Tweed Deluxe Build - Transformers and Speakers

[TheTinMan]

I started a more detailed thread about this build on the Hoffman Amps forum but prefer to avoid asking about competing products on Doug's board. My design goal is to get as authentic a 5E3 sound/tone/feel as possible. Unfortunately, I've never played a real Tweed Deluxe which leaves me a bit handicapped...

The Mojo 756 has a 384-0-384 secondary - seems way high to me. And yes, I'll be using an NOS 5Y3 rectifier.

I'm considering one of two ClassicTone power transformers:
40-18021 with 355-0-355 secondary
-or-
40-18016 with option of 330-0-330 secondary (part # corrected)

Any input on choosing between these two? Any alternative that would be much better?
(Not to be rude, but I'm not open to Mercury Magnetics. This amp is for me - not to sell.)

For the output transformer, I am thinking seriously about the Mojo768sp. 8K primary with 4/8/16 secondary taps. I like the idea of a 4 ohm tap (parallel 8 ohm speakers, etc.), but this OT is rated for 25 watts. Too big/too much fidelity?

The ClassicTone 40-18022 OT has an 8K primary with 8 ohm secondary and is rated at 20 watts. Is that a "better" choice? Any alternatives screaming for consideration?

I've had good success with Weber speakers. The 12A100T description sounds about right but I worry that it might be too much "build it cheap just like Leo did". The 12A125S (P12Q replacement) might handle the amp's power better though and that seems to be what Ted recommended. Any comments/recommendations between those two would be great.

Thanks in advance for your thoughts,
Chip

[nosaj]

I started a more detailed thread about this build on the Hoffman Amps forum but prefer to avoid asking about competing products on Doug's board. My design goal is to get as authentic a 5E3 sound/tone/feel as possible. Unfortunately, I've never played a real Tweed Deluxe which leaves me a bit handicapped...

The Mojo 756 has a 384-0-384 secondary - seems way high to me. And yes, I'll be using an NOS 5Y3 rectifier.

I'm considering one of two ClassicTone power transformers:
40-18021 with 355-0-355 secondary
-or-
40-18061 with option of 330-0-330 secondary

Any input on choosing between these two? Any alternative that would be much better?
(Not to be rude, but I'm not open to Mercury Magnetics. This amp is for me - not to sell.)

For the output transformer, I am thinking seriously about the Mojo768sp. 8K primary with 4/8/16 secondary taps. I like the idea of a 4 ohm tap (parallel 8 ohm speakers, etc.), but this OT is rated for 25 watts. Too big/too much fidelity?

The ClassicTone 40-18022 OT has an 8K primary with 8 ohm secondary and is rated at 20 watts. Is that a "better" choice? Any alternatives screaming for consideration?

I've had good success with Weber speakers. The 12A100T description sounds about right but I worry that it might be too much "build it cheap just like Leo did". The 12A125S (P12Q replacement) might handle the amp's power better though and that seems to be what Ted recommended. Any comments/recommendations between those two would be great.

Thanks in advance for your thoughts,
Chip

Then your on a pipe dream. Building something to sound like something your not sure about. Just build the kit and hear how it sounds, you might like it better than a real one. Let your ears be your guide.

Any of Leo's cheapness is highly regarded today so why knock it. Cheap stuff in the right hands can great.
Perfection always gets in the way of progress, like a project never started.
nosaj

[ThermionicScott]

Then your on a pipe dream. Building something to sound like something your not sure about. Just build the kit and hear how it sounds, you might like it better than a real one. Let your ears be your guide.

Any of Leo's cheapness is highly regarded today so why knock it. Cheap stuff in the right hands can great.
Perfection always gets in the way of progress, like a project never started.
nosaj

+1. Don't be afraid of cheap -- oversized transformers and high-power speakers will take away from the authentic vibe. But OTOH, it would still probably sound good in its own way.

The Mojo 756 is probably good iron, but there are already enough threads about people having to use band-aids (dropping resistors and Zeners) to get their amp builds to work right. Yuck. The very early Deluxes used a PT rated for 700VAC and 80mA. Even though the 40-18016 (40-18061 is an output transformer) is rated for lower voltage, it has a higher current rating, so it's not going to sag as much when built into a 5E3. It would get my vote.

