My take on a heater supply...

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IslandPink
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#46 Re: My take on a heater supply...

Post by IslandPink »

ed wrote: Tue Apr 18, 2017 2:59 pm
I must have been away when all this occurred but I would ask the same question as Simon at first. I too had no visibility of the top octave not working......so, two questions
1. are the Mark/Andrew solutions readily available and can they cope with high currents, and
2. How does this all compare with Guido's solution?

yes, I know, that makes three questions really
Andrew knows more about where we are with the higher-current (3A?) ones, but I've used one for a decent period to test GK-71 ( ie. same as GM70 ) so 3A and 20V - sounded really good ( better than KR300B with Guido's ) . Now, this was fed from a 24V 5A Sony laptop SMPS - just didn't fit the rectifiers or smoothing caps to the board & patched in the 23.8V to feed the voltage reg & current-reg. I think however Nick and Andrew had more developments in the pipeline for higher current. Maybe other Nick can comment too and my apologies for using his thread to continue a bit off-topic.
I did most of my testing with a 4P1L driver valve for 300B, and the Guido ones were on the output stage 300B. So.... I think Andrew's ones are better than Guidos ( but bear in mind these are the original Guido type so about 13 or more years old ) but this is based on KR300B+Guido vs. GK71 triode+Lehane ; both with Bud Purvine output trannies.
We know the Lehane ones match Rod Colemans in the bass and mids, and improve on them in the treble. Also they beat Thorsten's DIY ones with coils, caps and CMC, that he used on the 'Ladyday' mods - had those to hand during testing.
It's worth saying that AC heating and the Thorsten ones ( passive, low output impedance ) both beat the Coleman ones in treble, so you can understand why there are lengthy debates on DHT threads about DC vs. AC. It's all about implementation with DC DHT heating.

( also worth mentioning Rod's ones have gone up one more version now - v5? - but I don't know what the changes are )
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ed
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#47 Re: My take on a heater supply...

Post by ed »

thanks Mark

I read from this that they weren't aimed at 4 amps and above, so maybe not what we're looking for with sv572.
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#48 Re: My take on a heater supply...

Post by Andrew »

jack wrote: Sat Apr 15, 2017 8:04 pm
A postfix linear regulator (or buck-boost pre-regulation) neatly addresses most of these compromises, but it's very hard to get the balance right...
Hi Nick,

I'm a bit unsure of what you mean here by postfix and pre-reg, could you elaborate, please? I think I have a picture in my head of what you're proposing - some combination of a two stage reg. A block diagram perhaps?

thanks,

Andrew
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simon
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#49 Re: My take on a heater supply...

Post by simon »

IslandPink wrote: ( also worth mentioning Rod's ones have gone up one more version now - v5? - but I don't know what the changes are )
I think Rod's are v7 now. I think there's supposed to be a nice improvement over v4. Mine are v2 so I'm way behind.
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#50 Re: My take on a heater supply...

Post by jack »

I'm slightly off-grid at the moment - been in Abu Dhabi yesterday, the desert in Sharjah today dune bashing for my birthday, off to Oman tomorrow for 10 days...

No block diagram as travelling, but three key stages: ideal rectifier, SMPS pre-regulator, final ultra-low-noise linear regulator. Programmable slow-start and shutdown, opto-isolated enable input and power good out (for daisy​-chaining).

Currently looking at one-size-fits-all to simplify design and production. Probably 8A, 5 to 20V out. Current limited and short circuit proof. High dynamic range - 6 octaves. Also possible option of HV B+ variant.

One of the driving reasons for doing this is my large cache of 13E1s and 6C33C-Bs.
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#51 Re: My take on a heater supply...

Post by Mike H »

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#52 Re: My take on a heater supply...

Post by Andrew »

jack wrote: Wed Apr 19, 2017 7:57 pm
No block diagram as travelling, but three key stages: ideal rectifier, SMPS pre-regulator, final ultra-low-noise linear regulator. Programmable slow-start and shutdown, opto-isolated enable input and power good out (for daisy​-chaining).
That makes a lot of sense as a block diagram, thanks. Opto isolated good in/out control is a nice touch.

Andrew
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