Poundland 45

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RhythMick
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#61 Re: Poundland 45

Post by RhythMick »

I have a good handful of BG caps I will never use if you want them Steve.

Several are doubles (220+220, 50+50, 100+100 maybe) and a few singles.
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Nick
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#62 Re: Poundland 45

Post by Nick »

where it might be better employed
Regulators.
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#63 Re: Poundland 45

Post by Cressy Snr »

@Rhythmick.
Thanks Mick I'll keep that in mind. :)

@Nick
Yes, I intend to regulate and the BG cap will come in very handy.
In the first instance, the supply will be unregulated: a similar sort of thing to the one Mark uses on his phono.
I have a couple of the MJ statistical regs, but I'd have to add some more zeners to the string to get the voltage where I want it.
The good thing with the phono is that I have the chassis from an ancient VCR in which to put all the power supply bits, which means that for the first time in ages, I have a box that is plenty big enough for whatever I decide to put in there.
The audio circuit will of course go in another box entirely.
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Nick
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#64 Re: Poundland 45

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Yes, I intend to regulate and the BG cap will come in very handy.
How? I would have thought a film cap after the regulator would be good if the HF is a bit untidy, But there should be no reason to need a BG unless its a poor regulator, and there is no point using it before the regulator. And remember the small resistor and cap after the regulator if the regulator is audible.
I have a couple of the MJ statistical regs
I would have suggested you meed something with more current capacity. I thought the stat reg was aimed at things like g2 supply of low current pentodes.
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#65 Re: Poundland 45

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Just ignore me Nick. I’ve gone completely fecking wappy.
I’ll be back when I’ve got something vaguely sensible to contribute.
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IslandPink
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#66 Re: Poundland 45

Post by IslandPink »

Cressy Snr wrote: Mon Sep 06, 2021 2:53 pm In the first instance, the supply will be unregulated: a similar sort of thing to the one Mark uses on his phono.
Erm.... you mean my shunt-regulated phono supply ? :)
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#67 Re: Poundland 45

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IslandPink wrote: Mon Sep 06, 2021 8:00 pm
Cressy Snr wrote: Mon Sep 06, 2021 2:53 pm In the first instance, the supply will be unregulated: a similar sort of thing to the one Mark uses on his phono.
Erm.... you mean my shunt-regulated phono supply ? :)
It's the heat, Steve. We're not used to it !
Yes that’s it. Beats me what I was bleed’n talking about after that. :lol:
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izzy wizzy
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#68 Re: Poundland 45

Post by izzy wizzy »

BTW, I tried hearing the difference between a good BHC electro and a BG WKz before a resistor/gas shunt reg in my line stage and I really couldn't tell the difference. It is differential which would reduce the difference but still. And I'm a fan of the WKz and have them throughout my phono (no regulators, only LC). A CCS/shunt would minimise that even further probably.
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#69 Re: Poundland 45

Post by Cressy Snr »

So yesterday I did a resistor/glow tube stack shunt reg feed to the input stage and was pleased with the results.
Today I decided it was time to take a leaf out of Mark's phono stage book and feed the glow tube stack from a constant current source. 'Sod it! Just do it!' I thought.

I've got a load of DN2540G5 depletion mode MOSFETs, so employed a cascode pair in a simple lift from Morgan Jones book.
An improvement in bass definition/transient attack speed and decay time, is very noticeable.

I regulated the whole HT on my 6B4G mono blocks using a 6080 series reg, but I hadn't really got to grips with the need to decouple the input and output stages from each other, so it was very good, but could have been even better.
This little scheme on the 45 amp, regulating just the input stage, gives a very nice sonic experience.
Screenshot 2021-09-07 at 19.42.01.png
Screenshot 2021-09-07 at 19.42.01.png (83.41 KiB) Viewed 2911 times
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izzy wizzy
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#70 Re: Poundland 45

Post by izzy wizzy »

Rinse and repeat for phono. PSU done ;)
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#71 Re: Poundland 45

Post by IslandPink »

Cool !
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andrew Ivimey
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#72 Re: Poundland 45

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Cool rinse doesn't get the soap out!
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RhythMick
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#73 Re: Poundland 45

Post by RhythMick »

Cressy Snr wrote: Tue Sep 07, 2021 8:03 pm So yesterday I did a resistor/glow tube stack shunt reg feed to the input stage and was pleased with the results.
Today I decided it was time to take a leaf out of Mark's phono stage book and feed the glow tube stack from a constant current source. 'Sod it! Just do it!' I thought.

I've got a load of DN2540G5 depletion mode MOSFETs, so employed a cascode pair in a simple lift from Morgan Jones book.
An improvement in bass definition/transient attack speed and decay time, is very noticeable.

I regulated the whole HT on my 6B4G mono blocks using a 6080 series reg, but I hadn't really got to grips with the need to decouple the input and output stages from each other, so it was very good, but could have been even better.
This little scheme on the 45 amp, regulating just the input stage, gives a very nice sonic experience.

Screenshot 2021-09-07 at 19.42.01.png
Nice work Steve and similar to what I'm planning with the phono.

Side question - what software are you using to produce the circuit diagrams ?
RhythMick
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#74 Re: Poundland 45

Post by RhythMick »

Cressy Snr wrote: Tue Sep 07, 2021 8:03 pm So yesterday I did a resistor/glow tube stack shunt reg feed to the input stage and was pleased with the results.
Today I decided it was time to take a leaf out of Mark's phono stage book and feed the glow tube stack from a constant current source. 'Sod it! Just do it!' I thought.

I've got a load of DN2540G5 depletion mode MOSFETs, so employed a cascode pair in a simple lift from Morgan Jones book.
An improvement in bass definition/transient attack speed and decay time, is very noticeable.

I regulated the whole HT on my 6B4G mono blocks using a 6080 series reg, but I hadn't really got to grips with the need to decouple the input and output stages from each other, so it was very good, but could have been even better.
This little scheme on the 45 amp, regulating just the input stage, gives a very nice sonic experience.

Screenshot 2021-09-07 at 19.42.01.png
Question ? Would it be better to put the glow tube stack before the CCS ? I'd heard they are noisy (?) and if so maybe better to isolate the valve from them via the DN2540s ?
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Nick
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#75 Re: Poundland 45

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Question ? Would it be better to put the glow tube stack before the CCS ? I'd heard they are noisy (?) and if so maybe better to isolate the valve from them via the DN2540s
Simple answer no.

Longer version, what would you think would happen? Its a CCS so what is it isolating and why, and what happens if the load is drawing more or less current (or a varying current as will actually happen) than the CCS is set to pass? The CCS controls the total current, the shunt tube passes the excess current that the load is not using and does so while maintaining a generally constant voltage across the load. The cap across the glow tube gets rid of some noise, a zobel is possibly better. If you want less noise then a SS regulator would be the solution, but sometimes good enough is good enough and VR tubes tend to sound nice and are a simple and effective way of providing a shunt regulator. Marks shunt is better in all ways other than simplicity. Noise is not the only measure of how good a regulator is, response to load changes can also be very important but harder to measure so often ignored.
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