I want to know where to allocate funds when specifying transformers for a tube amp build (read: what corners to cut).
At the risk of oversimplifying things... From what I understand the output transformers make the most difference sonically; however, I know that amps are the sum of their parts and each typology would stress different aspects of each component. To get the best OPT possible, would you go with a slightly lesser quality choke or power transformer? I'm leaning toward cutting corners on the choke but I would like to get a second opinion.
When I imagine cutting corners, it would not be on choke specification... more on overall quality (I guess???)... for example, forgoing the Hashimoto choke for an Edcor or Hammond. Obviously, there will be a difference...
I'm heading to Japan next month and specifically wondering if I should get some nice big ISO OPTs and General Transformer (formerly Noguchi Transformer) chokes or get slightly lesser ISO OPTs and ISO chokes. Am I overthinking this?
At the risk of oversimplifying things... From what I understand the output transformers make the most difference sonically; however, I know that amps are the sum of their parts and each typology would stress different aspects of each component. To get the best OPT possible, would you go with a slightly lesser quality choke or power transformer? I'm leaning toward cutting corners on the choke but I would like to get a second opinion.
When I imagine cutting corners, it would not be on choke specification... more on overall quality (I guess???)... for example, forgoing the Hashimoto choke for an Edcor or Hammond. Obviously, there will be a difference...
I'm heading to Japan next month and specifically wondering if I should get some nice big ISO OPTs and General Transformer (formerly Noguchi Transformer) chokes or get slightly lesser ISO OPTs and ISO chokes. Am I overthinking this?
Yes, in price. 😉
How much you have to spend on transformers is entirely your business.
jeff
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If youre cutting corners you can do it in the power supply more than the audio portion. Antek toroids for power and use silicon instead of chokes. Mount ‘em up under the chassis if you can’t stand the sight of them. Then you can afford the OPTs you want.
The choke will certainly be (much) less critical than the output transformers.
But it will also (or at least should) be much less expensive.
But it will also (or at least should) be much less expensive.
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LOL. Yes, there's a budget and shuffling things around before my trip!
Nice to see this in writing!
Well, I started out adapting the Baby Ongaku for stereo but then decided to build it as designed - as monoblocks. So I bought another power transformer, and now need another choke or two. I have a nice Hashimoto for the stereo build but can't justify buying another so thinking I'll get two smaller and slightly less nice chokes and save the big Hashimoto choke for another build.
Yes pretty much... just with that little tuning cap for the B+. I was looking at a choke from the company that I'm going to order the ISO OPTs from that is 16H and rated for 120mA (150mA max) and 500VDC. It doesn't list if it was designed for cap or choke input explicitly but this seems like it will work, no?
Also, specifies 1.5kV AC for 1 second...
Also, specifies 1.5kV AC for 1 second...
I hope you are aware that the choke for a chokeinput PS must be designed for the large ac swing ( LC input). Chokes intended for smoothing only (CLC) can be made much smaller and cheaper. Make sure the choke you buy is suitable for your purpose.
Without global negative feedback, the output transformer is the Heart of the amplifier.
Cut Corners? Try a 3 chambered human Heart.
With global negative feedback, some output transformers can be Very Tricky when you compensate the negative feedback.
Do not get discouraged, I have heard different amplifiers that used:
Electra Print Audio, One Electron, Lundahl, Edcor, Hammond, Monolith Magnetics, and others.
They all sounded fine, some better than others.
To a great extent, you get what you pay for.
The real key is matching the transformer to the right tube type, the right plate current, right plate voltage,
and in the case of push pull . . . exactly matching the quiescent currents of push and pull.
Your Mileage May Vary
Cut Corners? Try a 3 chambered human Heart.
With global negative feedback, some output transformers can be Very Tricky when you compensate the negative feedback.
Do not get discouraged, I have heard different amplifiers that used:
Electra Print Audio, One Electron, Lundahl, Edcor, Hammond, Monolith Magnetics, and others.
They all sounded fine, some better than others.
To a great extent, you get what you pay for.
The real key is matching the transformer to the right tube type, the right plate current, right plate voltage,
and in the case of push pull . . . exactly matching the quiescent currents of push and pull.
Your Mileage May Vary
The output transformer is the most important single part. You can have the best circuit design and a cheap output tx will ruin the sound. Conversely, a good tx can reveal a bad design. Buy the best one you can afford that fits the design and you can always upgrade the other cheaper parts as time goes by. Things like expensive coupling caps and top of the line connectors are nice but can wait. The difference between a $1 resistor and a $10 resistor is a small you are better off using the less expensive ones to start. If you fall in love with the amp you can upgrade as funds allow. Build a good power supply too, you can’t run a race car on bad gas? Right? Same for an amp, it is the power supply that fuels the amp, metaphorically speaking. But if you change the amp the power supply can be adapted most likely. I use Antek power transformers mostly because they are less expensive and I’ve had great luck with their quality and performance. As long as a choke is rated for the inductance and current you need they are pretty much the same, after all it’s just wire on a transformer core to oversimplify. AliExpress has lots of them cheap and they do the job for me. Most importantly, don’t over think to the point of not getting anything done! If it comes out wrong just try again!
