F5 Turbo is posted

[Bigun]

wow, 100W Class A - that's huge !



nice to see the P3 harmonic adjustment - I used the same kind of thing (TGM goes tubey thread) before and can testify that it works but I expect it's much better with Class A than trying this in Class AB.

 

[ra7]

I have FQP19N20 the TO220 version of the FQA
Current is nearer to the counterparts

They have been running since August and no problem so far.

They are still avvaliable evveriwhere.

How did you mount them to the heatsink? That TO-220 case looks weird. How many watts are they dissipating?

 

[geraldfryjr]

This is too Cool !!!

After seeing some specs, I so want too build a set of these!!

It looks as if that they fill my requirements of at least 40Vpeak and into 1 ohm peaks as well for driving my DIY ESL's.
With a very simple circuit ,few parts and great specs to boot!

I already have a few large transformers in the 1000VA range that will work.
Just need to get the semi's and some very large capacitors and some sort of heatsink system,I have a liquid cooled type in mind maybe.

It will be awhile before I build a monster version but I will now start with the basic F5 though, as I was thinking about the AlephJ-X as well.

Thanks, Nelson Pass !!!

Jer 🙂

 

[Sangram]

For the JFETS, eBay seller "alweit" has well-matched pairs. Highly reccommended seller!

eBay - See alweit's JFETS here

🙂 Thanks.

Any idea if I can get the Fairchild output devices any more? I do have one set (unmatched) of the input pair but no output devices.

I assume with all the banter that any high-speed diode with a decent current reserve will do for the output stage.

 

[Zen Mod]

🙂......

I assume with all the banter that any high-speed diode with a decent current reserve will do for the output stage.

decent current , appropriate U/I characteristic (read -voltage sag at said current)

 

[bifi]

Fairchilds

Digikey and Mouser marked the Fairchilds as Discontinued / Obsolete

 

[Sangram]

^^Of course 🙂

Thanks so much!

 

[jacco vermeulen]

eBay seller has well-matched pairs.

1-2 % is "well" matched ?

 

[EUVL]

Better than not matched at all, Jacco.

🙂


Patrick

 

[jacco vermeulen]

True, merely found the mentioned 2%, 1%, and 0.02mA amusing.

 

[triode_al]

True, merely found the mentioned 2%, 1%, and 0.02mA amusing.

I used his JFETS and the drain resistors have been set within 3 ohms of each other. 😀 That means: 0,5%, including 'serving' the matched outputs. Not bad . .

 

[sekess]

IR outputs

Is there a good source for IRFP240PBF's and IRFP9240PBF's that you guys are using?
and

Is anyone still offering matched output devices?

Thanks,
Steve

 

[barry_e]

F5 Transistor kits

I just emailed "Hannes" last night and he said he is matching some more (in Austria) and will have them in a few days.

He goes by "h_a"

Please See: http://www.diyaudio.com/forums/swap-meet/178924-f5-amp-transistor-kit.html

Barry

 

[Bksabath]

🙂 Thanks.

Any idea if I can get the Fairchild output devices any more? I do have one set (unmatched) of the input pair but no output devices.

I assume with all the banter that any high-speed diode with a decent current reserve will do for the output stage.

If FQP19N20 instead of FQA19N20 is some you can use I got about 80 spare
and 80 FQA12P20

Just PM

 

[bobodioulasso]

BTW, i see no 10uF decoupling cap in the picture of F5 turbo from the PDF.

 

[Nelson Pass]

The decoupling caps are optional in most cases, where they make a small
improvement in the square wave, but they may become more necessary as
the size of the amplifier is scaled up.

😎

 

[fdlsys]

Thank you very much Bksabath, I will try that.

 

[Bksabath]

How did you mount them to the heatsink? That TO-220 case looks weird. How many watts are they dissipating?

Same as i did for the TO247 or even the toshibas
Big piece of flat coper bar and 2 M4 (metric 4mm) bolts on super duper heat spreaders.

32V 1.3 A or 26 V 1.8A depending on the mood I got 100VA trafo with taps at 20 and 24 V
About 160 watts on each sink and recon they shuld be good for around 250 W whitout going over 50 C mark.

I am using Kerafoll 86/83 and with the bolts I can put loads more pressure on them than with litle M3 single srew.

Kerfoll show graph of thermal resistance against pressure on data sheet.

Loads more about it on MY F5 tread.
The grey wire in the first picture is a PT 100 probe I have used to monitor the TO220 case themperature
If you post there I will be happier to ansver any question you have witout boring soks off the rest of the population and hi jack this tread.

 

[labjr]

Anyone know if Linear Systems started making the LSK170 LSK174 JFETs? I remember reading something about it a while ago.

 

[Loudthud]

Apparently Fairchild obsoleted that die in the TO-3P package. The same die is available in TO-220 as FQP12P20 and FQP19N20.