F5 power amplifier

[Neutrality]

Originally Posted by bear

Neutrality, fyi your questions have been raised before in this thread, and a number of variations and approaches to the PS have been discussed... you might want to search or browse back into the thread?

Imo, the use of an opamp if you have a high resolution system might obviate the benefits of the F5's minimalist approach.

Any means including a single FET as a phase splitter out through a multi opamp "instrumentation" type configuration or a transformer could work.

Others might want to express other ideas or approaches, this is just me making noise...

_-_-

I know, been reading alot of this thread, but 750 pages is alot.

As for having a high resolution system, I dont, using an old NAD surround receiver as pre amp, blasphemy to even think about using it with a F5, I know.

[bear]

I know - try the "search within thread" at the top of the thread... works pretty good...

Since the F5 is low gain you can go direct from your CD player and get rid of a distortion producing box in the process...

_-_-

[massimo]

Why going balanced if your source is single ended only?
A PS for balanced F5 requires 4 times the current @ 24V... People lower the voltage to stay with reasonable current.
Best converters? Xfrms, of course! But the very good ones are scarce and $$$$
My 2 c: start with a std F5 and.... enjoy!

P.S. the 8 x 0R47 (4+4) form a RC filter with the second cap(s). This helps to reduce noise in the pw supply.

[jacco vermeulen]

Originally Posted by bear

How about, How about ?

How about a Triac switch, the fashion of the late '80s ?
(mmm, or just solder a burn-safe resistor across the fuse box leads)

I like a Gershwin tune. How about you ?

[Neutrality]

Originally Posted by massimo

Why going balanced if your source is single ended only?
A PS for balanced F5 requires 4 times the current @ 24V... People lower the voltage to stay with reasonable current.
Best converters? Xfrms, of course! But the very good ones are scarce and $$$$
My 2 c: start with a std F5 and.... enjoy!

P.S. the 8 x 0R47 (4+4) form a RC filter with the second cap(s). This helps to reduce noise in the pw supply.

Im quite satisfied with the output power in class A but I want some more power into Class AB, it is nice to have a little power in reserve.

[tinitus]

Originally Posted by bear

How about a 10 amp fuse?
An 8 amp?
ok 7 amp... 5?

I have had a burned amp
Printboard was literally in flames

But that didnt blow the fuse
Big trafos, big fuses
Could be a problem

Question is whether its just a fake safety

[DougL]

Originally Posted by bear

Mmmm... DougL are you suggesting that i need to "upgrade" my supply? Nah. (best check my website, fyi) But thanks for the suggestion. ...

Bear,

No offence intended.

You are on my personal list of luminaries for DIYAudio. Impressive site BTW.

My personal dogma is that things like fuses "should not" affect sonics.
If they actually do affect sonics, there "should be" a way to correct it in the power supply design.

I do like the breaker idea.

Peace

Doug

[bear]

DougL, thanks for the kind words. I assure you I am not a luminary, just an idiot savant, heavy on the idiot most of the time I can assure you. Ask anyone who actually knows me... my personal dogma is that nothing should effect sonics, but apparently almost everything does. Therefore things are weird and I leave it at that and just accept it.

Breakers have problems too...

The good thing about a class A amp is that the current draw is the most constant of all analog amplifiers, so the effect of the fuse is that it ought to have the least effect (one would think).

I like the idea of a multi contact relay as the power switch, designed so that it will open in the event of a fault condition - to save the house, not the amp.

Of course that gets complex and maybe is more complex to execute so that it works right than the whole entire two channels of F5. Kinda defeats the purpose?

So, at minimum, fuses are definitely required in the AC mains to protect from catastrophic failure and resulting fire.

(just in case anyone was unsure)



_-_-bear

[awc]

fuses are definitely required in the AC mains

Yes But, to avoid the "possible" degrading of signal make them short, and use silver ones,
Ive even read somewhere years ago that, ceramic affect the signal less, and I have used that approach along with the silver ones,
and never been able to tell the difference with my ears, but it makes me, feel better about my sound system. examples available: Xindak Silver Fuse For Audio 2A. also HiFi-Tuning Silver/Gold fuse, 2A, slow blow, just do a search on ebay "silver fuse"

[Blues]

Literally and figuratively it's about $30 a pop!