Does expensive output transformer sounds better?

[The Dude]

it was a bit long so I didn't read it right through. Did he say, I'm marvellous, China is shit?

I have been laughing at this one all day.

[Enzo]

SGM has repeatedly shown us that he will take a sample of one and consider it systematic. If we are discussing an amp, and tell some poster that such and such a cap is not making the noise in his amp, SGM feels free in his mind to decide we think that sort of cap never makes noise. The unwarranted extrapolation. As we follow the genesis of the Crate enmity, he once told of an amp they couldn;t fix so they "sent it to Crate", and when it returned ti still wasn;t right. So therefore, in his mind, ALL Crates are unrepairable. And that is ignoring for the moment the very notion of having to send a basic Crate solid state amp out for repair in the first place.

[Alan0354]

Ha ha, how do we get here!!!! Don't mind me, keep going.

he he, I use Chinese cap, and ceramic cap if all possible. I am still working on the sound. But noise......No!!!! I removed the input grid stop and change to DC filament for the first few tubes ( not regulated, only bridge rect and cap). The noise is so low, particular the hissing sound ( white thermal noise) is so low. I can still here the 120Hz a little when I crank the high gain channel up, but it is nothing. I have to try regulated DC for the first tube to see whether I can improve it or not. But it is NOT A PROBLEM with the Chinese caps.......or the Chinese resistors ( order all my resistor from Hong Kong and China). It is my mission to prove those orange drop, carbon comp are snake oil. I don't use silver mica, they are too expensive, I am born cheap, this is against my believe.

[soundguruman]

Ha ha, how do we get here!!!! Don't mind me, keep going.

he he, I use Chinese cap, and ceramic cap if all possible. I am still working on the sound. But noise......No!!!! I removed the input grid stop and change to DC filament for the first few tubes ( not regulated, only bridge rect and cap). The noise is so low, particular the hissing sound ( white thermal noise) is so low. I can still here the 120Hz a little when I crank the high gain channel up, but it is nothing. I have to try regulated DC for the first tube to see whether I can improve it or not. But it is NOT A PROBLEM with the Chinese caps.......or the Chinese resistors ( order all my resistor from Hong Kong and China). It is my mission to prove those orange drop, carbon comp are snake oil. I don't use silver mica, they are too expensive, I am born cheap, this is against my believe.

try wait, the circuit board can be damaged and it is best to have a pro technician install the modifications.
so consider not doing it yourself, but rather, let an experienced person work on it.

This is the 4100 mod
marshall jcm 900 pre.pdf

I apologize if that does not attach correctly

1. R35 is 10K. Replace R35 w/ 68K - prevents the input from overloading, distorting. Takes some grit out...I use 1/2W metal film, but it's your party.
2. C 8 is 470pf. Change C8 to 100 pf. -- C7 is 22 pf. Change C7 to 100 pf. The hi upper mid is a bit harsh and this is mellowing it out a bit. I use silver mica, but it's your choice...
3. C25 is .047 uF. Change C25 to .1 uF.I used a big honk'en Mylar cause it sounded cool. This gives the clean channel a bit more bottom end.
Yeah, this amp just has too harsh a high frequency, so this helps balance it out a little more.
4. Bypass R54 with a 500pf capacitor. I used silver mica. this is helping to find a less muddy tone for the clean channel. Helped the definition and made the highs more sparkly and less harsh.
5. Remove LEDs 1-4. This stops the clean channel from clipping, and it's completely clean, like a twin reverb...no longer breaks up in the clean channel...
6. C34 is .001 uF. Change C34 to 250 pf. It's kinda like the bright switch for the clean channel, but not too bright. I used silver mica. Again more sparkly in the high end...
7. Take out C33. This is intended to kill noise in the clean channel, but it's too muddy. And the clean channel doesn't need it anyway.
8. Bypass R2 with a 6.8 uF 25 Volt or higher volt electrolytic capacitor. The + of the cap will face the cathode of V1A.
Basically, there is a mistake in the design which kills the bass response of the amp. This is going to allow V1A to pass low frequencies. Suddenly the amp is going to sound like a Marshall, when before, it did not. Again, this resolves the high frequency harshness of the amp. The Lows will be balanced, much better with the highs.

