Transformer Choices, Mojo, Allen, Mercury

[PeaveyBandit]

Going to buy some trannies for a new replica princeton build I'm getting advice for over in the "mods tweaks" forum and I have a general question I thought might belong in this section.

I'm going to install a Deluxe OT and a good PT that could handle 6L6's if I ever wanted to try that option. But the PT and OT are about 105.00 dollars total on Allen Amps site and I think these are just Heybeur brand. I know they are probably good and might even be the same thing Mojo sells. In any case I usually buy or like the Mercury Magnetics but we're talking a lot more money for them around 220 list and less on the street. I'm wondering not only if the Mercury's are worth the extra cost but also the "best choice".

Any input appreciated. I don't mind going for the Mercury's if they are really better. I know this is a highly opinionated thing. I'm betting they are both excellent products but will I hear a difference and will they be different in longevity and reliability.

[Bruce / Mission Amps]

Going to buy some trannies for a new replica princeton build I'm getting advice for over in the "mods tweaks" forum and I have a general question I thought might belong in this section.

I'm going to install a Deluxe OT and a good PT that could handle 6L6's if I ever wanted to try that option. But the PT and OT are about 105.00 dollars total on Allen Amps site and I think these are just Heybeur brand. I know they are probably good and might even be the same thing Mojo sells. In any case I usually buy or like the Mercury Magnetics but we're talking a lot more money for them around 220 list and less on the street. I'm wondering not only if the Mercury's are worth the extra cost but also the "best choice".

Any input appreciated. I don't mind going for the Mercury's if they are really better. I know this is a highly opinionated thing. I'm betting they are both excellent products but will I hear a difference and will they be different in longevity and reliability.

I don't think Allen is using Mercury Magnetics at all.
Over the years I know Dave has used many of the same high quality winders I do but he'd advertise them as MM if they were.
My honest opinion is that MM trannys are excellent too but many times just way over priced for what they are.
MOJO uses Lenco and Heyboer too, another pair of great winders.
Remember what I said though... the Deluxe Reverb uses a different impedance OT then the Princeton, which is close to 8500 ohms.... and 6L6 version needs to be about 1500 to 2000 ohms less then the lower zed 6500 ohm Deluxe so.... if you are not careful, you'll end up with an amp that does everything you want but, except for one, possibly mundane too.
You might not recognize this at first but with time you'll start to hear things differently.

[PeaveyBandit]

Help me get my head straight please. I'm going to buy one of the princeton PTs that can handle a more demanding filament circuit. Not sure which brand yet but the ones on the Allen site look good. So does Mercury. All this based in a replica '64 BFPR chassis.

Now on the OT I figured I'd be installing a Deluxe OT , two 6V6s, 12 inch 8 ohm speaker and that stage would be okay. Then if I ever change to 6L6 all I have to do is install something like a Vibroverb OT a maybe some other small changes but done. Is there some other part I'm skipping?

Thanks!
PB

[Bruce / Mission Amps]

Help me get my head straight please. I'm going to buy one of the princeton PTs that can handle a more demanding filament circuit. Not sure which brand yet but the ones on the Allen site look good. So does Mercury. All this based in a replica '64 BFPR chassis.

Now on the OT I figured I'd be installing a Deluxe OT , two 6V6s, 12 inch 8 ohm speaker and that stage would be okay. Then if I ever change to 6L6 all I have to do is install something like a Vibroverb OT a maybe some other small changes but done. Is there some other part I'm skipping?

Thanks!
PB

If you are convinced that a reissue Deluxe Reverb output transformer is the way to go with this amp, you can run a pair of 6L6 with a well made Deluxe Reverb OT if you keep the power tube bias current down a little so the two power tubes (with respect to the actual plate current x's plate voltage) are not more then around 13-15 watts for each tube.
With a good rectifier, any well made 130ma to 150ma power tranny can run a pair of class AB 6L6s to about 25 to 30 watts output.
The higher current rated power tranny from Allen is good to use and not overpriced.
However... your amp is drifting further and further away from a Princeton Reverb and closer to a generic, cathodyne driven Deluxe Reverb or a 6V6-6L6 version of low power cathodyne driven Pro/Vibrolux/Bandmaster Reverb.
All the things you want to keep changing in the standard PR are the main reason a Princeton Reverb sounds the way it does.
So, all your mods are fine if that is what you are going for... but you now need to stop calling your project a Princeton Reverb, ha ha ha.
At the least, from what you are telling us, it will be a cathodyne phase inverter/driver... Deluxe Reverb.

[PeaveyBandit]

Hi Bruce,

Thanks for the great advice. I'm probably not going to go that far with it. I love both the deluxe and princeton so I'm going to stay half way between them. It will basically be a genetic clone of the Princeton with a 12" speaker, DR OT, and one or two mods like the stokes and PaulC. 'm going to experiment with the other mods I've learned here but in my mind it's going to be something like a PR on steroids. I have a hunch if I do this right I'll be happy with the tone too. As long as it's louder than a princeton with more bass and sounds like PR or DR or some blend of the two I'll be thrilled but we'll see. I might test with both OTs before committing. I just don't know yet. But thanks again everyone for reading and those who commented.

