Thanks Bfpca,
What power transformer did you use to get the 3 options?
I made a start last night on this. Decided to mount a 250v 6amp toggle switch into the bottom plate towards the back. My amps are up on spikes to allow plenty of air flow so if I want to change the setting I can just power things down, wait a few minutes for discharge and slip my hand safely under each amp and change the B+. bonus is they are out of sight for anyone else.
Will post a couple of pics when finished.
Cheers
What power transformer did you use to get the 3 options?
Absolutely agree.
I made a start last night on this. Decided to mount a 250v 6amp toggle switch into the bottom plate towards the back. My amps are up on spikes to allow plenty of air flow so if I want to change the setting I can just power things down, wait a few minutes for discharge and slip my hand safely under each amp and change the B+. bonus is they are out of sight for anyone else.
Will post a couple of pics when finished.
Cheers
What power transformer did I use for adjustable B+?
My apologies! I forgot to mention that I am using a regulated B+. So I am merely adjusting the regulated supply output.
I have been using my SS First Watt F5 V3 monoblocks all year but I want to revisit the BH EL34 as soon as I finish my current tube pre amp build.
I need to make some more tweaks to the circuitry and finish a couple of trim pieces on the chassis. I found that I liked the EL84 version better, which means I have some work to do to optimize the EL34.
Looking forward to pics!
My apologies! I forgot to mention that I am using a regulated B+. So I am merely adjusting the regulated supply output.
I have been using my SS First Watt F5 V3 monoblocks all year but I want to revisit the BH EL34 as soon as I finish my current tube pre amp build.
I need to make some more tweaks to the circuitry and finish a couple of trim pieces on the chassis. I found that I liked the EL84 version better, which means I have some work to do to optimize the EL34.
Looking forward to pics!
Thanks for your feedback Bfpca, I remember you suggested me the F5 as your favourite amp and I'm tempted to build one indeed.
Concerning the BH EL84 vs EL34 (with all possible tubes), here the 12AX7 character comes out way more because of the increased needed swing, and this is something I don't like too much.
With a B+ of 450V it can be partially improved with a 270k plate resistor on 12AX7 instead of the standard 220k and adjusting the value of the CCS, being then able to swing around 150Vpp with 2Vrms input. This gives some "room" to apply feedback a thame 12AX7's character.
As I was reporting in another thread, this is where French very smartly applied ODNF (only distortion negative feedback, or correction différentielle as they call it), so the other side of the phase splitter will see only the distortion and not the full signal from the output.
Concerning the BH EL84 vs EL34 (with all possible tubes), here the 12AX7 character comes out way more because of the increased needed swing, and this is something I don't like too much.
With a B+ of 450V it can be partially improved with a 270k plate resistor on 12AX7 instead of the standard 220k and adjusting the value of the CCS, being then able to swing around 150Vpp with 2Vrms input. This gives some "room" to apply feedback a thame 12AX7's character.
As I was reporting in another thread, this is where French very smartly applied ODNF (only distortion negative feedback, or correction différentielle as they call it), so the other side of the phase splitter will see only the distortion and not the full signal from the output.
I got the chassis back from the paint shop on Friday. It was inexpensive and quick. The finish is a bit rougher than expected, but that's probably because this particular paint shop mainly deals with industrial stuff and machinery. Their main concern is corrosion protection and not so much about looks. I didn't think about that when I gave them the job. Still, it looks quite good.
Today I reinstalled all the parts, and took time to make the wiring tidy. Retested everything again, and it still seems to work (no smoke ...). Will hopefully listen to some music tomorrow.
Today I reinstalled all the parts, and took time to make the wiring tidy. Retested everything again, and it still seems to work (no smoke ...). Will hopefully listen to some music tomorrow.
Attachments
Yes, they are fast! I was told they do black every other day. Apparently their most popular colour.
Listened to music all day (which is one of the advantages of working from home), and I'm very pleased with my new amplifier. Listened to jazz mostly (Bill Evans, John Handy, Coltrane) and rounded of with The Doors. It handled everything well to my ears.
Perhaps (probably) confirmation bias, but I think it sounds more lively and engaging than my M2X.
At the end of the workday I noticed a intermittent hissing sound from the right channel, and I narrowed it down to one of the 6n2p tubes. Replaced it, and everything good. I wonder if quality control on the Soviet tubes was a bit sketchy?
Perhaps (probably) confirmation bias, but I think it sounds more lively and engaging than my M2X.
At the end of the workday I noticed a intermittent hissing sound from the right channel, and I narrowed it down to one of the 6n2p tubes. Replaced it, and everything good. I wonder if quality control on the Soviet tubes was a bit sketchy?
Hey tbaashus
Great feeling of self satisfaction and beautiful music, nice one!
Have a read here
Any good 6N2 out there? | Audiokarma Home Audio Stereo Discussion Forums
I just had 2 x 6N2P-EV tubes delivered from a very reputable seller here in NZ, Im not able to test them in an amp until I complete the next BH build. I will also try to test on my TV7 if I can find the test data.
Great feeling of self satisfaction and beautiful music, nice one!
Have a read here
Any good 6N2 out there? | Audiokarma Home Audio Stereo Discussion Forums
I just had 2 x 6N2P-EV tubes delivered from a very reputable seller here in NZ, Im not able to test them in an amp until I complete the next BH build. I will also try to test on my TV7 if I can find the test data.
Interesting reading. I have some faint hiss if both channels, which isn't noticable from a listening position. Will compare with ECC83.
They were bought directly from Ukraine, but it's been a long while since a bought them.
Consider that if you don't have used them, you can always ask. Worst case is that they say no. But they could also invest in your case as marketing: an happy customer can promote more than simple marketing.
I wonder whether a lot of seconds circulate: NOS tubes, quality not in the top decile, but perfectly adequate for specific purposes and delivered in bulk to be used as spares.
Also, how many people have seen a NOS tube advertised, in opened boxes, but not actually contemporary or even the same brand? I.e. the pulls kept in past times as spares, or never disposed of.
In the old days tube selection was required to get the best performance, with 10 or 20 tubes being bought to find a quad. A good example being EF12s used for microphones. I think we are over-estimating the tolerances that were acceptable for what are essentially consumer items.
Also, how many people have seen a NOS tube advertised, in opened boxes, but not actually contemporary or even the same brand? I.e. the pulls kept in past times as spares, or never disposed of.
In the old days tube selection was required to get the best performance, with 10 or 20 tubes being bought to find a quad. A good example being EF12s used for microphones. I think we are over-estimating the tolerances that were acceptable for what are essentially consumer items.
