The Byrith amplifier uses off-the-shelf Lundahl transformers, which are not stupendously expensive, but I have no clue as to whether they have a US distributor. I've seen a list price for them at around 140€ a piece. That amplifier achieves a full power bandwidth (-1db/+0dB ref 1kHz) of 20Hz to 25kHz and 16Hz to 40kHz at 10 watts. That's not bad.
If you stick to more conventional ultralinear topologies there's lots of off-the-shelf iron to build a good amplifer around from the likes of Lundahl, Hammond, Edcor, Monolith and so on. Prices range from beer money to exorbitant.
edit: KandK Audio seems to be the US distributor for Lundahl. The LL1663 seems to go for USD145.
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Too small, that core will do < 150W at the spec you want. You need 1500-2000VA core.
The main problem is with the mindset of regular USA consumers slowly formed by petro dollar policy. Leaders are in effect helpless in this regards.
Wrong question. Is there a a transformer with the same or better specification for a topology similar to an MC240. Answer depends on what you want to do, commission a transformer house or DIY.
Monolith Magnetics if you want a sure thing. Probably others can chip in on other reliable transformer house. You have to remember they serve a very small price no object market just to survive. As Tubelab said, you can always gamble on winders who profess ability to deliver but nobody can give any reliable prediction on your chance of achieving MC240 spec or better. Those winders doing quality transformer repair works are also shrinking in numbers leaving those willing to do the job as cheap as possible.
Now DIY is both time and money. You learn the art, invest on relevant measuring equipments and iteratively make transformers until it meets the spec you want and reliable for reasonable usage. I think one would need a special grace from The Lord Himself to DIY a successful transformer first time around, even if all the technical spec like core, winding, sectioning and interleaving is available. We know Macintosh had at a reliability issue for a few years. Post what you do here and many will chip in to help you. Many members with extensive experience on transformer here (conut me out) but usually they refrain from answering hypothetical questions.
If you read the post you'll see that the photos were not completed, he added more wire to it. And the MC275 is < 150W and that's said to be the best amp every made by some.
We were still on the petrodollar in the 1940s/50s/60s when the great McIntosh amps were invented and sold for $200. We had a better national (USA) work ethic and a more educated citizenry during those times. Now we only know how to hire someone in China or India to make something for us. My guess is that most NEW technological inventions now come from India and China, and only because the USA outsourced all it's manufacturing and technology to those countries. This is the globalism vs nationalism conflict and maybe Trump can bring some transformer winding factories back to the USA and alone with them some world class engineers.
No, it's my question. I know what I'm asking for. If I can DIY the transformer or give the instructions to the best transformer manufacturer (I'll be most are in China) then I'd want to just clone the MC240 or MC275, not try a less proven DIY design.
I'm not sure what Monolith Magnetics means? But you can test the transformer's electric properties just like you would test any amplifier's OT or just like people refurbish vintage McIntosh transformers, they have the specs and values that they need to meet. It's not difficult and people are restoring McIntosh amps all the time and testing the OTs to see if they are up to standard. Any DIY OT would be measured the same exact way. A smart person would have an agreement with the transformer manufacturer to meet the specs or full refund or free redo.
Smarter to just use the proven classic designs, then you know exactly what to do and exactly what the result will be. The only variation would be as a result of the builders inability to follow instructions or incompetence. Seems like the McIntosh amps have a higher reputation now than in the 90s and early 2000s and I like the one I have a lot so that's what I would try to do if I can figure out the transformer.
If there is another proven design that I can copy that is as good as the MC240/275 in all aspects then which is it? I'd rather measure twice and cut once.
I'd be interested to see how a toroid OT copes with MC240 or MC275 schematic with no modification whatsoever. You find cheap transformer makers in China, great ones are in Europe and Japan. Ever heard the term Shanghaied? You have Intact Audio, Edcor, Electra Print and a few others in the States, but I doubt they keep stock of exotics for a onesey or twosey order. To find Monolith Magnetics click here.
