F5 Turbo Builders Thread

[Zen Mod]

in usual/common Papamp , pretty much everything is on same temperature ......... in other words - in 10C window

so , just clamp them to main hs

[AudioSan]

yes. i had a look at the diode data sheet. and the differece is marginal.
so there is no point in using external heatsinks.
as long as one is not going to push the bias to the limit

[Zen Mod]

same goal for every iteration ......... keep those heatsinks at 55C , max .....

no brainer .......... then .

[AudioSan]

i was thinking of bias and the point the diodes starts cunducting

[buzzforb]

Heatsink or no heatsink is solved or irrlelevant..... Just make sure you got an adequate heatsink. Here is my question. PLease explain this statement and how it relates to the ouput power of the amp.

"What if you remove the Source resistance altogether?
First off, you get the 44 amps. In addition, with Fets you get an output stage
that will deliver more Class A power at a given bias figure due to the square

law character of the Fets."

"The result is that the amplifier can now deliver 38 amp peaks"

First statement seems to suggest a cheat for more pure Class A, but the second seems to slip into the A/B category. Funny that he has addressed this very topic in another article, but equally funny that he has chosen to take his Pass amps in the dircection of more true Class A power.

[Zen Mod]

@AudioSan

another angle of same picture

[buzzforb]

So Class A is still Class A and diodes just allow full acces to given fets abilities, even if it is of a hybrid nature. Funny, all this talk of power, I was uncomfortable listening to single pair version. Of course i do not have proper multiway speaker and lsiten to silly FR stuff with woofers.

Originally Posted by gl

Buzz,

Which Maggie do you have?

I'm using 3.6's driven by AX100J's. Although I really like the sound I'm getting, you guys are starting to make me wonder, in an expensive kind of way, how an F5T would compare.

Let me say that I appreciate the encouraging way you all are sharing your results. Great work!

Graeme

1.6, but not mine.

[Zen Mod]

Originally Posted by buzzforb

....

buzz

context is very important .

just because of disregarding that , every F5T thread is at least 65% nothing more than noise

Papa was talking there about more class A in heavy (low ohmic) load

edit :

if one is not in need for hefty Turbo cojones , it's insane to build it

[gl]

I don't recollect hearing about these diodes being used in any Pass main line product. But then they haven't been including the "Fun Hardware Facts" section in the manuals for a long time. So who knows.

That being said the diode idea is particularly clever and is a real plus for smaller amps that need the ability to produce extreme current peaks.

Graeme

[Zen Mod]

yup

that's the very jewel of F5T article/project

everything else is "just" upping [voltage/bias/number of outputs] tutorial

Originally Posted by Zen Mod

I can't tell that entire article is revelation to me ( from several reasons ) , but I can tell that devil is in diode detail ......

so - I'm Happy ZM Camper