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I was writing a response to a question, and had to explain my use of a higher frequency AC regenerator.
I use a PS Audio P600 with the alternate board which allows any AC frequency output from 60 Hz up to 120Hz. (instead of only the standard 60Hz output)
I find it improves the sound of my digital gear..
And yes a search of this may yield results for those interested, as it has been discussed a little in the past.
SO.. Anyone else currently use a higher AC frequency? OR am I the only one...
And ANY other makers of stuff which can be used to adjust the AC power frequency besides my old P600?
Here is the text of the post But it is a long read with little to offer. But I include it so you can waste your time. LOL
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Recent post in digital drive:
....((edited to include just the parts about alternate AC frequency))...
For my digital gear...
The conditioner which I am really glad I was able to find was not so much brand name as the fact it is able to adjust the output frequency.
Adjustable AC output frequency is a very very rare bird in a conditioner.
The PS Audio P600 I found used (and long out of production) had an added (optional when new) board which allows it to output any frequency AC sine wave from 60Hz to 120Hz.
I am using this AC regenerator at a 110Hz Sine AC output on only my digital components.
I read about 'alternate' AC frequency use in a blurb in Stereophile years back. The gist of the article was the higher AC frequency power input made for better sound. It made so much sense to me I decided I just had to try it. But finding any conditioner with such an ability is tough to do!
(I would guess liability of not using 60Hz is part of the problem for the makers, plus endless queries about HOW and WHY to use it.. PITA I would think. Plus certain types of power supplies do not play well with this sort of alternative AC)
The PS Audio P600 normally was not able to do this, but with an optional board (originally designed mainly for turntable use ?) I am able to adjust the entire output of the P600. The P600 was just about the ONLY regenerator with this even as an option. I know of no other AC conditioners capable of alternate Hz output. AND the board option was not common, and is no longer available even if you find a P600 without it.
So, that really makes it near impossible to find such a device.
So.. How can I recommend a device you cannot buy? (Plus I paid $1000 for it 5 years ago and considered that a steal! What with its rarity and uniqueness)
With this 110 Hz in I found my old Adcom DA700 is the equal of a new $2,200 unit. Not better, but equal (My Sony SCD777ES is a tiny bit better than the Adcom and a $80 used CD changer off eBay, Barely.
SO... MY recommendation is go find the rare needle in the haystack, which if it breaks you will be totally SOL... LOL
I am surprised no conditioner makers have such a product. It does need to be a regenerator to do this. And PS Audio is the main product maker for this type. Someone should ask them for this AC variable frequency to be added to the current product line!!
Follow Ups:
77Hz fine tuning bass/hf balance.
"And ANY other makers of stuff which can be used to adjust the AC power frequency besides my old P600?"
A VFD? might be harder to set it up though
I very recently had my Acoustat servo amps rebuilt and the high-voltage trannies were replaced with larger uprated transformers. Much to my chagrin, when I got them home and plugged them in, the transformers hummed and buzzed to the point of being an annoyance. Clearly audible from the listening position during quiet passages in music. I tried tightening up screws and all the obvious stuff. After a week or two, it finally struck me that it might have something to do with line voltage. The high-voltage transformers are custom wound and it occurred to me actually look at the stickers on them the manufacturer had affixed to them. Right there in black and white it said they were 115v input. Well, my PurePower re-generator was set to output 120v/60hz. I dug out the manual and read up on how to change it, which I did and set it to output 115v/60hz. Immediately the buzzing and humming went almost entirely away. No longer an annoyance. One of the four transformers still buzzes a little, but no big deal to me. According to the display on the PurePower unit, line voltage from the wall usually runs at around 125v.Edit: Sorry, your post was about frequency and not voltage. I should've read more closely before reply. Although, now you've got me wondering about playing with different frequency settings on the PurePower.
Edits: 03/24/16
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nt
Your old (pre self limiting) Corvette. You can run it up to 300 rpm over the redline. But you sadly found out running up 400 rpm just blew up your engine. You took it up to 300 rpm over numerous times. but 400 just was the step too far.
Speaking of steps. stepping UP to the edge of the Grand Canyon. No problem. A half step further, and you are sleeping with the angels.Another car example: Tire pressure too low? Not a problem at even only 14 psi.. Drive all day. When that same tire on the same roads started it's final day at 13 psi. After an hour It blew out. Who would have thought?
Nascar is a prime bunch of endless examples of those tiny 'too far' things that causes a series of further events and a crashed car.
I can go on and on, but the thing is there are plenty of examples of specific points where things change drastically. This guys transformer just happened to be at such a point between 115 and 120 volts
Edits: 03/25/16
all I was saying is that I am surprised in this particular case that only a 5 Hz difference is "too far" or "too much". For example, if you are one foot from the edge of the Grand Canyon, it would be ok to step forward 6 inches. But I certainly don't doubt you at all, in this case.