I tried to show you the map as I see it. It's your time and money, decide as you wish, I have no problem either way you go. Good luck. Show us your build attempt, we'll help you along the way as we can when you encounter problems. Just be mindful to all safety cautions associated with building a medium voltage tube amp.
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As I understand a toroid for a OT is not going to be hugely different than standard wound OT. The difference will be in the shape and properties of the magnetic field and the capacitance and resistance, stuff like that, it's still a transformer, which steps up or down voltage. And his wasn't just a toroid it was unity coupled based on the McIntosh specifications.
Toroidal and EI cores both present their own challenges when it comes to making transformers with wide bandwidth. Here seems to be your unity coupled toroidal OPT: Specialist: VDV-1070-UC-PPS
That amp uses the 845 tube originally intended for radio transmitters. I designed and built my own. It makes almost 40 WPC and runs on 1100 volts. Are you ready for the safety, layout and assembly issues associated with that level of voltage?
In some designs it make sense for two reasons. The power supply by nature is full of electrical noise so it can be good to keep it away from sensitive electrical circuits. I reasonable sized amps this can be mitigated by careful layout. The other reason, and the one that I used in my 845 amp is that putting the power supply and two large output transformers and the power supply all in one box makes for something too large and heavy to me easily moved. Pictures of my DOY 845 amp are enclosed. I made it almost 15 years ago. My woodworking skills are a bit better now.
It is not uncommon for small companies to invent buzzwords for their new, or possibly unique design. I have done the same. Carver built some solid state Magnetic Field amplifiers in the 80's, I had one. It was a somewhat conventional class G (rail switching) transistor amp with a crude 60 Hz switch mode power supply....the Magnetic Field part.
Unless the schematics are available somewhere, nobody here can tell you if it can be DIY'ed without taking one apart......The specs tell me that is is likely a solid state amp.
Yes, tubes are still being made, however only the few popular tubes that are still in high demand are being made. This is mostly tubes for guitar amps. The use of TV sweep tubes like those in the MC3500 was never popular in audio until AFTER the solid state revolution, so none of them are currently being made.
I might know what I'm doing when it comes to tube amps, cell phones, or any of the other things that I did for the past 50+ years, but I'm a basic rookie at plenty of other things that interest me.
When I'm reading forum posts in an area where I'm no expert, I will read or scan through some of the related posts that have been suggested, or at least Google words, terms, and phrases that I'm not familiar with.
Reading the thread on the 200 watt SE amp, sticking the words "Monolith Magnetics" into Google or even reading some of the answers here would have told you that they are one of the best custom tube amp output transformer winders in the world, and that they WILL do one offs......for less than the cost of a Corvette. From the first hit on Google, and their web page:
MONOLITH MAGNETICS is specialized in the design and production of audio related magnetic products such as output transformers
That amp is a modernized improvement of an older design. I never built it, but do have the Lundahl LL1663/PP transformers which I used in a small TV sweep tube amp of my own design. It makes about 35 WPC and does sound quite nice. Those transformers are NOT Mac unity coupled designs, but are a cut above the generic stuff, and DO make for a good simple amp build.
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And how much DC current imbalance it will tolerate before saturating. Unlike EI and cut C-core, most toroid cores comes with high permeability and no easy way to add a gap, except specially built ones. Tubes will behave slightly differently on supply variation and degrade over time with no guarantee for the match to hold. I did not mean huge difference or other unproven schematic. You may encounter a problem, hopefully none or nothing serious. As I said, I'm very much interested on the solution that works for you. Again, Good Luck.
I've been doodling a little here and unless I've made a mistake it looks like with a pair of 100W 2.5k:8 transformers and a pair of 813s, it would be simple to get 200W out of a Twin-Coupled arrangement. That'd be a pretty cool amp.
I mean, I'll probably never make an amp with big transmitter tubes but if I did, that's how I'd do it.
Looks interesting and not too expensive and not so unobtainable like everyone says, but I noticed that the frequency response isn't as good as the vintage mc240 that has these specs:
16 ~ 40,000 cycles +0, -0.1 dB at rated power.
