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    Building, troubleshooting and testing of these amplifiers should only be
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#26 pre amp

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#2,384
massimo said:
Just to show Merlin (as promised) what can be done with a pair of Galaxy Maggiorato enclosures.
On the top of the PS unit, pw xfrm and choke, inside two 15V/50VA xfrms for Coleman's regs. Between the xfrms 8 diodes on a yet-to-be-made pcb. Several caps (big elcaps for filaments, pp for HV) will take space inside too.
The pream hosts two Tango 160H chokes and inside the filament bias Dale's fixing hardware is contact with the front panel through an alu bar. The other two L shaped alu bars are hosting the Coleman's regs and the SSHV2 (pcbs yet-to-be-made) spreading heat on the sides and the top cover. Close to the SSHV2 regs another pcb with 10 pcs 10uF pp caps
A suspended copper subchassis will host the tube sockets.
Click to expand...

Very good Massimo, I am a fan of copper, and I like the idea for the sockets, keep us posted on the evolution.
 
#2,388
mogliaa said:
Great work Felipe, looking really good!
As a suggestion, you may want to consider increasing the space between individual resistors of each stack as they will get hot. Not the most efficient way to dissipate the heat by stacking them up vertically. I have them just like you buy added some metal separators between them an longer screws...
Ale
Click to expand...

It's enough the increased space between individual resistor?
 

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#2,394
That's better Filipe. Looks good to me.

I've gone back to my 26 preamp with the two 156C in series and updated the power supply a bit. The hum is still there but not audible from my listening seat, just close up to the speaker. So that's proof to me that the 156C option is viable. I must say it sounds really nice with the FT-2 teflon output caps. I'm using a couple of ordinary commercial 12v DC supplies - probably switch mode I'd guess though I haven't got inside them. They sound much better than I'd expect!
 

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#2,396
andyjevans said:
That's better Filipe. Looks good to me.

I've gone back to my 26 preamp with the two 156C in series and updated the power supply a bit. The hum is still there but not audible from my listening seat, just close up to the speaker. So that's proof to me that the 156C option is viable. I must say it sounds really nice with the FT-2 teflon output caps. I'm using a couple of ordinary commercial 12v DC supplies - probably switch mode I'd guess though I haven't got inside them. They sound much better than I'd expect!
Click to expand...

Thanks Andy,

Try FT-3 in place of FT-2, huge difference: I have both.

Cheers, Felipe
 
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