Peavey Megabass- why?

[drewl]

Oh Peavey, with hundreds of well designed models using proven bipolar designs, why did you have to jump on the trendy at the time use of mosfets?

Signal goes into power amp and doesn't come out.
Even the power amp design physically is a pain, a giant block of metal pieces connected together, with a board on top, ugh.

[x-pro]

Oh Peavey, with hundreds of well designed models using proven bipolar designs, why did you have to jump on the trendy at the time use of mosfets?

A class D amplifier is better with mosfets.

[glebert]

Wasn't Peavey a bit ahead of most in using class D for bass amps? I believe the Databass was class D and that was 35 years ago. Unfortunately they must have seen class D as good for high efficiency, but they never figured out to make them light. Even the recent Max amps (which I'm a fan of) were class D power amp but still had traditional transformers for the power and heavy particle board boxes. I don't know if the newest have fixed that.

[drewl]

Yeah, it's heavy!
Anyone know of modern replacements for the fets?
Irf230 n channel and rfm10p15 p channel
They're enhancement mode, so I don't think I can use regular power fets.

I suppose I can try eBay etc.

[Greg Robinson]

They're enhancement mode, so I don't think I can use regular power fets.

Regular FETs are enhancement mode (normally off), it's depletion mode (normally on) that are the unusual type.

Avoid eBay for active devices unless you're very careful finding a reputable seller. Expect everything will be fake, even if it comes from a "US/UK/AUS" whatever seller - it'll probably just be dropshipped from China.

[drewl]

That's what I figured
Unless I can find some old ones.
I have T03 case BUZ901/906 but they're a different pinout

I was going to try a couple TO247 package fets just to see if the rest of the power amp is okay
It also blew the 1N4744 15volt zeners that I read about in another thread here.

[The Dude]

FWIW: I did a little searching and found these:

Dalbani pulls (I've had good luck with these- OEM parts and tested)

https://www.ebay.com/itm/12479937709...Bk9SR7azmYbGZA

Ruby Tubes site, although it doesn't say for sure if they have stock.
https://rubytubes.com/products/peave...icakDSjycmVNUN

Expensive, though!

[drewl]

Yikes
Yes they are expensive
Thanks for the finds!

[drewl]

Forgot to mention, this customer has TWO of these

[J M Fahey]

With careful lead bending you can usually mount cheap and plentiful TO247 case MosFets , say IRFP240/9240 replacing unobtanium metallic TO3 types.