Tweed Deluxe Output Transformer Upgrade Experience

gabasa

Tele-Holic
Joined
Jan 29, 2018
Posts
767
Age
51
Location
Toronto, ON
Hey everyone,

I recently had an amazing experience with Pacific Audio Magnetics output transformers in tweed Bassman and blackface Bassman builds. I love the sounds of these things so much that I ordered three more output transformers to upgrade the existing amps in my collection; one for my 2x10 tweed Bassman build, one for my tweed Harvard build and one for my 5E3 build.

I installed the PAM OT into my 5E3 last night and again I’m amazed at the improvement. The amp now has a beautiful, vintage sweetness to it that’s tough to put into words. As with the Bassman amps, this 5E3 now sounds so good that I feel there would be nothing to be gained tonally by purchasing a vintage original amp. Yes, it sounds that good. Previously, the amp had a Mojotone 50246 OT in it, which on its own was a special one. It’s the only transformer that Mojotone sells that’s built by Lenco, and is the exact same transformer that Victoria uses for their 20112 amps. In side by side tests, this amp with the Victoria/Lenco OT sounded noticeably better to my ears than an otherwise identical amp that was loaded with a Classictone OT. This new one is yet another improvement.

The reason I’m posting this is to share my excitement about PAM so that hopefully, other DIYers will get to enjoy their products as much as I have. They’ve been making premium transformers for decades and a while ago they started selling directly to consumers. Fwiw, I have no affiliation with them and don’t even live in the same country.

I’ve used Hammond, Classictone, Mercury, Lenco and Heyboer in the past. They’re all good but to my ears, there’s something to these Pacific OTs that all the others lack. Keep in mind that I’ve only used their tweed Bassman and tweed Deluxe OTs so far, so I can’t comment on other models.

Whether you’re building a new 5E3 or already enjoying one you’ve previously built, consider treating yourself to one of these.

46C5A695-4E33-451C-8178-60758A0448C0.jpeg
 

sds1

Friend of Leo's
Joined
May 4, 2017
Posts
2,154
Age
46
Location
Orlando, FL, USA
They’re all good but to my ears, there’s something to these Pacific OTs that all the others lack.
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.
 

schmee

Telefied
Silver Supporter
Joined
Jun 2, 2003
Posts
21,167
Location
northwest
I generally felt the tranny maker made little difference, but the specs could make a huge difference.
But when 20 years ago my 65 BFDR blew an Output Tranny I found out differently. I didn't work on my amps back then so took it to the local repair guy. He put a New Sensor OT in. TERRIBLE! That amp never sounded right. I bought a Mercury Magnetics tranny (they were not abusively expensive back then) and damn! That sounded good.
 

gabasa

Tele-Holic
Joined
Jan 29, 2018
Posts
767
Age
51
Location
Toronto, ON
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 can’t put it into words, but it sounds more like a vintage Fender, and less like a modern attempt. The tonal balance is amazing from bass to treble, and the attack is somehow sweeter, all in a way that reminds me of a vintage original. As soon as I turned the amp on, my first thought was that I could sell the entire amp collection and be happy with this 5E3. I never used to feel like this before I discovered PAM, but YMMV.

From what I understand, they reverse engineered a great sounding one that was provided to them by George Alessandro, instead of following the original Triad blueprint. Apparently, primary impedances were often different in reality than on paper.

This reminds me of the tweed Bassman build issue. Fender’s 5F6-A schematic isn’t what was in production amps. Which is correct?
 
Last edited:

gabasa

Tele-Holic
Joined
Jan 29, 2018
Posts
767
Age
51
Location
Toronto, ON
I generally felt the tranny maker made little difference, but the specs could make a huge difference.
But when 20 years ago my 65 BFDR blew an Output Tranny I found out differently. I didn't work on my amps back then so took it to the local repair guy. He put a New Sensor OT in. TERRIBLE! That amp never sounded right. I bought a Mercury Magnetics tranny (they were not abusively expensive back then) and damn! That sounded good.
Winding methods
Layered insulation material vs bobbins
Quality and temperature grading of magnet wire
Lamination materials
Winding ratios

So many things can make a difference in the end result. Larger, for-profit companies have different end goals than smaller, specialized manufacturers, perhaps?

For example, Hammond’s tweed Bassman OT has a lot less bass and a lot more treble than any other brand, even though on paper, it does the same job.
 

gabasa

Tele-Holic
Joined
Jan 29, 2018
Posts
767
Age
51
Location
Toronto, ON
There are tons of OT manufacturing variables. I'm sure many of them could make one brand of OT sound different from another. But I'm even more sure size and specs matter.
I agree, but how an amp sounds on a stage in front of a crowd, and makes the player feel, outweighs everything. I’ve let several local guitar players, all very experienced, take my tweed Bassman for a spin lately. Every single one of them has commented that it’s the best amp they’ve ever played in their lives, and a few offered to buy it, but I won’t sell it. Even their band mates commented similarly.

I’ve learned recently that my Bassman has been the topic of conversation between some of these guitar players, which was nice for me to hear. I’ve been modding or building amps on and off for decades and I’m convinced that these transformers are this good.

After playing guitar for 38 years, I’m convinced that the quality of the output transformer is crucial to getting the sound you’re after. It’s the heart and soul of a guitar amplifier.
 
Last edited:

schmee

Telefied
Silver Supporter
Joined
Jun 2, 2003
Posts
21,167
Location
northwest
A Princeton Reverb can be a marginal amp for gigging in many situations. Big rooms just take too much and they can be too nasty.

