As you can see, the 60Hz -about- 15dB less in case of V9, than V8.
There are no -visible- sidebands over 1kHz, with the exception of 120Hz component the spectrum is free from hum components, so the overall tone due only tube distortion (which is very low).
I am using the basic CRC raw supply from Rod. No changes were made to anything else when switching from V8 to V9. I had asked Rod earlier whether I could get any sonic advantage by using a choke in the raw supply and he felt I would not since the current involved (250ma) is very low.
He mentioned somewhere that the V9 is less finicky about its raw supply than the V8.
nash
You are right. I hadnt noticed this before. The next time I check, I will do the FFT with a different tube to see whether there is any difference. Thanks.
nash
Yes, the V9 may let in a tiny bit more 100/120Hz. It is a very small amount: across the filament, it might be 6µV rather than 4µV. I don't think that you will hear hear any hum from that, even in a preamp. This difference is the tradeoff for a dramatic reduction in susceptibility of 50/60Hz pickup, and the incremental reduction in the regulator's reaction to the signal at the cathode. The V9 is a competely new design.
Using a larger C value in the Raw DC (second cap) can usually reduce the 120Hz spur back to where it was. This is not just the filtering effect: keeping the input impedance low at low frequencies allows the regulator's error circuit to work more effectively.
Hi Nash - very good to have your confirmation that the V9 was worth the design effort - thank you! The design-aims for the V9 were the lowered susceptibility to 60Hz noise, and a further reduction of the mimimal disturbance to the music-signal (as seen across the ends of the filament). This part is likely to help the natural quality of the sound you are hearing; we cannot get this with a voltage regulator.
EI or Toroid for B+ supply
I'd like to try a different B+ supply for my 01A that has Ale's gyrator+SF. I want to use a choke input supply with full wave 6BY5GA tube rectification and was wondering whether folks here have a sonic preference for an EI or a toroid in this application. Power supply in separate box. Presently using an Antek toroid and TentLabs MEC50 electronic choke. I have no experience with other types of supplies so would like to try.
Also, has anybody used transformers and chokes from Mr. Ogonowski in Poland? http://www.ogonowski.eu/
Thanks. Nash
I'd like to try a different B+ supply for my 01A that has Ale's gyrator+SF. I want to use a choke input supply with full wave 6BY5GA tube rectification and was wondering whether folks here have a sonic preference for an EI or a toroid in this application. Power supply in separate box. Presently using an Antek toroid and TentLabs MEC50 electronic choke. I have no experience with other types of supplies so would like to try.
Also, has anybody used transformers and chokes from Mr. Ogonowski in Poland? http://www.ogonowski.eu/
Thanks. Nash
I'm not a fan of the 6BY5GA. I compared it to GZ34 and 5U4G and both sounded better, so I'd recommend one of those. You can use a 6V supply with dropper resistor(s) if that's more convenient. I'd rate it at 30VA. When there's no centre tap I often use a Graetz or hybrid bridge with 1200v Schottky diodes. https://uk.rs-online.com/web/p/schottky-diodes-rectifiers/8099036. In fact for a preamp stage I just use 4 of these diodes in a bridge, no tube.
I'm perfectly happy with Hammond chokes - good value and available anywhere. B+ transformers are overpriced and I look for second hand ones off ebay - usually some there. Many have a 6.3V winding you could use for e.g. an EZ80/81.
I'm perfectly happy with Hammond chokes - good value and available anywhere. B+ transformers are overpriced and I look for second hand ones off ebay - usually some there. Many have a 6.3V winding you could use for e.g. an EZ80/81.
I would suggest a custom made EI with several sec. and heater (rectifier) voltages to try different rectifiers/chokes. This is what I did and tried to follow what Thomas Meyer used to offer with his Weiss transformers (screens between windings and outer screen).
Andy, I recall reading one of your posts a couple of years ago about your preferring the sound of Sic diodes over tubes for preamp rectifier use. Is this with EI transformers? Since I have to buy another transformer anyway and since one can get EI's and toroids to suit different configurations I asked whether there was a preference soundwise.