For an example, I use a 340-0-340/140mA transformer in mine, and the voltage lands right around 370V with 6V6s and a 5Y3. I wouldn't want to use anything that pushes the voltage higher.

Hope this helps. Buy some parts and dig in!

[TheTinMan]

The suggestion by Barfoden in post 14 of THIS THREAD of a ClassicTone 40-18078 power transformer brings up an interesting possibility.

AFAICT plate voltage should be in the 350-370 range for vintage 5E3 tone & feel. A 330-0-330 secondary should hit that ballpark with an NOS 5Y3GT rectifier.

ClassicTone's 49-18078 has two secondary high voltage windings. One 330-0-330 and another 355-0-355. Unlike the 18-016 I asked about initially, this PT is only rated for 100ma and has low voltage power ratings similar to "true" 5E3 values.

My potentially goofy idea is to use an on-off-on DPTT switch in the Ground spot that is a standby switch and let's me select vintage or higher voltage. I also could add more power supply filtering to the higher voltage option, lowering noise and making the power rail stiffer.

[ThermionicScott]

The suggestion by Barfoden in post 14 of THIS THREAD of a ClassicTone 40-18078 power transformer brings up an interesting possibility.

AFAICT plate voltage should be in the 350-370 range for vintage 5E3 tone & feel. A 330-0-330 secondary should hit that ballpark with an NOS 5Y3GT rectifier.

ClassicTone's 49-18078 has two secondary high voltage windings. One 330-0-330 and another 355-0-355. Unlike the 18-016 I asked about initially, this PT is only rated for 100ma and has low voltage power ratings similar to "true" 5E3 values.

My potentially goofy idea is to use an on-off-on DPTT switch in the Ground spot that is a standby switch and let's me select vintage or higher voltage. I also could add more power supply filtering to the higher voltage option, lowering noise and making the power rail stiffer.

I have yet to take a good picture of it, but I did a very similar thing with my amp:



A DPDT switch (located on the bottom of the chassis to keep from cluttering up the control panel) selects which HT secondary gets connected to the rectifier tube. I used a Weber W25130 power transformer, so the options are 270-0-270 and 340-0-340. There are audible things to like about both settings, but apart from early testing, I've tried not to switch it while the amp is on.

[danman]

I built the same amp last year and was curious about what PT to use. Upon a recommendation from Bruce at Mission Amps, I went with the 40-18016 from Classictone and it delivers a perfect 360vdc at the plates with a wall voltage of 122vac. It does not come with center-tapped filament winding like some of their other models though. It is easy enough to create an artificial one with 2 100ohm resistors tied to ground or elevated and tied to pin 8 on one of the 6v6 sockets.

[TheTinMan]

Danman - thanks very much for your voltage results. That's exactly what I needed to know. It's hard to go wrong with Bruce Collins' advice AFAICT.

OK - here are my choices:

Output Transformer - ClassicTone 40-18022 8K primary/8 ohm secondary, rated for 20 watts

Power Transformer - ClassicTone 40-18078 dual high voltage taps 330-0-330 and 355-0-355, rated for 100 ma HV DC
(the 40-18016 looks like a good choice too but is rated for 120ma and physically is much bigger than this one)

Speaker - Weber 12A125A

Chip

P.S. I'll start another thread with build pics once it's done.

[ThermionicScott]

Danman - thanks very much for your voltage results. That's exactly what I needed to know. It's hard to go wrong with Bruce Collins' advice AFAICT.

OK - here are my choices:

Output Transformer - ClassicTone 40-18022 8K primary/8 ohm secondary, rated for 20 watts

Power Transformer - ClassicTone 40-18078 dual high voltage taps 330-0-330 and 355-0-355, rated for 100 ma HV DC
(the 40-18016 looks like a good choice too but is rated for 120ma and physically is much bigger than this one)

Speaker - Weber 12A125A

Chip

P.S. I'll start another thread with build pics once it's done.

Awesome, no need to start multiple threads, though -- I much prefer reading about projects from conception to success in one thread.

[d. spree]

yes, I've built a few tweed deluxes and I love the wound of the weber 12A125As