I have a '71 I bought that the chassis was pretty hacked. I had a DR output tranny in it for a long time and it helps.
But the huge change in clean headroom was when I put a Vibrolux Reverb power tranny in it. Wow, it made a big difference. Before that I figured a power tranny, if at the right voltage, wouldn't matter that much. Wrong I was!
 

gabasa

Tele-Holic
Joined
Jan 29, 2018
Posts
767
Age
51
Location
Toronto, ON
Before that I figured a power tranny, if at the right voltage, wouldn't matter that much. Wrong I was!
Yes ... the specs of the transformers we use matters greatly, while the implementation of those specs via manufacturing methods and material selection gives us the end result, which can be for better or for worse. If this weren't true, we'd all be using cheap, offshore transformers and IMO our amps would sound as good as vintage.

Collectively, us internetters are not that good at understanding how specs affect end results, because we're prone to so much hearsay online; we're much better at playing and deciding for ourselves, but we don't take the time to do this often enough.

For me, if I had two OTs lying around that had 8k and 12k primaries but were otherwise identical, I'd listen to them both before picking the one I like.
 
Last edited:

printer2

Poster Extraordinaire
Joined
May 24, 2010
Posts
8,640
Location
Canada
Not only is the winding methods and materials going into them that may have an effect also there are different types of steel used for the laminations. The OT is one place where I think mojo matters. Caps and resistors, not so much.
 

sds1

Friend of Leo's
Joined
May 4, 2017
Posts
2,154
Age
46
Location
Orlando, FL, USA
Apparently, primary impedances were often different in reality than on paper.
And everyone else is just building to the paper spec.

I didn't check yet, does the Bassman OT that you like so much by Pacific also have a different primary independence than vintage spec?
 

Snfoilhat

Tele-Afflicted
Joined
Apr 8, 2016
Posts
1,561
Age
41
Location
Oakland, CA
It’s in the nature of an output transformer (like how long it takes to swap them into the same amp) that people seldom hear them A/B with any of the kind of rigorousness that would convince people one sound was different and that the OT was the reason. Recordings would make this case better, and being confident that there is a difference is should precede figuring out which aspect of the specification is responsible for the difference. Otherwise it’s easy to get seduced by how good your own explanations are (e.g it’s got to be the brand, it’s got to be the higher primary impedance, the bigger core, etc) and the favored explanation goes looking for anything it can find to help confirm it
 

gabasa

Tele-Holic
Joined
Jan 29, 2018
Posts
767
Age
51
Location
Toronto, ON
And everyone else is just building to the paper spec.

I didn't check yet, does the Bassman OT that you like so much by Pacific also have a different primary independence than vintage spec?
Their tweed Bassman OT has a 4.7k primary impedance, I think that the vintage spec on paper was 4.2k.

My old 2x10 Bassman build has the Hammond 1760L OT. Earlier this year I built two identical amps for two of my friends, and the only difference in their amps to mine was that I used Pacific's output transformers for theirs. There's no comparison, the Pacific sounded way better side-by-side, and everyone agreed. I actually have Pacific's tweed Bassman power and output transformers on my bench right now to upgrade my 2x10.

Click on the link below if you want to see two Bassman amps that I built for myself earlier this year. They turned out great!
 
Last edited:

gabasa

Tele-Holic
Joined
Jan 29, 2018
Posts
767
Age
51
Location
Toronto, ON
It’s in the nature of an output transformer (like how long it takes to swap them into the same amp) that people seldom hear them A/B with any of the kind of rigorousness that would convince people one sound was different and that the OT was the reason. Recordings would make this case better, and being confident that there is a difference is should precede figuring out which aspect of the specification is responsible for the difference. Otherwise it’s easy to get seduced by how good your own explanations are (e.g it’s got to be the brand, it’s got to be the higher primary impedance, the bigger core, etc) and the favored explanation goes looking for anything it can find to help confirm it
Yeah, it has to be side-by-side tests. However, two OTs with the exact same specs can sound very different depending on their materials used and manufacturing methods, so sometimes the difference has nothing to do with the spec and more with the implementation of it.

I had identical Bassmans, identical Champs, identical Harvards and identical tweed Deluxes to work with, and did these types of side-by-side tests a lot because I find it interesting and it's been kind of a hobby. I also had a pair of tube-rectified, '60s Traynor Bass Master heads that were impossible to tell apart blindfolded. I did listening tests on those two amps for many years, swapping out components one at a time so that, for my tastes at least, I can figure out what works for me with a degree of honesty.
 

SacDAve

Poster Extraordinaire
Silver Supporter
Joined
Dec 23, 2009
Posts
7,830
Age
70
Location
Rocklin Ca.
A couple years I built two 5E3's with identical components, speakers, tubes, cabinets the only difference was transformer sets one had Classic Tone the other Mercury Magnetics the MM had a better sound you could tell but was it worth the extra money for the Mercury Magnetics at the time I didn't think so.
 

RetiredUnit1

Tele-Holic
Joined
Jun 18, 2022
Posts
830
Age
66
Location
SoCal
Ouu.... a new IRON manufacturer, right here in SoCal? Mercury Magnetics is only 10 minutes from my house, and I have the maximum discount after a gazillion purchases.

But hey, I'll try anything new. I added them to my home made HTML homepage, next to AnTek which makes TOROIDAL guitar amp iron!

1658696133825.png
 




Top