Tweed Deluxe Output Transformer Upgrade Experience

jsnwhite619

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Well, what is it?

Looks like for 5E3 OT, the typical is 8K primary but the PAM-OT-20-16R uses a 12K primary. Not sure what the perceived net audio effect would be from this deviation, but they are presumably wound to a different spec than other 5E3 OT's.
I'm going to guess a substantial difference. I think that's the highest spec I've ever seen offered for a PP amp. A 12k primary is probably going to have a lot less headroom and output, but that's just my guess. I've only mostly experimented with primaries in the same amp on 5f2a Princeton SE builds - trying 5k & 8k on the same amp and swapping back & forth, and it can be a very big difference in headroom. I built a Harvard with a 6.6k 20W Deluxe Reverb OT once and that thing was the loudest one I've built and just would not breakup with single coils. The normal 8k Princeton Reverb OT I normally use is an entirely different story - gets nice and saturated.

This calculator has a 10% safety net factored in and figures for maxed out use I think, but it's fun to use and plug in numbers and see what changes. In this case of 8k vs 12k for a Tweed Deluxe (I used a 350v PT here) we get a current draw of

**122mA for 8k primary
** 86mA for 12k primary

So, if you wanted to build a scaled down 5E3 and use a Champ PT to do it, a 12k would probably be perfect.


And for comparison, 145mA for a 6.6k Deluxe Reverb OT.
 

gabasa

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So, if you wanted to build a scaled down 5E3 and use a Champ PT to do it, a 12k would probably be perfect.
This is why this conversation is so interesting to me. Based on the numbers, your statement makes sense. However, only our ears can make tonal decisions, and to say that this OT is good for a "scaled down" 5E3 is, at best, partially correct.

This is an amazing OT for any 5E3 build, and a sonic upgrade from the ones we're used to using from the larger, better known companies. Anyone that shies away from it based on the primary impedance spec is losing out. It's freaking fantastic!

George Alessandro cherry-picked the best sounding 5E3 he could get his hands on, for PAM to reverse engineer. Is that not good enough? Even so, I was still scared to pull the trigger on this purchase because of the 12k spec, but now I'm so glad I did.
 

printer2

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Threw in 12k into Universal Loadline Calculator and with a 6V6 at 350V, looks ok to me. I would think 10k a better fit for maximum wattage but three watt difference probably be unnoticed.
 

sds1

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and to say that this OT is good for a "scaled down" 5E3 is, at best, partially correct.
He said PT, not OT. Maybe pushing it as a matter of taste (hence why said scaled down), but the 5F1 PT's provide 100mA so this is pretty close to what is needed when the power tubes are only drawing 86mA max.

However, only our ears can make tonal decisions
I still believe your conclusions based on the numbers (I don't see anything stated in conflict with your conclusions here?), with less current consumption the entire amp will operate in a more linear fashion when under load.

You could possibly achieve a similar satisfying result with a bigger PT.

The PT's and OT's of these amps are most definitely mojo because they were mostly specced to be "in the way", obviously size weight and cost of the iron being the driving factors there. Seems like the new OT moves the trannies out of the way a bit, I happen to believe that most players would appreciate such a change, especially on the really old circuits that were kinda red-lined in many ways.

I would think 10k a better fit for maximum wattage but three watt difference probably be unnoticed.
So this is a big part of the tradeoff, less current consumed for some loss of clean power transfer.

Would be interesting to measure this though, maybe you even get some of that power back via the PT's improved performance under load?
 
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printer2

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printer2 said:
I would think 10k a better fit for maximum wattage but three watt difference probably be unnoticed.
So this is a big part of the tradeoff, less current consumed for some loss of clean power transfer.

Would be interesting to measure this though, maybe you even get some of that power back via the PT's improved performance under load?

How would you get more of the power back? The software does not know what the PT is doing, it could even be a 'improved performance PT'. It looks at the load line impedance and the voltage swing determined by the supply voltage and the tube's parameters.
 

jsnwhite619

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Threw in 12k into Universal Loadline Calculator and with a 6V6 at 350V, looks ok to me. I would think 10k a better fit for maximum wattage but three watt difference probably be unnoticed.
Don't know how much difference it would make, but I was working off of 350v PT but what would be around 400v B+ probably. Most 5e3 PT's seem to be 350v-355v spec, and the only original I've been able to measure was 396v B+.
 

