100W Ultimate Fidelity Amplifier

[xrk971]

Switching to 2SC3503 and 2SA1381 should work then?

 

[apexaudio]

Switching to 2SC3503 and 2SA1381 should work then?

Yes, and you can use +/-55V with 2SC3503/2SA1381 instead BD139/140.
Regards

 

[still4given]

Yes, and you can use +/-55V with 2SC3503/2SA1381 instead BD139/140.
Regards

+/-55v with 1P outputs? Are you serious?

 

[xrk971]

55v for a white knuckle experience 🙂 have fire extinguisher ready 😀

As Dirty Harry would say "Are you feeling lucky?"

 

[zoky2]

My FH-9 in An old ATX psu case with external power. Good sounding amp, better than gainclone which was before in that case.

regards
zoky2

 

[xrk971]

Nice heatsink! What's your PSU voltage?

 

[zoky2]

The PSU voltage is +-28V,because I use SMPS with original ATX trafo ,and this is the higest voltage you can get that way. Maybe once I will rewind trafo or I will try smps in post #7763.

regards
zoky2

 

[apexaudio]

+/-55v with 1P outputs? Are you serious?

Yes with 8R load.

 

[apexaudio]

My FH-9 in An old ATX psu case with external power. Good sounding amp, better than gainclone which was before in that case.

regards
zoky2

Nice work.
Regards

 

[xrk971]

Yes with 8R load.

If doing 53v should I change the BC546's for 2SC1845's?

 

[apexaudio]

If doing 53v should I change the BC546's for 2SC1845's?

No, you can use BC546.

 

[xrk971]

Ok I will build up a special high voltage version and see how it sounds.

 

[prasi]

53 volts! be sure to use a bulb tester and also stand clear for initial 'firing' up.
reg
prasi

 

[xrk971]

Really, safety goggles and all too 😀
Just having fun as no harm done when IRFPs can be had for $0.57 ea. 🙂

I have 63v electrolytic caps so not a problem there.

 

[apexaudio]

Ok I will build up a special high voltage version and see how it sounds.

I use F100 with +/-70V without problem.

 

[xrk971]

Ok - that's interesting how the BC546 can work like that. The rating is 65v Vceo max and wouldn't it see possibly 140v with 70v rails?

 

[apexaudio]

Ok - that's interesting how the BC546 can work like that. The rating is 65v Vceo max and wouldn't it see possibly 140v with 70v rails?

I use 2N5551 instead BC546 in F100 and LTP see single rail voltage only VAS can see possibly dual rail voltage.

 

[xrk971]

FH9 HV Edition

I just built another FH9 with components for 53v rails. 2N5551 instead of BC546 and 2SC3503 instead of BD140 and 2SA1381 instead of BD139. All power rail electrolytics are 63v, feedback cap is 1000uF 35v. All bypass 100nF bypass caps are 400v film. Will test tomorrow with fresh eyes. The only odd thing was that the 2N5551 had reversed pins so now flipped around. The BD's and SA/SC's are same pins.

 

[apexaudio]

I just built another FH9 with components for 53v rails. 2N5551 instead of BC546 and 2SC3503 instead of BD140 and 2SA1381 instead of BD139. All power rail electrolytics are 63v, feedback cap is 1000uF 35v. All bypass 100nF bypass caps are 400v film. Will test tomorrow with fresh eyes. The only odd thing was that the 2N5551 had reversed pins so now flipped around. The BD's and SA/SC's are same pins.

You can keep BC546 for 53v rails.

 

[still4given]

I use F100 with +/-70V without problem.

Yes, but F100 has 2 pair of outputs. You are not running at +/- 106v. I'm not saying it won't last for a short time but it is really stressing the SOA