Regarding chokes it is my understanding that for a true choke input supply the first inductor of say 10-15H should have a low DCR around 30ohms. That seems difficult to find. What schematic do you suggest following the Sic diodes?
Swak I looked at Thomas' offerings and must check about the screen between the primary and the secondary windings. I know that the Antek AS series toroids have these screens
Thanks.nash
Regarding chokes it is my understanding that for a true choke input supply the first inductor of say 10-15H should have a low DCR around 30ohms. That seems difficult to find. What schematic do you suggest following the Sic diodes?
Swak I looked at Thomas' offerings and must check about the screen between the primary and the secondary windings. I know that the Antek AS series toroids have these screens
Thanks.nash
I can't remember exactly but I think it was swings and roundabouts with tube or SIC diodes. I did prefer a 5U4 for the output stage of an amp.
Rod Coleman is the guy to ask about power supplies, plus a few more who post here.
For choke input, I prefer vacuum diodes, especialy slow-warming damper diodes. THe 6CJ3 and other 6Cx3 series are impeccable in this position. They give a 30s linear ramp-up, after a 30s delay, and despite the high voltage and current handling, the capacitance is very low. Hope there are some still around, but other dampers should also work well.
THe separate screens around primary and secondary, and the ability to connect them separately is likely to be very effective. You should be able to get them custom made locally, like that. Specifying low core flux (a standard feature of high quality audio transformers from Air-Link or Canterbury Windings (the UK makers of such things). I imagine there are others in many locations worldwide.
Thanks Rod.
From the Antek website " toroidal audio power transformers have static shield between primary and secondary coils to improve the isolation and noise interference."
"And they also have the magnetic shield around the outside to reduce the magnetic leakage"
Is this what you are referring to? There is no mention of low core flux except Open Circuit core loss test with some numbers in the download spes section.
https://www.antekinc.com/content/AS-2T230.pdf
Rod, what is your opinion on toroid chokes in tube power supplies and of the Antek ones that they mention are "newly designed"?
From the Antek website " toroidal audio power transformers have static shield between primary and secondary coils to improve the isolation and noise interference."
"And they also have the magnetic shield around the outside to reduce the magnetic leakage"
Is this what you are referring to? There is no mention of low core flux except Open Circuit core loss test with some numbers in the download spes section.
https://www.antekinc.com/content/AS-2T230.pdf
Rod, what is your opinion on toroid chokes in tube power supplies and of the Antek ones that they mention are "newly designed"?
They may work well but I had a bunch like 6DT4 and 6BY5G and they were OK but didn't sound as good as 5U4 or GZ34 or AZ11 or AZ1. AZ1 mesh was the best sounding. 5R4G was a really bad sounding rectifier.
Hi, I think what he might be referring to is this (quote from Vinylsavor, highlighted part):
My favorite is 6CM3 RCA. Highest steady state current of all. RCA is bi-plate, two parallel diodes inside single envelope. Sylvania 6CM3 monoplate is a relabelled 6CJ3.
Another great thing about damper diodes is their ability to handle voltages in the kilovolt range. Perfect for 211, 845, or GM70 amplifiers.
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Antek is low flux, judging from their high primary inductance and very low magnetizing current. Love their toroid power transformers.
Thanks sser2. Going back to my original question EI or toroid for B+ supply, do you think then that an Antek AS series would be a very good choice sonically for B+ or an EI with the dual screens, with a choke input in mind? I have used Antek AS in over 9 amp builds without a problem, but as the expression goes "Ignorance is bliss" so feel its best to draw on the experience of the folks here.
nash
Antek toroid hands down. I have many vintage tube power transformers. None has primary inductance comparable to Anteks, for the same power. None has same low secondary DCR. Most EI transformers are noisy, unless they are military style sealed potted units. Toroid have lower stray magnetic fields. I cannot see any single advantage of EI vs. toroid. The only problem is difficulty in finding one that has exact voltage you need for your project.