2L man

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Obviously no-one has not yet test Antekinc MP-10W80 toroidal OT which is only $44? I have built two PP and one SE around European toroid OTs although one did cost double and two more than double. Obviously because they are HiFi rated they have lots of spare performance for guitar rather limited frequency range and sound get lots of clarity?
 

sds1

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How would you get more of the power back?
You wouldn't get any of that transfer power back but rather possibly recover some of the amp's clean audio power by way of less distortion from the non-linearity of the PT under load. I didn't mean to conflate the 2 power measurements, although they are related...
 

jsnwhite619

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This is why this conversation is so interesting to me. Based on the numbers, your statement makes sense. However, only our ears can make tonal decisions, and to say that this OT is good for a "scaled down" 5E3 is, at best, partially correct.

This is an amazing OT for any 5E3 build, and a sonic upgrade from the ones we're used to using from the larger, better known companies. Anyone that shies away from it based on the primary impedance spec is losing out. It's freaking fantastic!

George Alessandro cherry-picked the best sounding 5E3 he could get his hands on, for PAM to reverse engineer. Is that not good enough? Even so, I was still scared to pull the trigger on this purchase because of the 12k spec, but now I'm so glad I did.

Definitely not trying to rain on your parade - if you like it, congratulations. I'm just saying that I would expect a 12k OT to reduce output and clean headroom vs an 8k and definitely from a 6.6k OT. And if the 12k OT limits the overall current draw for the amp, you could get by with a much smaller/lower spec PT.

If I've learned anything in the past several years of seriously getting into amps, it's that "best" is always relative. The most awful, flat-out worst sounding speaker I've ever heard in a Tweed Deluxe is a Celestion Blue - and most people think that particular $300 speaker is the "best" thing you can get for it. Kinda like the violinists who all want a Stradivarius to play, but end up preferring the sound of new, modern violins in a blind test. https://www.thestrad.com/blind-test...s-violins-from-modern-instruments/994.article

And the second thing I've learned is that I've seldom modded or changed anything in an amp that I didn't think was an improvement at first...then swapped back and liked the original better...then tried something else and thought I liked it better...and the viscous cycle never ends. I stopped relying solely on my ears and memory a long time ago, and now record and compare changes I make. Memory & 110+dB make it hard for me to get a direct comparison.

He said PT, not OT. Maybe pushing it as a matter of taste (hence why said scaled down), but the 5F1 PT's provide 100mA so this is pretty close to what is needed when the power tubes are only drawing 86mA max.
Only after Hammond started offering their 100mA 290AX & 115mA CAX did the Classictone and the others step-up their Champ/Princeton PT's (as far as I know). Everything used to be 70mA for Fender replacement - from 5f1 to Princeton Reverb, they all had 70mA power transformers, even the "upgrade" market. So, in that regard, a 70mA PT and a 12k OT would probably give a greater difference.
 

gabasa

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Did it cut the volume and bass compared to the one you swapped out?
The bass is much clearer and more natural sounding than what I'm used to, I always found the amp a bit tubby sounding and that's completely gone now.

A friend has an identical amp, other than a Classictone output transformer. He's going to come by one day soon and I'll do some more listening tests side-by-side, and an overall volume comparison.
 

gabasa

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Well yours apparently does, no?

How much of the awesomeness of your deluxe do you attribute to having a choke?
I built it with the choke, I always do. The Champ I played for years, which I recently sold, had a choke, and so does the Harvard that I built.

In side-by-side tests, the amp with the choke had more clarity, but the impedance of the choke is much lower than the resistor that's normally there, so the difference in sound may have been attributed to the difference in preamp or phase inverter voltages. I'm not sure about this, maybe someone can explain.
 

gabasa

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Definitely not trying to rain on your parade - if you like it, congratulations. I'm just saying that I would expect a 12k OT to reduce output and clean headroom vs an 8k and definitely from a 6.6k OT. And if the 12k OT limits the overall current draw for the amp, you could get by with a much smaller/lower spec PT.