So, I reset my re-generator back to 120v and the buzzing came back. Reverted to 115v and buzz substantially reduced. The buzzing never went completely away, but is very much less noticeable @ 115v output from the re-generator. I am by no means expert in physics of transformers, but one thing to offer is that these are not your run of the mill garden variety transformers. These amps are specifically designed to drive electrostatic panels. Those trannies output thousands of volts not hundreds. Again, not sure if that has any bearing on what I am witnessing, but I am here to tell you that reducing the voltage does have an effect in my case. Quite audible. There may indeed be other factors at work here, but in the end the transformers run quieter and that's all I really care about.
Are these direct-drive OTL amplifiers? Oh, I guess you did mention they are from your Acoustats. Very cool. I use Beveridge 2SW speakers in one of my systems, also direct-driven. Although such amplifiers do put out high-ish voltage, sometimes the output voltage is much further increased after the secondaries, by use of voltage doublers, which is at the expense of current. But very very little current (at very very high voltage) is required to drive an ESL directly. Anyway, whatever one might have expected in terms of the effect of the AC voltage on vibration of the transformer, I don't doubt your direct experience. And those are probably unobtainium transformers, should one of them blow, so you are right to be conservative. I feel the same way about the power transformers in the Bev DD amplifiers.
BTW, Beveridges also very cool. Working ones are scarce as hens teeth. I'd love to hear them. Too damned bad we live so far apart.
You are right. Direct drive OTL's. In reading Jim Strickland's notes on the copy of the schematic I have, the transformers output ~2,200 volts. He then employs voltage doubler to bring what the tubes see to ~5,000 volts.
So, 3200V across the stators. But they are not like conventional ESLs in that the diaphragm does not carry a charge; the diaphragm is low impedance (coated with aluminum)and driven, I think, along with the stators. Why this works, I have to sit down and re-think every time. However, because of the lack of high tension on the diaphragm, in fact the panels have lasted for 30 years, by and large. It's the amplifiers that cause problems. I am endlessly thankful for the help of "Steve O", an inmate on TubesDIY, who is also an EE and an owner of Bevs. Steve held my hand long distance as I solved a vexing problem with one of my amplifiers, which after all was done turned out to be a bad solder joint on one capacitor in the output circuit. After a while, I figured out it HAD to be something stupid like that, because I had been through and rebuilt the entire circuit, pretty much, and the amp was still oscillating.
If the buzz is still there you probably have a ground loop. Regenerators act like an amp circuit. I lifted my ground to my regenerator per PaulMcGowan and gone.
After talking to him and Charles Hansen of Ayre I have lifted all my safety grounds with excellent results. What a difference.
ET
Wouldn't ground loop be audible through the speakers? As far as lifting the safety ground, no way. Not with something that outputs 5,000 potentially lethal volts. Out of the question.
I never use regens onan amp. I'd consider if the load used less than half the potential current of the regen.
Regens are notorious for squashing dynamics when you even get just peaks near the max potential of the regen.
ET
The PurePower unit runs everything through lead acid batteries which actually are capable of delivering more current than is available from the wall - for short periods obviously. As such, things never poop out. I've never experienced squashed dynamics with this setup.
I think you misunderstood me. It's about the output of the regen not it's input source. I think 3000 Watts out is the largest one made by the manufacturer you have which is hefty and would provide 25 amps of current. Still no regen made by anyone should be used with amps if you are going to use much more than half to two thirds of the regens potential output. Headroom for peaks is critical. That's when dynamics get compromised.
Just add up the consumption in Watts of all the devices plugged into it. Knowing the consumption of all you plan to plug into it should be a very important factor before purchasing a regen.
ET
I think I understand now what you were saying. I did all that volt amps watts computation before I bought it for exactly the reason you said and the 1500+ model offered more than double my estimate. There is a LCD on front which, among other things, constantly shows % of capacity used. Most of the time it never goes above 25%. If all components in the system are powered up it will sometimes hit 50%. I've never seen it exceed 50% on the display. No idea how accurate that display is, but it does suggest at least that my estimate vs. its capacity may be where it was intended to operate.
Awesome. My P 300 has that too and it reads slow so it won't show peak draws but it never goes above 10-20% so I'm fine. Sounds like you have the headroom you need as well. I was told by someone wiser than me that these regens are like an amp and need headroom. They need it even more when power amps are connected.
ET
So far I've been really happy with the PurePower, which is a good thing as they have a fairly poor record of customer service. This is my second unit purchased from them. The older one is supplying power to my plasma. Actually, this is my third unit. The very first one suffered some internal shipping damage and did not function properly. They hadn't been in business very long at that point and customer service was quite good as they were trying to build customer base. The defective unit was replaced PDQ with no hassle. Since then I've read some real horror stories about servicing issues. Knock wood, no problems here. Regarding peak supply, the use of the batteries in their design and their ability to provide a little extra insurance in addition to the excess capacity against peak draw was a major factor in descison to go with PP as I knew I wanted to run the servos through it. So far it's worked out fine.
Most electrical appliances are labeled to be used at 115V or 117V, and it is not uncommon for line voltage in the US to exceed 120V. This small difference usually does not cause a problem. Anyway, in your case, it apparently did. Might be interesting to turn the P600 back up to 120V, to see if you can reproduce the phenomenon.
Me too
ET
I use a P-300 on my sources and quickly found it sounded best at 120HZ sine wave on my phono preamp or CDP.
