# Is Old Iron really better than new iron?



## Lincoln (Jun 2, 2008)

Is it worth chasing down old transformers from the 40's, 50's, 60's ? I've heard so many people say, "you can't get this kind of tone from a modern transformer!". ????

Voltage & amperage being equal.......is there something in the wire or construction or age of an old transformer that gives it magic tone?? 
I can see the old iron being better built, more reliable maybe.......but?

or is it that they were over-built and provided more headroom? Or did they sag more contribute to the super creamy/yummy distortion? But sag is more of a rectifier tube thing
isn't it? I'm confused


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## WCGill (Mar 27, 2009)

It's all in the steel and wire, the older being of better quality because it wasn't built to a price-point. Just as the secrets of manufacturing superior tubes has slipped slowly away from modern society, likewise with transformers. That being said however, it's much easier to reproduce replicas of older transformers than tubes. There are companies that possess the expertise to do it and are doing so now. So all is not lost.


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## Steadfastly (Nov 14, 2008)

No. Transformers transfer electricity. As WCGill says, some of the older ones were simply better built. It has nothing to do with sound or tone.


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## jb welder (Sep 14, 2010)

Agree with above (although some may argue about the quality of recycled metals).
Some older amps used big transformers that were overkill. So your point of them being overbuilt is valid. 
However, there are also many old amps that were built with under spec'd transformers, which may have contributed to their tone, but were prone to failure.
"It sounded so great... right before the smoke started coming out". In these cases, it is not that the transformer itself has "tone", but rather that it is stressed beyond it's limits.
So the "old-iron" thing can be a bit of a double edged sword.


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## mhammer (Nov 30, 2007)

Who was it that recently measured and noted surprisingly better performance from a _rusted_ output transformer? I'm serious. It was one of the transformer or boutique amp companies. I forget which. Not that rust made all the difference in the world, or that you should leave your transformers out in the rain to "improve" them. But the unit was a little rusted with age, and the rust did not impair performance. Whether the rust was _responsible_ for the performance is a whole other thing, but the writer speculated that it did play a role..


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## Were We Brave? (Oct 29, 2009)

mhammer said:


> Who was it that recently measured and noted surprisingly better performance from a _rusted_ output transformer? I'm serious. It was one of the transformer or boutique amp companies. I forget which. Not that rust made all the difference in the world, or that you should leave your transformers out in the rain to "improve" them. But the unit was a little rusted with age, and the rust did not impair performance. Whether the rust was _responsible_ for the performance is a whole other thing, but the writer speculated that it did play a role..


It was Mercury Magnetics. Here's the article in question:

http://www.mercurymagnetics.com/pages/news/VGmag/VGAug09Hamernik.pdf


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## WCGill (Mar 27, 2009)

Not sure what to make of that little test, especially since it was a power transformer. I buy a lot of MM iron because of the way it sounds, as well as variety amongst the different model lines. I don't really rust them that much, although it might be a marketing strategy, like pre-washed jeans or relic'd guitars.


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## dcole (Oct 8, 2008)

Bull cocky. I bet I could hook 2 transformers up to some power meters and make them say different numbers as well.


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## Lincoln (Jun 2, 2008)

dcole said:


> Bull cocky. I bet I could hook 2 transformers up to some power meters and make them say different numbers as well.


I kind of agree with that. Good article but I really have to question why they did it or what they hoped to prove? Was the MM warehouse under water recently or something?


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## StevieMac (Mar 4, 2006)

dcole said:


> Bull cocky. I bet I could hook 2 transformers up to some power meters and make them say different numbers as well.


Although he indicates both trannys were "drawing the same power" when new, the differences shown in the readings seem basically negligable to me i.e. around 5% on average.


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## Wild Bill (May 3, 2006)

I agree whole heartedly that SOME older OTs sounded better!

An output transformer is NOT a power transformer! A power transformer handles only one frequency, 60 hz. That's the frequency of the voltage from the wall. An output trannie handles the entire frequency range of a guitar or other instrument, or in the case of a PA amplifier it handles the entire audio spectrum.

