Single-Ended Pentode Redux

What people are working on at the moment
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Paul Barker
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#76 Re: Single-Ended Pentode Redux

Post by Paul Barker »

cool!
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#77 Re: Single-Ended Pentode Redux

Post by Cressy Snr »

Been fecking with the power supply this afternoon and have split the channels after the CLC filter.

Now it’s 50u/4H/50u then splitting into one 220R/100u RC filter per channel.
Can’t listen properly yet: not until after “The Masked Singer” finishes :shock: :lol:
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#78 Re: Single-Ended Pentode Redux

Post by Ant »

Good god you do watch some shite
Also starring Rex Hamilton as Abraham Lincoln

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#79 Re: Single-Ended Pentode Redux

Post by Cressy Snr »

It’s not me, It’s your mam. :lol:
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#80 Re: Single-Ended Pentode Redux

Post by Paul Barker »

lol
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#81 Re: Single-Ended Pentode Redux

Post by Cressy Snr »

Been doing a bit of planning for the next iteration of the E-Linear amplifier. Driver stage will be a D3a in pentode mode:
Elinearpentdriver.png
Elinearpentdriver.png (44.13 KiB) Viewed 1746 times
This will be the one that will go in the box if it works as well as I think it will.
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#82 Re: Single-Ended Pentode Redux

Post by Cressy Snr »

Tried this PSU on the existing 6V6 iteration:
Elinsplitchokespsu.png
Elinsplitchokespsu.png (65.25 KiB) Viewed 1721 times
It's nice.
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#83 Re: Single-Ended Pentode Redux

Post by Cressy Snr »

Again, I can ‘sense’ the silence, but this time there is no sonic penalty.
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#84 Re: Single-Ended Pentode Redux

Post by steve s »

Cressy Snr wrote: Tue Jan 25, 2022 8:00 pm Tried this PSU on the existing 6V6 iteration:
Elinsplitchokespsu.png
It's nice.
Thats close to the layout on my mofo drivers Steve, but like to run closer to choke input, and then adjust the 1st cap to get the voltage where I want it, usually .5 to 4 uf, but again that is very transformer dependant (what I have vs the voltages I want)
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#85 Re: Single-Ended Pentode Redux

Post by Paul Barker »

steve s wrote: Wed Jan 26, 2022 9:00 am
Cressy Snr wrote: Tue Jan 25, 2022 8:00 pm Tried this PSU on the existing 6V6 iteration:
Elinsplitchokespsu.png
It's nice.
Thats close to the layout on my mofo drivers Steve, but like to run closer to choke input, and then adjust the 1st cap to get the voltage where I want it, usually .5 to 4 uf, but again that is very transformer dependant (what I have vs the voltages I want)
It always goes like that.
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#86 Re: Single-Ended Pentode Redux

Post by steve s »

Paul Barker wrote: Wed Jan 26, 2022 9:14 am
It always goes like that.
True I've been lucky enough to buy all the decent looking transformers I can from radio rally's this last 20 odd years, all have been great.. but I ways listen for crackles in the dark now.

The other things I always do is measure the resistances of both windings, usually about 1or 2 ohm difference I then add resistance to match them up. I also make sure the rectifier is matched both sides, and add a small cap across the 1st choke.

All things I read about in 1930s books

Wouldn't like to say they make a difference.

The skill is linking what you hear and recognition of whats doing what.
Dynamics and bass response are the thing to focus on. But there's loads of other parts of the amp, (or should I say all) affect these too
I would guess dynamics are hard to measure but I trust my ears, rightly or wrongly
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#87 Re: Single-Ended Pentode Redux

Post by Cressy Snr »

steve s wrote: Wed Jan 26, 2022 9:00 am... I like to run closer to choke input, and then adjust the 1st cap to get the voltage where I want it...
I've done this now with the PSU for the E-Linear amp:
Elinsplitchokecheatcap.png
Elinsplitchokecheatcap.png (66.74 KiB) Viewed 1613 times
It's putting out the voltages bang where I want them - 5R4GY being used to cater for 6V6 and GZ34 to cater for EL34.

6V6 is running at about 80% of plate dissipation.
EL34 runs at around 50%.
Both valves sound great.

Edit the quote from Steve was fooked up.
Last edited by Cressy Snr on Wed Jan 26, 2022 7:21 pm, edited 1 time in total.
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#88 Re: Single-Ended Pentode Redux

Post by Cressy Snr »

PSUD sim:
Screenshot 2022-01-26 at 16.51.48.png
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#89 Re: Single-Ended Pentode Redux

Post by Nick »

The problem now is the Dcr of the second choke. But then you end up with boatankers.
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#90 Re: Single-Ended Pentode Redux

Post by Cressy Snr »

Nick wrote: Wed Jan 26, 2022 4:55 pm The problem now is the Dcr of the second choke. But then you end up with boatankers.
Aye, that was in my mind all the time, but they’re all I have. TBH I’m now at the limit as to what I can achieve passively with the parts I have. It’s obviously crying out for a regulator as the next point in its evolution.
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