If I've learned anything in the past several years of seriously getting into amps, it's that "best" is always relative. The most awful, flat-out worst sounding speaker I've ever heard in a Tweed Deluxe is a Celestion Blue - and most people think that particular $300 speaker is the "best" thing you can get for it. Kinda like the violinists who all want a Stradivarius to play, but end up preferring the sound of new, modern violins in a blind test. https://www.thestrad.com/blind-test...s-violins-from-modern-instruments/994.article

And the second thing I've learned is that I've seldom modded or changed anything in an amp that I didn't think was an improvement at first...then swapped back and liked the original better...then tried something else and thought I liked it better...and the viscous cycle never ends. I stopped relying solely on my ears and memory a long time ago, and now record and compare changes I make. Memory & 110+dB make it hard for me to get a direct comparison.


Only after Hammond started offering their 100mA 290AX & 115mA CAX did the Classictone and the others step-up their Champ/Princeton PT's (as far as I know). Everything used to be 70mA for Fender replacement - from 5f1 to Princeton Reverb, they all had 70mA power transformers, even the "upgrade" market. So, in that regard, a 70mA PT and a 12k OT would probably give a greater difference.
Same .... I'm not trying to rain on yours either. I've always enjoyed following your discussions and appreciate your input!

I never made a final decision on a component swap unless I've had side-by-side amps to compare, for the exact reason that you stated. Our memories just aren't good enough. I've tried many transformers over the decades and none have made me say, "Whoa!" in the past, other than the BT1 and BT2 Hammond transformers that were in the oldest Traynor Bass Master amps. This is the first modern brand that's made me feel this way, I've never been giddy about current-manufacture OTs until I've tried these out.

My goal in this discussion is to share my experiences of using PAM's transformers, so that hopefully others feel confident to try them out. Once I do a side-by-side volume comparison test, I'll post the results here, but it may be a week or two.
 

jsnwhite619

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You wouldn't get any of that transfer power back but rather possibly recover some of the amp's clean audio power by way of less distortion from the non-linearity of the PT under load. I didn't mean to conflate the 2 power measurements, although they are related...

The bass is much clearer and more natural sounding than what I'm used to, I always found the amp a bit tubby sounding and that's completely gone now.

I have a feeling that these two are related. @sds1 point about extra clean power and @gabasa saying the bass is clearer I think may be confirming the effect of the 12k OT. From my numbers above, the 12k only requires 70% of the current draw as the "normal" 8k OT would require. So, if the PT is only needing to deliver 70% of it's spec rating when pushed at it's hardest, I imagine the bass will be tighter and hold together better even if the overall output is reduced. You shouldn't be getting any effects from the PT, whereas a normal 5e3 with all it's bass in circuit and a PT being pushed to it's 100% rating all the time is probably going to start to sag and get mushy bass. Theoretically... ;)
 

gabasa

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Here’s another perspective…

I brought up this topic because I believe that PAM used higher quality materials and better construction methods than most. However, they accommodate customizations. For example, I ordered a few tweed Bassman OTs with 4 Ohm outputs to accommodate 2x10 cabinet configurations; it just took a bit longer to receive my order.

You can just as easily order a 5E3 OT and specify an 8k primary. That way, you get exactly the spec you want but still have the benefit of the better quality construction. They’ll give you a part number for it which you can use for your future orders. None of the larger companies offer this kind of quality and service.
 

sds1

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You can just as easily order a 5E3 OT and specify an 8k primary. That way, you get exactly the spec you want but still have the benefit of the better quality construction.
I'm sure they make a nice product and you are obviously happy with what they sold you, but from the datasheets I've looked at everything they sell is custom spec, so what can be known about benefits from workmanship/materials?
 

gabasa

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I'm sure they make a nice product and you are obviously happy with what they sold you, but from the datasheets I've looked at everything they sell is custom spec, so what can be known about benefits from workmanship/materials?
I don't see a remake of a reverse-engineered specimen as a customization if the specs are exactly as measured, but that's just my opinion. If anything, it's a more authentic representation of the real thing.

A bunch of my guitar player friends have gigged with my Hammond-Bassman as well as my Pacific-Bassman. They all liked the Hammond one, so I'm not knocking it; they make a good product. However, these same players were all completely blown away by the Pacific one. I've watched four of my friends gigging with my Pacific-Bassman and stare at the amp in sheer awe in between songs, almost dumbfounded, because they never knew their guitars could sound so good.

To me, these are the benefits from materials and workmanship. I've done side-by-side listening tests with different primaries a couple of times in the past and I think that there's no way that 4.2k vs 4.7k could make such a profound, drastic difference in the playing experience.
 
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