Over such a wide frequency range there are a lot of variables introduced by the materials and by how the transformer was actually wound. Many OTs in the old days were "scramble wound" as opposed to the nice, regular layers of windings we see from modern manufacturers. This can make a BIG difference in the overall response, also making it non-linear, or different at different parts of the spectrum.

Now because tone is a personal choice, sometimes the variables in the build of an old OT hurt what most would consider good tone and sometimes it beefed it up! Again, it is all really a matter of choice.

I've seen well-researched articles claiming an OT can account for as much as 30% of a guitar amp's tone. I think those claims are exaggerated a little bit, since they always seem to compare between an OT with a good reputation and one that is really a piece of crap! A more fair comparison would be between one of the best and one of the usual ones available for us to buy for our builds. Still, they have proven that there is SOME worthwhile difference, at least to me!

If those old JMP Marshalls had used modern Chinese made OTs we would have grown up taking that tone for being "normal"! That's not what happened, of course. We spent our formative years listening to amps built with those old Drake and Partridge OTs and they gave the sound we learned to love so well.

MM and a few others spent a lot of time and effort reverse engineering those OTs from the Golden Years and have done a great job replicating them. 

As a point of interest, some modern Marshalls may contain OTs marked "Drake". Unfortunately, the real Drake factory has been a parking lot for years now. Marshall's lawyers now own the name so they can let some modern factory use it under license. Whether or not they are actually building OTs identical to the Drakes of yore is a moot point but so far the consensus seems to be that they are not the same. The same situation has happened with the speaker name of Jensen. Fender has them made by some company in Italy and legally may put the Jensen name on them.

Anyhow, part of a guitar amp's tone may come from having an OT that is not very "hifi" in quality. Trannies are expensive and skimping on the amount of copper wire or the quality of the iron/steel laminations can offer a significant price saving. This makes them a poor choice for a tube power amp for listening to your vinyl LP collection but for a guitar that after all, is SUPPOSED to have some distortion it can often offer a better tone to a musician's ear, depending on what sort of music he prefers to play. 

This is why Hammond OTs were not that popular in guitar amp builds over the years. They were too good! Fabulous in that homemade power amp for your stereo hifi setup but a bit too "sterile" and overly clean in a guitar amp application. Many techs learned that the solution was to overdrive the hell outta them! If you were building a 50 watt guitar amp you would use a Hammond OT rated for only 30 watts or maybe even 25!

This made them sound great! Since Hammond also makes over-rated quality product there were no worries about burning the OT out. Hammond builds TOUGH trannies!

Now, Hammond decided to offer replacements for the classic Fender, Marshall, Vox and Traynor amps. Their engineers understood that a guitar amp was a different application and took all the necessary parameters into account. I have used some of them and I like them very much!

So that's just my humble opinion but as usual, I think there is some good science behind it. However, in the final analysis, if it's your amp then it's your ears that must be happy!

Wild Bill/Busen Amps


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## mhammer (Nov 30, 2007)

I was reading in Vintage Guitar about the old Fender 5F10 Harvard amplifier. It used a pair of 6V6 tubes in push-pull mode, but was rated at around 10-12W, chiefly because it provided a noticeably lower plate voltage than one typically sees when a dual-6V6 amp is rated at around 20W+.

If you look over enough tube amp schematics, you'll often find that the difference between model X and model Y can be as simple as the plate voltage supplied to the power tubes. This model puts 360V on a pair of gV6s and that model puts 380V on them. People will talk about the two amps as if they are very different, but under the hood, we are sometimes talking about the way that a different supply voltage changes the tone of the tubes. So if the rusty power transformer, or if what is simply an "older" transformer, provides slightly more juice to the tubes, it may well sound a little different, and possibly better to some ears.


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## nonreverb (Sep 19, 2006)

Primary winding asymmetry also contributes to the tone of the output. I've seen some output trannies with 10% or higher static resistance on one side as compared to the other. This translates into a slightly unbalanced output which in can often sound great in a guitar amp.


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## Wild Bill (May 3, 2006)

nonreverb said:


> Primary winding asymmetry also contributes to the tone of the output. I've seen some output trannies with 10% or higher static resistance on one side as compared to the other. This translates into a slightly unbalanced output which in can often sound great in a guitar amp.