PB

[merkaba22]

If you are convinced that a reissue Deluxe Reverb output transformer is the way to go with this amp, you can run a pair of 6L6 with a well made Deluxe Reverb OT if you keep the power tube bias current down a little so the two power tubes (with respect to the actual plate current x's plate voltage) are not more then around 13-15 watts for each tube.
With a good rectifier, any well made 130ma to 150ma power tranny can run a pair of class AB 6L6s to about 25 to 30 watts output.
The higher current rated power tranny from Allen is good to use and not overpriced.
However... your amp is drifting further and further away from a Princeton Reverb and closer to a generic, cathodyne driven Deluxe Reverb or a 6V6-6L6 version of low power cathodyne driven Pro/Vibrolux/Bandmaster Reverb.
All the things you want to keep changing in the standard PR are the main reason a Princeton Reverb sounds the way it does.
So, all your mods are fine if that is what you are going for... but you now need to stop calling your project a Princeton Reverb, ha ha ha.
At the least, from what you are telling us, it will be a cathodyne phase inverter/driver... Deluxe Reverb.

I hope I am not hijacking this thread too by introducing the Princeton Reverb II into the topic; but since it is not a Princeton Reverb per se and I could only find one thread/posts, ask to be forgiven in advance

I just bought a 1984 PR II with a ScumBack H75 and am looking to use it as a platform which (while keeping the clean side) to take advantage of all the great improvements we've seen on the gain side in the past 25 years in view of the Trainwreck/Dumble and inspired descendants (the Komet seems close but I don't have that kind of money yet) -- also since, it the PR II is quite old I have been recommended to replace the OT PT and Choke with, preferably, Mercury Magnetics, to start; maybe to allow 6L6s as well. The other aspect of this may be discussing whether to use a Fender or Marshall style transformer, for example, or something in between, so to speak.

If there are other options on these replacements or other insights regarding caps, etc. on achieving my intents, any observations would be gratefully received.

[daz]

Just to inject a little dose of reality, i just put a hammond OT in a marshall JCM style build that took this amp that i spent 3 months tweaking from hopeless to perfect. Actually when i say hopeless i don't mean to imply it was horrible sounding. But it did have issues that i could never quite get right after endless changes. So don't count out hammond or any trannys just because people build other companies up like thier iron is gonna make any amp better. My amp's tone went thru the roof with a budget OT !

[Chuck H]

Hey, Daz,

So you tried the Hammond. Did you go with "off the shelf" or one of their "guitar amp" OTs?

Glad to hear it gave you more of what you wanted. Remember, no matter what anyone one says about any other transformer MFG, Hammond has been making musical instrument amplifier transformers longer than almost anyone. Certainly longer than MM or Heyboer. I use their off the shelf units for many builds. The 1608 OT kills for an 18 watt type 2 x EL84 amp.

Glad it worked out

Chuck

[daz]

I used the 1750N which is a marshall JCM/JMP replacment. I'm totally sold on them. If it can sound much better than a Heyboer with about the same specs, they are certainly top notch. The touch sensitivity of the amp went from lousy and kinda wierd in a way i can't quite explain, to superb. Sounds like the best JCM 800 i've ever had but better....more complex and dynamic. (owned 3 including one of the first years) Not sure if i'll be building any more amps, but if i do i'm going straight to hammond for all trannys and chokes.

Oh, and if i decide to redo my 18 watt i'll surely go with the 1608. I believe you !

[Steve Conner]

Daz, that's good to hear that you finally got your Marshall hassles sorted

[daz]

Thanks. It sure is. I was going crazy with this damn thing. Now i actually WANT to mess with it because now i can try new things for fun to see how perfect i can get it instead of desperatly trying to make it usable. i may even try reverb.

[PeaveyBandit]

I used several MM trannies and had a hum issue. I moved to the Heyboer made trannys mfg for and sold by Allen Amps. They were half the price, paper bobbins, nice shield and they sound great, look great and NO HUM whatsoever. I learned a good lesson about aggressive advertising vs reality. Oh yeah and they came with a nice metal bell cover vs the MM's which you have to ask for.

[TheTinMan]

I used several MM trannies and had a hum issue. I moved to the Heyboer made trannys mfg for and sold by Allen Amps. They were half the price, paper bobbins, nice shield and they sound great, look great and NO HUM whatsoever. I learned a good lesson about aggressive advertising vs reality. Oh yeah and they came with a nice metal bell cover vs the MM's which you have to ask for.

Dave Allen sells great iron, but IMHO you're not being fair to Mercury Magnetics. They try to make exact replicas of specific vintage transformers, nothing more and nothing less (at least in the ToneClone line). Are they worth the $$$ ????? That's for you to decide, but I doubt the hum was the fault of your transformers.

+1 on all of Bruce's comments about moving away from a Princeton Reverb. 12" speaker, bigger OT, higher voltages (possibly), major tweaks to the phase inverter, and it's a different amp. Not bad - just different. I've heard of at least one very successful AA1164 circuit with a beefier OT, 6L6s, a 12" speaker, and a choke.

Chip

[PeaveyBandit]

I'm being completely fair. And I mean that respectfully. I have owned countless original Fender trannies with no hum. Sure I may have to install a couple of 100 ohm resistors from time to time but they dont have the issues I had with the MMs. I also realize not all MMs have an issue. What I do know is that I'm not hearing any decrease in tone or quality in the ones I've moved to. So my argument is that I'm giving a simply accurate evaluation of my experience. No disrespect. Just my experience, thanks