Hi Terry, congratulations! Your pace is incredible. Thank you for testing. Once again, great support and preparatory work for everyone who wants to build a new amplifier.
regards Olaf
regards Olaf
Nice work Terry. So how does this compare with FH11/12 that you made earlier?
I like this one better. It is dead quiet and no turn-on thump. No hot transistors. Sound as good. It reminds me more of the FX100 than anything else. If you uild it make sure you have plenty 1N4148's. It used 10 per channel. 😉
If you uild it make sure you have plenty 1N4148's. It used 10 per channel. 😉
Fortunately, they're cheap.
Fortunately, they're cheap.
Agreed. Just saying have plenty on hand. I played the amp pretty loud for about a half hour. Kind of a smallish heatsink for this much amp but thermal compensation does its job. I have the bias set to 90mA. After the half hour of loud playing it settles at 86mA. Just about perfect I think. I'm playing it at +-59V rails. Didn't try 4 ohms but just breezes along on 8 ohm. I also checked the MJE340/350 and they are a little warm. I can keep my finger on them but it might not hurt to have a small sink on them. Still liking the sound a lot.
Hello Terry
greetings as usual very nice build can you post PDF iron transfer pcb bottom
side if its possible
warm regards
Andrew
greetings as usual very nice build can you post PDF iron transfer pcb bottom
side if its possible
warm regards
Andrew
Nice work Terry!
Do you ever tire of building?
🙂
mlloyd1
Do you ever tire of building?
🙂
mlloyd1
Sorry, I took the day off yesterday. I fired it up today. Nice! ....
Blessings, Terry
Hey Andrew,
I'm attaching the iron transfer files I used.
could you please post sprint6 lay document as well, if you have it? I have sr150 bjt version, this one I would like to have too and I really like the way this pcb was done. great job!
Nice work Terry!
Do you ever tire of building?
🙂
mlloyd1
I have slowed down. I have an obscene amount of amps now. It is hard to resist the simple ones that are suitable for etching. Mile's amps almost always work and are good sounding. Nirvana for the DIY enthusiast.
could you please post sprint6 lay document as well, if you have it? I have sr150 bjt version, this one I would like to have too and I really like the way this pcb was done. great job!
Sure. It is actually Kuntarman's layout. I just revised it a little so I could use parts I had and I wanted to add a couple caps to the rail.
Attachments
Sorry, I took the day off yesterday. I fired it up today. Nice! I hfe matched the small transistors and I have 2mV offset one channel and 3mV on the other. I used a 2k trimmer and it very ample for adjusting the bias. I have it set to 90mA. Square waves are very clean. Just a slight rounding of the leading edge at 20khz. 100hz is almost flat and the bass response reveals this. Bass is deep and tight. Really sounds great and is very stable. Kuntarman's layout is good except for the LED needing to be inverted.
Another winner from APEX.
Blessings, Terry
Nice work, this will be my favorite hexfet amplifier.
Regards
Nice work, this will be my favorite hexfet amplifier.
Regards
Great topology Mile

Very much in line with what I'm up to these days. "Current drive" front-end 😎
Sure. It is actually Kuntarman's layout. I just revised it a little so I could use parts I had and I wanted to add a couple caps to the rail.
Hi Terry,
I tried opening this file but my computer says it's an invalid zip file. Is this the Gerber package? Could you kindly please re-post the Gerber for the FR100?
Thanks,
X
Weird. When I zipped it I chose zip not rar. That was not the gerber file it was a .lay file or Sprint 6. I can try to export gerbers. Give me a few minutes.
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