Miles
You just had to tease me with a 807 amplifier. I have been gathering parts for one and now after seeing yours I will have to make one.
I'll bet it sounds sweet.
You just had to tease me with a 807 amplifier. I have been gathering parts for one and now after seeing yours I will have to make one.
I'll bet it sounds sweet.
burnedfingers said:
Yuppers, sounded very fine even before connecting the NFB, and it doesn't require very much of that. Even though 807s are officially an "xmtr" VT, they are outstanding performers for audio as well.
"I will have to make one." Hop to it! 😀
My latest effort, crafted from specially selected alloys chosen after hundreds of hours of listening tests. The precision machining took over 1,000 hours and was done by specially trained craftsmen. No expense was spared in the selection and qualification of components. This is truly what high end audio is all about.
Attachments
SY said:
Ah, your LED-cathode-bias EL84 amp? Hmmm, I'm gonna do the same thing but hide the LED's inside 🙂
SY,
The faux rust work is EXCELLENT... as are your efforts to get that antique patina... very nice
Do explain the LEDS, a CCS with 32 stage cascode, fast bass, or what?
😀
The faux rust work is EXCELLENT... as are your efforts to get that antique patina... very nice
Do explain the LEDS, a CCS with 32 stage cascode, fast bass, or what?
😀
Aren't they supposed to be red and green for right and left channel?
EDIT: the boaters among us will understand 😉
EDIT: the boaters among us will understand 😉
All joking aside, the LEDs actually were quite carefully chosen. Low dynamic impedance is tough to find these days.
And I should credit pinkmouse for cleaning up my photo.
And I should credit pinkmouse for cleaning up my photo.
SY said:
What do figure the dynamic impedance is at the current being run? A couple of nights ago I assembled a jig to test AC impedance of LEDs biased by a variable CCS and driven with a sound card. A rough calc suggests the lowest AC impedance LED in the junk box is about 7 ohms at 1000 Hz with 15 ma static DC bias. Are significantly lower to be had? BTW, thanks for the tip on LED biasing, much cheaper than Mills wirewound.
The LEDs I use have an AC impedance of 4.5 ohms. Cheaper than a Mills, and no need for bypassing- gets that whomping electrolytic out of there. But I had to try at least a dozen varieties until I hit one this good.
7 ohms sounds like one of the better "super bright" red.
7 ohms sounds like one of the better "super bright" red.
That's an accurate description of its appearance, small and bright. Unfortunately that's also the only information on them. I buy them in bags-o-LED packaging from the local jobber. Currently using one as cathode load for an Ultrapath 6c45 and it works very, very well.
And this is my next construction. This is a tube amp witch I use when I need quietly play in my home (noice witch made this amp no irritate neighbours 🙂. The amp have a clean chanel like a Fender amp. In the first stage I use the ECC83. The next stage include EL84 witch create 4W power. The box this is a wine package.
Attachments
My 12B4 preamp.
I salvaged an old data switch for parallel printers and built the 12B4 preamp into it.
Here's the front
and he back
I salvaged an old data switch for parallel printers and built the 12B4 preamp into it.
Here's the front
An externally hosted image should be here but it was not working when we last tested it.
and he back
An externally hosted image should be here but it was not working when we last tested it.