I never had issues using Hammond or Edcor for any power iron. I use Edcor for custom designs because they are a little bit reasonably price for one offs. sometimes it takes a little bit of time, but they do a decent job. Even making certain signal transformers which their core material is very similar to UTC. But I don't consider UTC signal transformers audiophile quality either. They what I call commercial quality. These level of transformers are used on purpose in pro audio gear because they slope out undesirable frequencies for the instrument recorded. But with power iron, Its not going to matter, and Edcor has never sent me something I sent back to them to redo. I can't say the same with hammond, though the last two decaades they haven't send me bad stuff either.
I would get the ISO or Hashimoto output tranformers, and build an Edcor power supply with quality parts. Because anyoe can build good power iron. But not so much for output transformers. That takes much more skill for wideband audio.
< I would get the ISO or Hashimoto output tranformers, and build an Edcor power supply with quality parts. Because anyoe can build good power iron. But not so much for output transformers. That takes much more skill for wideband audio.
This. Hammond or Edcor or whatever for the PSU as long as the parts are correctly rated. Put the money into the OPTs. If you are in Japan get something tasty. I have a pair of Tomiko SE OPTs which are very nice and were quite cheap.
This. Hammond or Edcor or whatever for the PSU as long as the parts are correctly rated. Put the money into the OPTs. If you are in Japan get something tasty. I have a pair of Tomiko SE OPTs which are very nice and were quite cheap.
as I said before, NO, they are not the same! It is not enough to just know inductance and current! A choke designed for LC input must be designed for it, a choke that is designed for smoothing only, as in CLC, will most likely saturate if used as LC input choke because (Bdc+Bac=Bmax = what counts).
For example, chokes with the same rated inductance and dc current could be designed:
LC choke, Bdc 0.8T + Bac 0.6T = Bmax 1.4T (bigger and more expensive)
CLC choke, Bdc 1.1T + Bac 0.3T = Bmax 1.4T (smaller and cheaper)
If you would use the CLC smoothing choke at rated current for LC input it would have to operate with Bdc1.1T + Bac 0.8T = Bmax 1.9T = saturate
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The Hammond 193H 5H @ 200mA choke is a good one.
It may, or may not, meet your need for a choke input filter.
But I regularly use it as a choke input filter for 70 to 80 mA.
It is Quiet.
It filters well.
It measures well.
Just one example of many manufacturers good chokes.
I challenge any of you to find any data sheet statement that the 193H is designed to be used as a choke input filter.
Oh . . . it does have the word: "Reactor" on the choke label (Aren't all chokes a reactor; inductive reactance anybody?).
If you use it as a choke input filter for 90mA to 200mA, then . . . Your Mileage May Vary . . . I never tried it at those higher currents.
Do not say that a choke input filter for a Hi Fi/Stereo amplifier must have a data sheet that says: "Swinging Choke".
Hi Fi/Stereo amplifiers are Nothing Like a "Key Down, Key Up, CW RF Transmitter"
No Swinging Chokes needed for Hi Fi/Stereo amplifier linear power supplies . . . Just my opinions and my experience.
True, a switcher power supply can be a different animal when it comes to chokes specifications and technology.
A simple rule to think about:
Do Not wonder why you get the poor results you got when you stressed your parts to their specified maximum limits.
Usually you get un-reliable component life, poor performance, and the amplifier might not sound good either).
It may, or may not, meet your need for a choke input filter.
But I regularly use it as a choke input filter for 70 to 80 mA.
It is Quiet.
It filters well.
It measures well.
Just one example of many manufacturers good chokes.
I challenge any of you to find any data sheet statement that the 193H is designed to be used as a choke input filter.
Oh . . . it does have the word: "Reactor" on the choke label (Aren't all chokes a reactor; inductive reactance anybody?).
If you use it as a choke input filter for 90mA to 200mA, then . . . Your Mileage May Vary . . . I never tried it at those higher currents.
Do not say that a choke input filter for a Hi Fi/Stereo amplifier must have a data sheet that says: "Swinging Choke".
Hi Fi/Stereo amplifiers are Nothing Like a "Key Down, Key Up, CW RF Transmitter"
No Swinging Chokes needed for Hi Fi/Stereo amplifier linear power supplies . . . Just my opinions and my experience.
True, a switcher power supply can be a different animal when it comes to chokes specifications and technology.
A simple rule to think about:
Do Not wonder why you get the poor results you got when you stressed your parts to their specified maximum limits.
Usually you get un-reliable component life, poor performance, and the amplifier might not sound good either).
6A3sUMMER
If you use a 200mA dc rated choke at only 40% rated current then naturally the window left for Bac increases more than you will ever need, so, good for you.
I got burned by purchasing 2 chokes rated 500mA dc, saturated and was not usable for LC input even with 20% derated current wich allready ment over 40% less dissipation.
After that i found it necessary to get more info than just rated dc and inductance before the purchase.
If you use a 200mA dc rated choke at only 40% rated current then naturally the window left for Bac increases more than you will ever need, so, good for you.
I got burned by purchasing 2 chokes rated 500mA dc, saturated and was not usable for LC input even with 20% derated current wich allready ment over 40% less dissipation.
After that i found it necessary to get more info than just rated dc and inductance before the purchase.