Unbalanced? Well, it is and it isn't, NR!

There is almost always a DC resistance difference of the winding on one side compared to the other, in an output transformer. That is because the windings are wound on top of one another. This means one coil is wound with a smaller cross-section, and with fewer turns of wire to achieve the necessary inductance to do its job. Only if the two windings were wound side by side would you expect them to be equal.

Again, an output transformer is NOT a power transformer! It is an IMPEDANCE transformer that must work across a desired range of frequencies! To achieve those ends and be balanced in frequency response in both windings of a pushpull output transformer you have to have physical differences between the windings, since one winding is wound over and on top of the other.

Some OTs from the Golden Years didn't worry about that as much as perhaps they should. This made big differences in tone. No one has yet talked about saturation, when we are really pumping power through an OT! That alone will make a big change in tone!

It seemed to have been pure luck in the early days that had an OT give a better guitar tone than another. Especially since there was little actual design research happening. All the research had to do with building a better hifi transformer. For guitar amp use, the manufacturer would just start cutting corners,trying to give an acceptable product at a lower price than his competitors.

Wild Bill/Busen Amps


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## nonreverb (Sep 19, 2006)

True Bill, But as stated earlier added to the fact that many old transformers were scramble wound and you get the picture plus I have seen examples where there are definitely significant differences in resistance that can't be explained by wind layering. Their just sloppy made transformers that happen to sound good. There are plenty out there that don't sound too good as well.


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## Wild Bill (May 3, 2006)

nonreverb said:


> True Bill, But as stated earlier added to the fact that many old transformers were scramble wound and you get the picture plus I have seen examples where there are definitely significant differences in resistance that can't be explained by wind layering. Their just sloppy made transformers that happen to sound good. There are plenty out there that don't sound too good as well.


No argument here, NR!

However, I still can't understand why no matter whether its a trannie involved or something else, the amps that come into my shop always sound better when the customer is playing them!

I really should study the acoustics in this place!

Wild Bill/Busen Amps


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## Milkman (Feb 2, 2006)

Wild Bill said:


> No argument here, NR!
> 
> However, I still can't understand why no matter whether its a trannie involved or something else, the amps that come into my shop always sound better when the customer is playing them!
> 
> ...


Fred is the best judge I think.

He seems to have a good ear.


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## nonreverb (Sep 19, 2006)

I dunno Bill, you kinda have the best job as you get to hear them all :food-smiley-004:



Wild Bill said:


> No argument here, NR!
> 
> However, I still can't understand why no matter whether its a trannie involved or something else, the amps that come into my shop always sound better when the customer is playing them!
> 
> ...


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## Lincoln (Jun 2, 2008)

Wild Bill said:


> All the research had to do with building a better hifi transformer. For guitar amp use, the manufacturer would just start cutting corners,trying to give an acceptable product at a lower price than his competitors.
> 
> Wild Bill/Busen Amps


How about organs? (the kind with white & black keys) Are the output transformers used in old Hammond organs (2x 6V6) any better than guitar amp OT's were? Were they any better quality or built to closer tolerances maybe? 

The reason I ask is I scored a pair of old Hammond amps that I planned to use (the parts from) for a 5E3 and a Princeton Reverb build. You've got me wondering if I should be buying the best new OT money can buy instead.


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## nonreverb (Sep 19, 2006)

Hey Lincoln,

Are they AO-44's or AO-35 amps?? Actually, any of the EL84 type power anp output trannies are excellent for makin' amps. Hammond made all of their own tramsformers for most of the tonewheel production era. Very high quality for the time and sound great. Only thing is they're almost all single 8 ohm secondary. I've used the outputs as subs in both Blues JR's and 6V6 amps with great results. The power trannys can handle plenty as well. Most have a 5V for 5U4. A few are 5Y3's.


