I am using 2 6D22S half wave rectifiers for my 850v B+ in my GM70 amp and they take a while to warm up and produce full power. Here is a blurb from the sales sheet.
"The 6D22S features very slow warmup (30 seconds
typical), making it an excellent, rugged power-on delay device for audio amplifiers.
Its warm-up time is longer than that of common rectifier tubes (such as the 5AR4/
GZ34), and it is lower in cost than electronic delay relays."
"The 6D22S features very slow warmup (30 seconds
typical), making it an excellent, rugged power-on delay device for audio amplifiers.
Its warm-up time is longer than that of common rectifier tubes (such as the 5AR4/
GZ34), and it is lower in cost than electronic delay relays."
Hi Rod,
Thanks a lot for sharing the circuit. I'll try it in my next amp 😉
Or.... I see it as a voltage source, so I can adjust the polarity of some parts and insert it to the position of cathode resistor, no?
😀
[edit] Ah, no. Bias voltage and B+ are stacked, and I don't have that much voltage to spare in this amp. Another bias supply is still needed. 🙁
Hi djn,
I've tested Sovtec 5AR4 and Mullard GZ37, they both take about 30 sec. to warm up. Very similar (if not identical) behavior as the TV damper diodes I'm currently using (6AU4 and 6W4).
I'd agree with cost thingy, though.
Thanks a lot for sharing the circuit. I'll try it in my next amp 😉
Or.... I see it as a voltage source, so I can adjust the polarity of some parts and insert it to the position of cathode resistor, no?
😀
[edit] Ah, no. Bias voltage and B+ are stacked, and I don't have that much voltage to spare in this amp. Another bias supply is still needed. 🙁
Hi djn,
I've tested Sovtec 5AR4 and Mullard GZ37, they both take about 30 sec. to warm up. Very similar (if not identical) behavior as the TV damper diodes I'm currently using (6AU4 and 6W4).
I'd agree with cost thingy, though.
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Hi Rod,
Please, add 4 boards for my GM70s and if possible a 7V 5A or similar for my field coil drivers.
Thanks
Josep
Please, add 4 boards for my GM70s and if possible a 7V 5A or similar for my field coil drivers.
Thanks
Josep
Rod, I'll be looking for 2x #26 (1.05A,1.5V) and 4x 71A (.25A 5V) boards. You will let us know when to signup& pay ?
Hey Rod,
Haven´t followed this thread for a long time.
Will the cards work for 1,5V/200mA?
Are they assembled or just PCBs?
Price?
Might need two pairs anyway.
Haven´t followed this thread for a long time.
Will the cards work for 1,5V/200mA?
Are they assembled or just PCBs?
Price?
Might need two pairs anyway.
Hi Rod! if you do not quickly make me a kit for heart burn tube 26, then I will have the right PCB copy of which you now! hi, hi
Dave, message sent, with design notes.
After a long testing period, the regulators are available! There has been a long round of qualification to be sure the regulators are reliable. I have built all the different varieties listed, so that the kits can be built to give a nominal current, with adjustment on either side [trimmer pot]. I built all the power supplies too, so that I can recommend the trafo ratings and cap sizes. It's all in the application notes.
The regulators normally come as a kit for self-assembly, but for a little extra cost they can be assembled & tested. You just add a transformer, rectifier, and capacitors, and choose a heatsink (guide given).
Initial models:
LP2, P2, B406, 215P, DC70, 3A5, 01A, 71A, 112A, 4021, 3A/109B, LS8A, #26, 6B4G, 6A3, #56, ML4, MHL4, PX4, WE102D, 801A, 10Y, 210T, #50, 300B, 45, 46, 27, 1624 [beam tube] 2A3.
Transmitting tubes: 805, 845 3C24 etc.
The GM70 needs another brief round of work, but will certainly be available. I just need to be sure it withstands the big turn-ON thermal pulse under all situations. After that, I'll look at the 75TL, 100TL.
There's a dozen or so pairs of boards that aren't reserved yet - but I'll be getting some more made, by the look of it!
To have the application notes [PDF], and buying details, please send me some PM.
.
Hey Rod,
Just wanted to let you know I have had some serious computer issues over the past few weeks and was not able to review the documentation fully for the boards - what I did see seemed pretty comprehensive. I'm hoping to have a new desktop together in a week or so and should be able to access all of my old emails shortly thereafter.