My unit also has balanced power and was upgraded by Cullen circuits in 2008 with better outlets, caps and a remote control.
If the power is interrupted at the house it resets to 60HZ and you can tell something isn't right. The easiest way to notice is the image gets smaller.
ET
At one point, I read that increasing the frequency of the input AC increases the filtering efficiency of your power supply, but I don't see how that would actually be the case, unless one is using a choke input filter or one where the filtering is largely done by inductors. Otherwise, the impedance of a capacitor (the major filtering device used in modern PSs) goes down when frequency goes up. Maybe the rectifiers work better at the higher frequency. Anyway, I have a P300, and I don't mess with the frequency of the AC. Obviously, you don't want to do this with a turntable motor.
Depends on the type of TT motor actually. I don't know why, I ll let the engineer types hash that out. I just know that for my setup it's (120 hz) what sounds best. I disconnected the fan too per Paul too. Very noisy. I never use more than 10-15% of its potential.
ET
Because the filter capacitance is in parallel between hot and ground, the lower impedance at 120Hz vs 60Hz permits a given capacitance to double its filtering action at 120Hz vs 60Hz. "More" of the AC is sent back to ground at the higher frequency. Earlier, I had not taken into account the parallel connections of the capacitance. Personally, I would rather just double the capacitance, if I felt that was needed. That said, I do like the effects of my P300 putting out plain old 60Hz/120V.
You wouldn't want to do it into an AC synchronous TT motor, because that is designed specifically for 60Hz input. Possibly the result of putting 120Hz AC into such a motor would double or halve its speed, or burn it up. (I'd have to have another think on this.)
Yes, assuming the same loading, the 120Hz sine will allow for half the voltage ripple on the unregulated rail since the cap gets refreshed twice as often.
Yes, that is why. Shunt caps shunt more efficiently as the frequency is increased. Series inductors are also more effective at blocking higher frequencies. Also, a higher frequency is easier on the iron of a transformer, as saturation is also less likely to occur - that's why transformers rated for 60Hz don't work well at 50Hz, but transformers rated for 50Hz work fine at 60Hz.
Twice the pulses of balanced AC is a good thing. Here is info onsynchronus AC motors.
ET
"""Some P300 users have discovered that these devices are a splendid source of pure AC for running their AC synchronous turntable motors. Indeed, the more expensive Walker motor-drive, designed by Dan Fanny of AHT, works on the same principle though it has a lower power output and it can't be used for powering multiple components.
For the 33.3 RPM speed the Power Factor (line frequency) must be set to the 60 Hz default setting. Some turntable manufacturers such as Walker, Basis, VPI and Rega make turntables with AC synchronous motors that are stable when used at a higher line frequency. This means that dialing in 80 Hz, or 81 Hz to be more precise, will result in an increase to the 45 RPM speed. However other turntables with synchronous motors that use a certain type of speed control circuitry could be damaged by prolonged operation above 80 Hz. Among these are Roksan, Merrill and others, which can still be operated safely at the 60 Hz setting. Of course turntables using DC and non-synchronous motors won't be affected (and the speed won't change) by altering the line frequency. Likewise CD players and transports should not be affected. When in doubt, ALWAYS consult the manufacturer.
In current P300 units, there is no way to set the Power Factor to exactly 81 Hz. Some users have found the 80 Hz setting to be close enough to suit them. The good news is that all Power Plants manufactured after October '99 will be programmable to 81 Hz, for exact 45 RPM turntable speed, though it won't be fine-tunable like the Walker unit."""
I use a Walker on my Lenco, and all my other turntables (4) are vintage Japanese direct-drive types which have internal speed control mechanisms of one kind or another. So I feed the DD turntables good old 120V/60Hz, or 100V/60Hz from a step-down transformer for those built to the Japanese standard. My P300 is, however, one of the later ones that would allow adjustment of frequency, up to a point. (I thought it worked in 5-Hz increments, but I have never played with that adjustment.)
Mine goes from 50-120 one Hz at a time. 120 really widens and focuses the image and it's easy to notice the life lost if you will if the power gets interrupted where it resets to 60.
ET
if only because so many report a positive result. (The "idea" being to raise the AC frequency from 60 to 120Hz.) Is there something magical about doubling the frequency from 60 to 120, or do you hear a gradual improvement if you increase the frequency in small jumps, stopping at 120? And on what types of gear? (preamplifier, cdp, etc)
Thanks.
Edits: 03/26/16
I imagine it increases little by little. Much easier to hear when you jump from 60-120.
Again these are subtle but pretty easy to hear. I get the best improvement in image which I consider the final frontier if you will in sound improvement.
ET
I had thought about upgrading the duplex outlets on my P600, but the ones on it (I bought it used, so I do not know if they are the original) The outlets on it seem fine. Very tight grip on plugs. SO I left them alone.
One thing about my P600 I tried a higher level Pangea powercord. THe AC9SE vs the Pangea AC9.. The AC9 sounded better on the P600 than the AC9SE.
Yes upgrading the power cord helped a lot. I use Richard Gray unshielded power cords.
ET
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