Now I am going to change the overdrive EQ and gain. This makes the amp sound quite a bit sweeter, more like an Old Marshall.


9a. R43 is 4.7K. Change R43 to 10K
9b. R7 is 4.7K. Change R7 to 6.8K.
9c. R37 is 22K. Change R37 to 10K.
9d. R38 is 10K. replace R38 with a wire jumper.

Now we are up to the tonestack...

10. R13 is 220K. Remove R13 and leave it out. This resistor makes the amp too polite. Removing R13 makes the amp more aggressive. And, 13 is an unlucky number anyhow.

11. Remove C11 and replace it with a wire jumper. The voltage on the input of the tone stack is now about 110-132 volts DC.

12a. Replace C37 with a 470 pf 500 Volt silver mica Capacitor.
12b. Replace C 38 with a .022 uF 600 Volt Orange Drop Capacitor
12c. Replace C39 with a .022 uF 600 Volt Orange Drop Capacitor

Well, you don't have to use silver mica and orange drops, but I liked the way it sounded.
You can use what you like...
The 3 capacitors, C37, C38, C39, should be at least 250 Volts or higher.

13. We skip 13 cause it's unlucky.

14. Now, because we made the clean channel cleaner, we are going to increase the sensitivity of the Clean Master Volume...
14a. Pin 2 of IC8 goes to ground. Cut that track, right in the middle...
14b. Install a 1 meg resistor between pin 2 of IC8 and ground.
Now, the settings of clean master volume and overdrive master volume will be "closer" together. There will not be such an extreame
difference between them...

15. Reverb Wires:
15a. The reverb send and return wires are located very close to the input jack.
15b. Reverse the location of the send and return wires, where these go thru the chassis holes, to the reverb tank.
15c. Move the location of the reverb wires, away from the input jack. Relocate the route of these wires, so they
are as far away from the input jack, as possible. Route these wires around the inside edge of the chassis, so they are no longer
parallel with the input jack. Make the separation distance, from the input jack, as wide as possible.

There will be a whistling oscillation in this amp, because the reverb wires are too close, to the input jack.
Move those wires away, from the input jack, to stop the oscillations.

You can see how I moved those reverb wires, away from the input jack.
This is necessary, to stop an oscillation loop, between the input and the reverb circuit.

Now there is one remaining issue:
The effects loop
The effects loop levels in this amp are incorrect, and will not work with a standard USA effects pedal.
The effects loop must be modified to work correctly.

[soundmasterg]

Alan,

Just to give you my experience with transformers....

A customer had an original power transformer fail in a Magnatone 260. No one had an exact clone except MM. No one could unwind and rewind his that I knew of except MM. The rewind was too expensive, so the customer went with the MM reproduction, which was also expensive, but not as bad. The amp works again and sounds as good as it did before. It doesn't sound better however, but this was the best solution for this application.

I had Heyboer make me a Vox AC100 clone OT and choke for a project and they are reasonably priced and the transformer and choke are fantastic. Thats not to say that a MM clone wouldn't sound good either, but the Heyboer was a lot cheaper. I have used some Weber transformers and they are good quality and sound good. I remember when Ted was getting them developed and recall the conversations he had with people on his forum about what kind of things to look for. It took awhile but he got transformers made that are often better quality than many of the name brands for much less money. I don't know how close his trannies are to vintage spec however.

The quality of sound and the frequency response of an OT depends a lot on the type of metal used in the transformer. M6 will be higher quality than M17 for example. Interleaving also matters. Fender's tweed Triad transformers were better quality than their Schumacher stuff, partly because of the interleaving, and also because of higher metal quality, but Leo probably figured the Schumacher stuff was good enough and a lot of BF and SF Fender users seem happy with their amps.

My amp build that started life as a Bogen before I gutted it doesn't use the greatest quality transformers, and they are undersized too for the power of the amp, but the amp sounds great. So you can make a good sounding amp with lousy transformers but it is much easier when you use good transformers.

Greg

[soundguruman]

Alan,

Just to give you my experience with transformers....

A customer had an original power transformer fail in a Magnatone 260. No one had an exact clone except MM. No one could unwind and rewind his that I knew of except MM. The rewind was too expensive, so the customer went with the MM reproduction, which was also expensive, but not as bad. The amp works again and sounds as good as it did before. It doesn't sound better however, but this was the best solution for this application.

