Tweed Twin Output Transformerthinkin

[rymac]

I'm thinking about changing my output transformer.
The amp is a 5F6A circuit in a 2X12 cabinet 4 ohm load.
The power transformer I have is for 2 6L6 tubes and the B+ is 470vDC.
I'm looking at the "Tweed Twin Low Power Output Transformer"
at Mojo Musical Supply. Part #MOJO767. Will this work?
Is this made by Heyboer with paper wound bobbins?

Rymac

[Chuck H]

I have no personal experience with that tranny, but it looks pretty beefy. The low power designation is likely just to indicate that it is their best OT for the tweed era "Twin" amp. It should handle the extra power OK. You could just contact MOJO and ask them too.

As for the other criteria you mentioned...Well, JMHO, but paper shmaper. There's an awful lot of lore floating around (and you know what else floats!?!). Paper does not make better sounding transformers. Paper has no electrical properties. The higher temp, lower moisture absorbtion products used by modern transformer MFG's work far better than paper. The lore stems from the fact that alot of plastic bobbin transformers are made overseas as cheaply as possible. As a result, they are mediocre at best. But many quality products use modern materials to improve on past designs. The rub is that in the hayday of tube tech, paper was the commonly used insulation material. So some of the better sounding transformers have employed it's use. Now that technology has moved on into transistors, Tube tech is substantially lacking in transformer design consideration. Some transformer MFG's just try to copy what was good in the past without trying to understand "why". So some advertise "paper bobbins" as if it were a good thing. Only because you can now be sure that the MFG took every possible measure to make the new OT as good as the old ones used to be. It's a bunch of hogwash cork sniffing if you ask me. Hammond manufactures transformers with modern materials that are more durable and reliable as a result. They also know how to make a transformer. So they don't have to copy a known formula to get something right. Point is... Anyone advertising "paper bobbins" as a good thing is either playing a marketing angle because they think you are ignorant. Or they are ignorant.

Chuck

[Bruce / Mission Amps]

The MOJO 767 is a very good output tranny... I've used plenty of them and have the experience with them to go with that statement.
Yes, I've used Mercury Magnetic trannys too but, Mercury Magnetics uses plastic bobbins on their trannys and everyone seems to still like them... I think they do it because it is much cheaper to manufature and for no other reason.
But, MM still shoves it up your a$$ with costs while the Heyboer trannys from MOJO are built much more like real vintage trannys (Kraft paper, interleaves, and a paper bobbin). They do not cost as much as the MM ones but they still sound excellent too.

[Chuck H]

For the record I was not saying paper bobbin transformers are bad. It must be rare for moisture absorbsion to become a problem since I have never seen a case of it myself. But I have heard of it. In fact I will be using some paper bobbin and interleaved trannys in my next design. I just get a little steamed when I see guys who WANT paper. Like it has some kind of tonal advantage. This lore is perpetuated by manufacturers who advertise "paper bobbin"...Oh well, give 'em what they want, eh. It's fair to say that some MFGs simply still do it that way. And I suppose if it were me, and I could sell a few more units by saying so, I probably would.

Chuck