Building an F5 Turbo v2 (in-Progress)

[PKI]

They are TO-220 but size is: 25.40mm x 19.05mm, the same as yours, 6L6.
Regarding thickness:
SP900 has 1.6 W/(mK) @ .23mm thickness
SP2000 has 3.5 W/(mK) @ .38mm thickness

So, Therm cond./pad: SP900 0.37 vs SP2000 1.3 in whatever units :-)

[PKI]

btw, why have you decided not to cascode?

[6L6]

Two reasons -

1) For illustrative purposes I am trying to build a V2 as close to the schematic as I can.

2) If all goes well, once the V2 is done, a cascode V3 will be made in the same chassis.

[PKI]

I see :-). It will be a very hot amp :-)

[AudioSan]

oh. i've missed this tread 6L6 you will reach the chassis max before the amp's max

with +/-32V and 1.9A bias(standar V2) thats about what that chassis can handle without external cooling of some sort.
for +/-45V+ even a monoblock will have broblems when you bias it up to "full" power.

[toxic ingestion]

6L6,

Any update on your build? Are you able to keep MOSFETs from shorting out?

Thanks,

Steve

[6L6]

I've only just received (in todays mail) some different parts to try again. There is a place for a compensation cap on the output boards, and I needed to get some of those to try. I am also going to a much bigger value gatestopper.

[Rixsta]

Hi, nice build
Is there any reason to use the Thermal pads over Mica & grease ?
ive had best results with the mica

[AndrewT]

There is one brand of Thermally conductive pad that significantly outperforms 1thou mica.

So far I have not seen any Members posting details of any competitor product that can match Keratherm's Kerafol 86/83.

If the others don't catch up quickly, they can only go broke.

[PKI]

Some experience about thermal pads:
we discussed earlier these two:
SP900 has 1.6 W/(mK) @ .23mm thickness
SP2000 has 3.5 W/(mK) @ .38mm thickness

To not be speculative I bought two of them and tried. SP2000 are much better pads. I do not trust my thermocouple from DMM in terms of super accuracy, but with SP2000 TO-247 case of F5 is about 5C cooler.