I had Heyboer make me a Vox AC100 clone OT and choke for a project and they are reasonably priced and the transformer and choke are fantastic. Thats not to say that a MM clone wouldn't sound good either, but the Heyboer was a lot cheaper. I have used some Weber transformers and they are good quality and sound good. I remember when Ted was getting them developed and recall the conversations he had with people on his forum about what kind of things to look for. It took awhile but he got transformers made that are often better quality than many of the name brands for much less money. I don't know how close his trannies are to vintage spec however.

The quality of sound and the frequency response of an OT depends a lot on the type of metal used in the transformer. M6 will be higher quality than M17 for example. Interleaving also matters. Fender's tweed Triad transformers were better quality than their Schumacher stuff, partly because of the interleaving, and also because of higher metal quality, but Leo probably figured the Schumacher stuff was good enough and a lot of BF and SF Fender users seem happy with their amps.

My amp build that started life as a Bogen before I gutted it doesn't use the greatest quality transformers, and they are undersized too for the power of the amp, but the amp sounds great. So you can make a good sounding amp with lousy transformers but it is much easier when you use good transformers.

Greg

Yeah I think people put too much emphasis on the transformer,
and not enough on the circuit design.
And they say that "this" transformer blows up all the time...
but I think more likely abused, and blows it up, from wrong impedance..etc...

But I have no problem with it, at all.

[Guitarist]

What about toroids? They seem the shizzle for PT but for OT rarely used at all. They'd also be great for the negating proximity-pickup hum—efficient too.

[tedmich]

Antek used to make these, and primrose Audio and Plitron / Amplimo currently build and sell toroidal OTs and they are advocated by HiFi guru Menno Van Der Veen Modern High-end Valve Amplifiers: Based on Toroidal Output Transformers: I.R.Menno Van Der Veen: 9780905705637: Amazon.com: Books
but they are dismissed out of hand by many audiophiles as inferior to C core types.

Plitrons humongous 25lb PAT-4141-00 has to get a mention for its 400w 6550 design!
http://shop.plitron.com/specs/414100.pdf
only CAN$483.69


less of a bargain C-core single ended OTs with silver windings and exotic AN Super Perma Ni cores can be bought for only $16k at the HiFi collective, and people love their Lundahl C cores too

[Leo_Gnardo]

What about toroids? They seem the shizzle for PT but for OT rarely used at all. They'd also be great for the negating proximity-pickup hum—efficient too.

One of the hobby mags (Glass Audio?) had an article in the 90's, an amp built with toroid PT and OT, IIRC Plitron parts. All good up to clipping, where the signal does very unexpected things. Suffice it to say, I've avoided toroid OT's since and notice everyone else has too.

[tedmich]

One of the hobby mags (Glass Audio?) had an article in the 90's, an amp built with toroid PT and OT, IIRC Plitron parts. All good up to clipping, where the signal does very unexpected things. Suffice it to say, I've avoided toroid OT's since and notice everyone else has too.

Happy 1k Leo!

[bob p]

Getting back to the OP's question about MM vs other transformers:

I really wish he would search the archives for this information. There is lots of information here that puts the history of MM into it's proper context.

Once upon a time, they were a small transformer company in California that didn't have the well known reputation that they have today. That is to say, the techs knew who they were, but they were not a known name among end-user musicians. MM had a smaller line of reproduction transformers that were designed as drop-in replacements for transformers from classic amps that were otherwise hard to find. They were a very helpful group of people, who would destructively reverse engineer a unique transformer at your request, provided that you were willing to pay for their time to do it. It was expensive, but it was one of the only ways to get the right transformer if it was hard to find for your application. Once they did a revese engineering job they'd begin to sell reproductions of that recipe, and they gradually expanded the size of their catalog of "cloned" iron.

Once upon a time, MM was an inexpensive transformer. That is to say, I was able to buy a dozen units at a time, and get a custom "tone clone" MM transformer for less than the cost of an equivalent generic Hammond. Back in the day I opened a dealership account with MM and coordinated a few group buys on this site so that everyone could get a good deal on a decent transformer. I don't remember the exact number, but if memory serves me correctly I've bought well more than 50, but probably less than 100 of their products.