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## Lincoln (Jun 2, 2008)

nonreverb said:


> Hey Lincoln,
> 
> Are they AO-44's or AO-35 amps?? Actually, any of the EL84 type power anp output trannies are excellent for makin' amps. Hammond made all of their own tramsformers for most of the tonewheel production era. Very high quality for the time and sound great. Only thing is they're almost all single 8 ohm secondary. I've used the outputs as subs in both Blues JR's and 6V6 amps with great results. The power trannys can handle plenty as well. Most have a 5V for 5U4. A few are 5Y3's.


One is an AO-29 and the other is a AO-20880. They are a little older than the hammond amps that used EL84's. Both of these have a 5Y3 or 5U4 and two 6V6, three little 7 pin tubes (6AU6?) and four 12AX7 types. Huge PT's, nice sized OT's and 2 smaller transformers, (probably a reverb driver and a choke). They are out of Hammond M100 organs. ( I think)
I can live with 8 ohms 

Edit:
nonreverb, I just noticed your sig & see you're big into hammond! That's pretty cool. Can you tell me what style of reverb tank I need to find to match the reverb driver in these amps?


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## nonreverb (Sep 19, 2006)

Yes, they use a high impedance tank. I'm assuming you didn't get the accompanying tanks with the amps?
Just for interest sake, did you know that Laurens Hammond who invented the mighty Hammond Organ also invented the reverb tank?


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## Lincoln (Jun 2, 2008)

nonreverb said:


> Yes, they use a high impedance tank. I'm assuming you didn't get the accompanying tanks with the amps?
> Just for interest sake, did you know that Laurens Hammond who invented the mighty Hammond Organ also invented the reverb tank?


no, I didn't get the tanks. Have you got any extra tanks to sell me? I'm looking for 2 of them. 
and Yes, I learned who invented reverb while researching these amps before I bought them. The internet is a wonderfull thing at times.


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## nonreverb (Sep 19, 2006)

Let me cross reference those amp numbers. I have a stack of Hammond reverb tanks. I'm sure I have a couple that will do.


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## Lincoln (Jun 2, 2008)

nonreverb said:


> Let me cross reference those amp numbers. I have a stack of Hammond reverb tanks. I'm sure I have a couple that will do.


I had a better look, only one amp has reverb so I'm only looking for one Hammond reverb tank. The AO-20880 amp is older. It uses 6SC7's and 6SJ7's for everything except power tubes and rectifier, but the PT looks like something Pete Traynor would use 

View attachment 2958


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## nonreverb (Sep 19, 2006)

This is out of a Hammond M2 organ made between '49 and '54. It's missing the dog house (volume control air capacitor) but looks pretty well complete other than that. The AO-29 is the later version. It could be out of either an M100 series or M3. Neither of these have reverb.



Lincoln said:


> I had a better look, only one amp has reverb so I'm only looking for one Hammond reverb tank. The AO-20880 amp is older. It uses 6SC7's and 6SJ7's for everything except power tubes and rectifier, but the PT looks like something Pete Traynor would use
> 
> View attachment 2958


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## Lincoln (Jun 2, 2008)

nonreverb said:


> This is out of a Hammond M2 organ made between '49 and '54. It's missing the dog house (volume control air capacitor) but looks pretty well complete other than that. The AO-29 is the later version. It could be out of either an M100 series or M3. Neither of these have reverb.


Oh well. Reverb drivers are cheap, I'm not broken up about it for sure. 49 to 54 huh? That explains the age of things. Resistors look like the ID stripes were hand painted with a brush and the caps are wax & cardboard. Aerovox Canada LTD

The other amp is much newer. things are dated about 1967 is that's possible. Good, clean, fun


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## nonreverb (Sep 19, 2006)

Yes, M100 was made to '68. Does it have a fuse holder? If it does, it's a Canadian one.


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## Lincoln (Jun 2, 2008)

nonreverb said:


> Yes, M100 was made to '68. Does it have a fuse holder? If it does, it's a Canadian one.


Like an amp fuse holder? No it doesn't.

View attachment 2961


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## Lincoln (Jun 2, 2008)

Here's a picture of those 3 coils I thought might be reverb related.

View attachment 2962


They are on the pre-amp end not the power supply end so I didn't think they were chokes.


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## nonreverb (Sep 19, 2006)

These three are for the percussion circuit. The one in between the can caps is the output.


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