Sorry for the silence.. So much catching up to do.. 😀
Just wanted to let you know I have had some serious computer issues over the past few weeks and was not able to review the documentation fully for the boards - what I did see seemed pretty comprehensive. I'm hoping to have a new desktop together in a week or so and should be able to access all of my old emails shortly thereafter.
Sorry for the silence.. So much catching up to do.. 😀
Hi Rod, I will have your manual (application notes) done this weekend. It is looking very nice. Hopefully, you can email the manual to the buyers as it grew a bit in size just for readability. Cheers. Dennis.
Thanks Dennis! I'll be looking out for them.
Kevin, please look out for some much revised documentation soon! I have quite a few more paragraphs to add, too!
Kevin, please look out for some much revised documentation soon! I have quite a few more paragraphs to add, too!
Hi Rod, I just emailed it to you. Something came up for this weekend and I figured I'd knock it out now. Let me know.
Hi Rod
As I am building a 26 preamp, your PCB/Kit is of great interest to me. Please let me know if/when you have some for sale.
Best
Theo
As I am building a 26 preamp, your PCB/Kit is of great interest to me. Please let me know if/when you have some for sale.
Best
Theo
Hi Rod,
I need a pair of boards for each of the following tubes: 26, 45 and 300b. Please advise cost and availability
I need a pair of boards for each of the following tubes: 26, 45 and 300b. Please advise cost and availability
In the application notes it recommends the EpCos 1mH choke, this is available in the USA as digikey part number 495-2733-ND, my question is this is a 4 pin device while the application notes show it as a 2 pin choke, so we need some clarification on how to hook it up between the filtering caps.
Dave, I'll put the information in the App notes, but here's a preview. For 4-pin devices - these are common-mode chokes, use the diagram at the top. If you have a standard choke, use the single winding diagram at the bottom.
If you choose you own choke, you can either use a ferrite type in common mode or differential mode. These are very effective for reducing HF noise. you may suffer from this if your mains is polluted by industrial noise, subway activity etc. Or if there are powerful radio stations in your locality.
Chokes with laminated steel cores are effective against any remaining mains ripple too, although there won't be much of that left if you use 15000uF caps.
.
Attachments
Thanks, I've always had trouble with small common mode chokes cause they aren't well marked.
Here is the datasheet for the recommeded EpCos B82721K2202N1 which is available in the USA via digikey. Its always a guessing game what pins are what:
http://www.epcos.com/inf/30/db/ind_2008/b82721a_j_k.pdf
Here is the datasheet for the recommeded EpCos B82721K2202N1 which is available in the USA via digikey. Its always a guessing game what pins are what:
http://www.epcos.com/inf/30/db/ind_2008/b82721a_j_k.pdf
The transmitting tubes up to 845 [10V 3.25A] have been fully qualified. The GM70 design has been worked out, and will be tested during the week.
The Warm-up time is very stressful for the GM70 version of the regulator - and I have to make sure that it is strong enough for the high reliability you will expect.
I will let you know!
Well, I have to say, Nice going Rod! These things are really pretty sweet. I've heard lots of different DC fil supplies but was really surprised with the degree of change that your circuit brought to my 10Y line stage. Very impressive.
I'll note here for anyone else trying these boards that it's worth it to try flipping the polarity at the filament connections. When I first put the boards in the sound was very clear but the effect was partially due to a drop in LF content. Flipped, the bass came back and everything is balanced and clean.
Most surprising to me was a drop in the distortion you hear 'between the notes' of jammed piano chords. Having a background in piano, it's one of the weaknesses I notice most in stuff I build and is one of the things that reminds me that I'm not there yet. It seems a bit incredible that an "isolated change to a closed loop circuit" could have such a direct effect on the one it doesn't share current with.Yet even my wife is really digging what this has done. She usually goes to sleep at 10 and here it is twenty to one and we're still sitting here listening to Bill Evans. Way to go Rod. Thanks!
I'll note here for anyone else trying these boards that it's worth it to try flipping the polarity at the filament connections. When I first put the boards in the sound was very clear but the effect was partially due to a drop in LF content. Flipped, the bass came back and everything is balanced and clean.
Most surprising to me was a drop in the distortion you hear 'between the notes' of jammed piano chords. Having a background in piano, it's one of the weaknesses I notice most in stuff I build and is one of the things that reminds me that I'm not there yet. It seems a bit incredible that an "isolated change to a closed loop circuit" could have such a direct effect on the one it doesn't share current with.Yet even my wife is really digging what this has done. She usually goes to sleep at 10 and here it is twenty to one and we're still sitting here listening to Bill Evans. Way to go Rod. Thanks!