[Zen Mod]

Originally posted by steve jones
.........
Nelson just mentioned 8mA. Do I need to juggle any resistor values on the schematic to use what I've got, or is the Idss value not that critical to its circuit requirements?

Also, for the 0.47 and 100 ohm resistors, are non-inductive required (if wirewounds are used)?

Thanks,
-Steve

there is no need to alter values of resistors;

non inductive can't harm , but they aren't so critical ; at least in my book .....

use whatever you have now ; later you can go for fancy ones

[Nelson Pass]

Originally posted by steve jones
I've received 2 pair of 2SK170 and 2SJ74 BLs matched at 6.7mA Idss.

Nelson just mentioned 8mA. Do I need to juggle any resistor values on the schematic to use what I've got, or is the Idss value not that critical to its circuit requirements?

If by chance you find yourself short on bias, you can raise the
values of R3 and R4 (or even eliminate them) to develop enough
voltage to get the bias current you want.

[steve jones]

Thanks to both Zen Mod and Nelson for the help and advise.

[Zen Mod]

Originally posted by steve jones
Thanks to both Zen Mod and Nelson for the help and advise.

who's Nelson ?

[steve jones]

I only know of two Nelsons.

One is Mr Pass.

The other is:

[nicoch58]

Orazio Nelson ?

[zeonrider]

You forgot this man!

Regards zeoN_Rider

[Nicola]

Argh, the postman is putting his life at risk, i haven't received the April release of AXP yet. Would anybody accept to mail me a scan or when might it be available under FirstWatt ?

Has anybody already commented on how it sounds ?
Thanks

[Nelson Pass]

Very difficult without your address.