Underpowered OT?

[kriswel]

For some reason I ordered the wrong OT, I think I meant to get the 1650F with the 290BX but ordered the 1620 by accident. Without really checking things over I assumed I had a good pair and built an amp. Fixed bias 6V6 pair AB763 Lite. It sounds amazing but I have been asked to build ten for a local company and while pricing it out I found my screw up. Or was it? Yes it is underpowered but that might be why it sounds so good... will somebody kill it? Is it worth a chance?

I think I have to order the 1650F and let him try it with the new transformer. Or could I use the same PT and drop the voltage a little to get it within a tolerable range?

PT=290BX 330-0-330
http://www.hammondmfg.com/pdf/EDB290BX.pdf

OT=1620

20 watts
6,600 ct Primary
4-8-16 Secondary

[tubenit]

I am using a 300-0-300 PT with 1620 running a pair of 5881's in my Tweed Overdrive Special. Sounds great,IMO.

I am using a 1620 with 6V6's in my Tweed BluezMeister.

I have also used a 1650F with 5881's and a similar PT.
The difference is the bass seemed a little tighter with the 1650F.

With respect, Tubenit

[Geezer]

I say if you've got a winning combination, stay with what you've got.

The OT you have can handle (is made for) 2x6V6's....yes, you are pushing it to more saturation, but that is contributing to the tone you're hearing. A different/larger/beefier unit is going to sound tighter & , well...different.

Besides, Hammonds are notoriously over-built. I wouldn't have a problem at all with sticking with that OT. I think you have a "happy screw-up".

G

[kriswel]

Thanks for the advise.

Maybe I need to put it through it's paces a bit. Put the ear muffs on and rock it like I was 15 again for an extended period and see how it holds up. I would just need to check and see if the OT is getting hot right?

[DummyLoad]

1620 would be very similar to deluxe / deluxe reverb p-p 6V6 plan.

1650F would be similar to princeton reverb plan w/ much lesser to nil saturation characteristics.

either transformer will add BW.

use of 1650F in your existing ckt. likely to increase B+ slightly.

i'd bet either sounds great and either can handle a proper biased 6V6 pair with ease.

are they the new and improved models w/ easy wire secondaries.  

personally, i'd opt for the deluxe-like (1620) plan. :p

;)  

--ISO

[PRR]

20W rating seems ample for two 6V6.

A somewhat under-rated output transformer won't run hot enuff to matter. It will distort the bass. Yes, whup it like you were 15 again. But Hammond's 20W rating is probably more than any 2-6V6 gitar amp needs, and distortion rise in the bottom octave is not bad for guitar.

[Ritchie200]

Correct me if I am wrong, but isn't that rating for reproducing 20-25,000 Hz?  I doubt it would get warm at full tilt.

Jim

[harryk]

I have used Hammond 1620 in many amps. I put one to an amp with plexi style poweramp with a pair of 2xEL34 tubes producing some 40-50 W. It is by now one of the best sounding amps that I have made especially with distorted sounds. I think that OT core saturation is on reason for that sound.

[topbrent]

Fixed bias 6V6 pair AB763 Lite.     It sounds amazing....
20 watts
6,600 ct Primary
4-8-16 Secondary

Sounds like a cool little amp.  Do you have any pics of your build?

[kriswel]

We are going to build ten of them. We are still working on cosmetics. I will post some pictures as I go.

Thanks for the input again.