Initially, all of the orders were filled with first quality product. On my first order I liked what I received, so I ordered more on my second order. On my second order I liked what I received, so I ordered more on my third order. On what I seem to remember was the third group buy, I put together a much larger order for perhaps 30+ units. On that order I ended up receiving some not so good quality product. I thought that some of the transformers were obviously seconds. Some of the defects in the merchandise included cut and spliced wires with shrink tubing on them, torn paper insulation, poorly executed spray on coatings, and teflon wires that were protruding through their insulation. Overall, the quality of the workmanship of the pieces in the 3rd order seemed vastly inferior to what I hard received in the 1st and 2nd orders.

When I complained about the poor quality MM was kind enough to offer exchanges if I absorbed the cost of return freight, which I thought was their responsibility for having shipped what I deemed to be reject-quality factory seconds. I honestly think that they filled my first couple of orders with good quality merchandise to build my confidence in them, and then once I swallowed the bait I think that they filled my subsequent order with undesirable factory seconds that they were trying to get rid of, just to dump their undesirable inventory on me. Because of their inconsistent quality most of the people who were in on the group buy didn't want to accept the iron, and I was left stuck with a large box of $100 doorstops. Because of the high cost of return freight to California, I was going to lose money trying to exchange the iron, and I didn't have confidence that what they were going to ship me in return would make the exchange worth the cost. I was trapped in a lose-lose situation, and I ended up cutting my losses by selling the iron at a loss just to get rid of it. I never put together another group order because I didn't trust them after I got burned.

It was sometime around then or shortly after that that MM started to gain a reputation on the builders' boards about good quality. Unlike my situation, where I bought at wholesale in volume and received what I thought was crap, it seemed that there were a lot of people who were buying in 1-unit quantities at retail who were getting good product and were satisfied. MM responded to the spread of the good word at the retail level with an aggressive marketing campaign to make their name known among end users. Once their name became known by end users they responded with price increases.

I think that MM iron is now ridiculously expensive for what it is. Their pricing demands too much of a premium, in my opinion. Today even with my dealer's end-column discount, the MM iron costs far more than I think is reasonable.

Back when their dealer prices were below the cost of buying from other sources, buying MM iron was a tempting proposition. But factoring in the problems related to the receipt of what I thought were poor quality specimens on my wholesale account, I quickly lost interest in doing more business with them. Now that their prices are so high, I can't see any reason to buy anything from them. IMO their name isn't worth the price premium that they're trying to attach to it. I'd only buy from them if I desperately needed something that wasn't available elsewhere.

Regarding that original question about their DR OT: I used their BF DR OT in one of my builds. I'm very happy with it. But if I were doing it all over again I'd probably just buy something from Hammond or ClassicTone.

[Joe L]

My friend and I built matching DRs. He used the ClassicTone and I used the Heyboer DR replacement from Mojo. The amps sounded identical until they were dimed. Mine distorted musically and his had an obvious buzzy distortion. I later built a Marshall 18 watter with a ClassicTone and it was horribly buzzy. I ordered a new transformer from GDS made by Heyboer and at every gain level, the amp sounded better. It wasn't subtle. Even squeeky clean, you could strum a chord and it was so rich and musical.

Since then, I have only used Heyboers and have been very happy.

BTW, an observation on the side topic above... Read about the Dunning Kruger Effect here.

[bob p]

Dunning-Kruger? Weren't those the Ivy-League psychologists who said that you have to be smart to know that you're dumb? That kind of wisdom only comes from the Ivy League's finest...

It's interesting that you didn't like the Classictone product. I haven't tried them, but I wouldn't be afraid to do so based upon the good rep that they enjoy around here.

[Joe L]

It's interesting that you didn't like the Classictone product. I haven't tried them, but I wouldn't be afraid to do so based upon the good rep that they enjoy around here.

Hehe... Wanna buy an 18 Watt transformer cheap?

[bob p]

I've got my bases covered, thanks. (I still have plenty of cosmetic seconds that woud only appeal to a guy like me who doesn't care as much as the retail guys about what a transformer is supposed to look like.)

Regarding that comment about illusory cognitive superiority -- it looks like they've found the anatomic cause -- dysfunction of the orbitalfrontal and anterior cingulate cortices:

Neural systems of social comparison and the ?above-average? effect

http://www.sciencedirect.com/science...53811912002832