The tubes come out the back like a Marantz 7.
You can leave it on for a week and still not get hot enough to burn yourself on. I used preamp tubes in my preamp, 11.5 volts dc on a 12v filament so it runs cool as a cucumber. I'm not the best at uploading photos sorry.
You can leave it on for a week and still not get hot enough to burn yourself on. I used preamp tubes in my preamp, 11.5 volts dc on a 12v filament so it runs cool as a cucumber. I'm not the best at uploading photos sorry.
Last edited:
@midnightmayhem, isn't running tube too cool bad for them? anyhow if they are on the back like on the Marantz it should indeed be no problem at all
Running tubes too cool is bad for me!
Music ceases to be amplified.
The filament voltage being run 1v low is standard best practices for obtaining lowest noise. Good tubes will last decades in my preamp. A full set of good tubes can be had for under $100. I have plenty of both types stashed, so I can't bring myself to loose sleep over it.
Actually the damn thing is so quiet I regularly fall asleep and leave it on all night...
Finished a GU-72 SET monoblock, which will likely stay mono
560V / 150mA operating point, fixed bias
C3m driver RC coupled
OPT (5K) from SAC Thailand
CLCRC PSU
No feedback, all very simple
560V / 150mA operating point, fixed bias
C3m driver RC coupled
OPT (5K) from SAC Thailand
CLCRC PSU
No feedback, all very simple
Attachments
Finished a GU-72 SET monoblock, which will likely stay mono
560V / 150mA operating point, fixed bias
C3m driver RC coupled
OPT (5K) from SAC Thailand
CLCRC PSU
No feedback, all very simple
"All very simple ...." Got tubes, transformers, chassis, but no inspiration; could you please share the schematic?
Great to see someone using these tubes. Guess you have some 20-25W to fiddle with?!
Nice work there, well done. What's that software your using to measure harmonics? Arta?
Andy.
It's REW, free, simple, nice
Here, drew it. The bias regulator is by Pete Millett as on his website"All very simple ...." Got tubes, transformers, chassis, but no inspiration; could you please share the schematic?
Great to see someone using these tubes. Guess you have some 20-25W to fiddle with?!
In my set up it is 15W, but can be upped to 20-25W if needed, sure
As to build advice - simple solid core wire works well enough for the anode cap. I tried to make something fancy from copper bar, did not succeed much
Attachments
Thanks a lot! I will look into this. As it is a tetrode it is definitely easier to handle as triodes I guess.
I have a transformer that will give me a B+ of 700V.
I have a transformer that will give me a B+ of 700V.
I have been into deep thoughts myself about a cool anode cap, but then again ... "it's just only 700V on the anode plate .... "I tried to make something fancy from copper bar, did not succeed much
I've not tried REW for a while, I had trouble calibrating my AI,couldn't get it right. Had more success with ARTA and the easiest scope/sig gen/THD/FFT is Soundcard Scope.It's REW, free, simple, nice
Grand fettling there Dr, I have some 6BG6's on order at present.
Like the way you terminated the top cap wiring, I do that too, especially with screened grid caps.
Andy.
Here is a Bottlehead crack I picked up used and fixed up a bit. Electrically all I needed to do was redo some suspect heater wiring and I switched it to take 6CG7 while I was at it, other than that it is stock. The sound with my AKG sextett phones was so pretty I decided it needed a sexier look. I made the new base from curly maple with a thin black inlay and changed the proportions to be a little less clunky. I hand rubbed a finish with tung oil and wax. I made a vented bottom plate from some aluminum perf metal, secured the top plate to the base, painted the end bell and added a vintage knob. Not a fan of tube rolling so I just picked tubes from my stash to work the best in their positions. I.E. the highest transconductance 6080 I had with matched sections.
Attachments
- Home
- Amplifiers
- Tubes / Valves
- Photo Gallery