16 ~ 60,000 cycles +0, -0.5 dB at rated power.
10 ~ 100,000 cycles +0, -1.0 dB at half rated power.
The link you gave (mennovanderveen) has these specs, but it could just be that they are only giving a rough estimate since perhaps they didn't do more exhaustive testing...
Frequency range : 0,1 Hz to 440 kHz (-3 dB)
I think toroid transformer properties are well known, not by me, but they seem to be used in a lot of amplifiers and other things, so people (and computer simulations) know about them.
1100 volts at what amperage? I was unlucky enough to touch a bare wire in the attic last month... I didn't die but it wasn't fun and let out a pretty good grunt that I'm sure the neighbors could hear. I'm pretty sure that was 120v 15amps... You realize that high voltage is harmless unless it has high amperage too? The static sparks you get from your finger to the door knob or in your clothes right when you take them from the dryer have much higher voltage than your amplifiers. Remember those cool globes with what looks like an electric line spark in them, they are called plasma globes, they have 5000 volts and little kids play with them, they are harmless because they have super low current. They are called Van de Graaff Generators and go up to crazy amounts of voltage. Here's one that produces 600,000 volts but only 10 microamps of current, so it's harmless.
"High Voltage Information
While the voltage produced by this unit is high, the actual current (amperage) produced in this device is is very low. Electrical currents of this type are known as Static Electricity. Although there is little danger from the electrical charge itself, it can still produce a shock that may cause secondary harm like a small shock causing you to jump back and hit your head on something. People with cardiac pacemakers should never operate any high voltage equipment or approach it while in operation as the electrical fields produced could cause the pacemaker to be damaged or malfunction."
Van de Graaff Generator - 600 kV : United Nuclear , Scientific Equipment & Supplies
This is where my science education pays off. Most EE's know this.
"The amount of voltage required for a 2 millimeter spark from your finger to the doorknob is about 6000 volts. Since the current is very low, there is no real danger from such a high voltage."
Static Electricity Sparks by Ron Kurtus - Physics Lessons: School for Champions
"High Voltage Information
While the voltage produced by this unit is high, the actual current (amperage) produced in this device is is very low. Electrical currents of this type are known as Static Electricity. Although there is little danger from the electrical charge itself, it can still produce a shock that may cause secondary harm like a small shock causing you to jump back and hit your head on something. People with cardiac pacemakers should never operate any high voltage equipment or approach it while in operation as the electrical fields produced could cause the pacemaker to be damaged or malfunction."
Van de Graaff Generator - 600 kV : United Nuclear , Scientific Equipment & Supplies
This is where my science education pays off. Most EE's know this.
"The amount of voltage required for a 2 millimeter spark from your finger to the doorknob is about 6000 volts. Since the current is very low, there is no real danger from such a high voltage."
Static Electricity Sparks by Ron Kurtus - Physics Lessons: School for Champions
Ok, I looked up the "Monolith Magnetics"... those kind of shops charge a lot for something that costs them a little, definitely not DIY friendly. The best place to get cheaper transformers is from a place like this, since in my previous post I've shown where a unity coupled transformer to the original McIntosh specs cost just $36 to build DIY. He did it in a toroid format, but the same thing could be done with a C-core or air core or other. I don't really know the specifics but I think the number of windings changes and other parameters, but they have computers and winders that do all this work nowdays and a person in China working for $.25/hour operates the machine, then someone in NY buys the transformer and sells them for a lot of money.
This 70 watt unity coupled transformer is only $200 euros. Specialist: VDV-1070-UC-PPS
This 70 watt unity coupled transformer is only $200 euros. Specialist: VDV-1070-UC-PPS
I would suggest that you STOP NOW before you kill yourself.
You clearly need extensive and substantial education with regards to working with high voltage, because you are on a very scary path.
A Van de Graaff Generator IS IN NO way comparable to the voltage/current used in a high voltage tube amplifier.
Not trying to rain on your parade, but we certainly don't want any DEATHS to come from this.
You clearly need extensive and substantial education with regards to working with high voltage, because you are on a very scary path.
A Van de Graaff Generator IS IN NO way comparable to the voltage/current used in a high voltage tube amplifier.
Not trying to rain on your parade, but we certainly don't want any DEATHS to come from this.
Do all common wattage amps run on kv ranges of voltage? Even solid state amps? Are you saying that there are 1100v in your amp going through the speaker wire? Where exactly is the 1100 volts in the circuit in the 35/40 watt amp you said you built?
I'll post this one more time in case you missed it:
I would suggest that you STOP NOW before you kill yourself.
You clearly need extensive and substantial education with regards to working with high voltage, because you are on a very scary path.
A Van de Graaff Generator IS IN NO way comparable to the voltage/current used in a high voltage tube amplifier.
Not trying to rain on your parade, but we certainly don't want any DEATHS to come from this.
I would suggest that you STOP NOW before you kill yourself.
You clearly need extensive and substantial education with regards to working with high voltage, because you are on a very scary path.
A Van de Graaff Generator IS IN NO way comparable to the voltage/current used in a high voltage tube amplifier.
Not trying to rain on your parade, but we certainly don't want any DEATHS to come from this.
Ok, I probably know more about this than you and more about it than the guy who said just because he has 1100 volts that his amp is dangerous. It depends on the CURRENT, not the voltage to make something dangerous. I don't need to be lectured on this, I already have a Physics degree from a top 20 university. PULLLEASE
I'm getting a little annoyed that the responses at this point. I'm getting mostly high school level science classes from people who've not done what I'm trying to do trying to tell me how to do it.
I don't need some newbie to start talking about the differences between toroidal and different OT designs... I don't need to know that electricity can be dangerous. I don't need to be talked out of what I want. I built my first amp kit in 4th grade, have a Physics degree from a top 20 university, I'm the CEO of more than one scientific company, I helped record my first album at age 10 or 11, I've been playing with the big toys since I was a kid. I just wanted to know if anyone has built a worthwhile tube amp yet and I don't see anyone who has done it DIY... maybe a little SE amp with 10 watts, but that's not going to do it for me. I'm looking to build the real deal. I know I can just buy an existing CJ or MCXXX amp and refurbish it and whatever. Only an idiot would not know this. I'm pretty sure there are no idiots with Physics degrees. And I worked in a lab that dealt with 150MW lasers and capacitors that put out 32kA. I think I'm covered on all the stupid replies about being killed by a 10 watt tube amp. Do you guys actually read the stuff you write? I've been trying to be nice, but this has been just a dorkfest of people who know nothing pretending to know something. Don't get me wrong because some have said some smart things, but nothing I can't find in Google in 30 seconds and nothing I didn't already know in 1993.
Normal operating current for this amp is up to 100 mA per tube. There are two tubes for 200 mA. That's enough to make you very dead.....The power supply is capable of a lot more than 200 ma when loaded by something abnormal......say a careless or clueless human, probably capable of 1/2 amp or more until one of the 5AR4's give out, but the power transformer is conservatively rated for half a kilowatt......That's enough to cook your flesh to somewhere beyond extra crispy after you are dead. Almost ANY tube amp beyond a few watts of power has enough "amperage" to kill you, AND enough voltage to force the current through you. Take this stuff seriously please!
There is a whole bunch of real electrical safety info on my web site but I doubt you will actually read it.
Electrical Safety | Tubelab
They made the transformers for Magz 200 watt per channel 833A amp. They WORKED right the first time. I paid $200 plus shipping for an experienced winder with a history of making good tube amp OPT's to make me a similar transformer that fell shore of expectations.....you want cheap? You aren't going to get a good clone of a Mac transformer. You want perfection, it ain't cheap!
Look it up, as I did.....it does not have the required cathode windings.
I have spent too much of my time looking stuff up and trying to help just to hear why it isn't right or what you want, I have some amps to build....I'm done here, good luck.
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