A darker Fender Harvard?

[Alby]

Hey dinkotom, Any progress on your Harvard?.

I got mine up and running, sounds great, have not started the cab yet but have been playing it lots on the bench through a cab and it sounds wonderful.

I have a thread on this forum with a link to some pictures.

Alby

[hopy]

Hey dinkotom, Any progress on your Harvard?.

I got mine up and running, sounds great, have not started the cab yet but have been playing it lots on the bench through a cab and it sounds wonderful.

I have a thread on this forum with a link to some pictures.

Alby

Alby, I'm new here, but have been building/repairing for a while now. I was wondering, on your Harvard, what power transformer did you use? Since the Harvard was never as widespread as other models, I'm finding it a devil of a time finding a suitable tranny, I'm shooting to build the 5F10 and not the 6G10 since the 5F10 has more oomph. I'm thinking of using the transformer made for a Fender Deluxe, but don't know for sure if it's compatible. Thanks.

[dinkotom]

Hey dinkotom, Any progress on your Harvard?.

I got mine up and running, sounds great, have not started the cab yet but have been playing it lots on the bench through a cab and it sounds wonderful.

I have a thread on this forum with a link to some pictures.

Alby

Well, sadly, no change since my last post. Also, I used trannies intended for Harvard to build a Magnatone 213 clone, which is finished, but the vibrato does not work. As soon as I get it running (hopefully), Harvard is next. I'm sure this time I'll do it right.

[Alby]

Hey dinkotom, sorry to hear about your trem problems, I am sure you will figure it all out. It's too bad that we can't get to all of the projects that our creative little minds can think up.

Hopy, I used the Hammond 290AX which is what they recommend for the tweed Deluxe, the volatages are higher than what an original 5F10 transformer was but you can work on that once it's up and running. The Hammond 270DX is 275-0-275 which is probably what the original would have been since the rectified voltage on the original schematic is just over 300 volts.

Also, keep in mind that neither of these transformers have a bias supply tap so you will have to incorporate that into the schematic and figure out how to lay it out on your circuit board. Mine turned out pretty good, I had to play with some resistor values but it was not hard to get it to ther range required to properly bias the tubes. I am running at about 325volts with a bias voltage of -27volts. I can't remember the ma's or dissipation off the top of my head, I have it written down out in my shop somewhere in the pile of notes and papers on my bench.

You can see how the bias supply is put together in the pictures I posted on the thread I started for my amp.

Good luck
Alby.

[hopy]

Hopy, I used the Hammond 290AX which is what they recommend for the tweed Deluxe, the volatages are higher than what an original 5F10 transformer was but you can work on that once it's up and running. The Hammond 270DX is 275-0-275 which is probably what the original would have been since the rectified voltage on the original schematic is just over 300 volts.

Also, keep in mind that neither of these transformers have a bias supply tap so you will have to incorporate that into the schematic and figure out how to lay it out on your circuit board. Mine turned out pretty good, I had to play with some resistor values but it was not hard to get it to ther range required to properly bias the tubes. I am running at about 325volts with a bias voltage of -27volts. I can't remember the ma's or dissipation off the top of my head, I have it written down out in my shop somewhere in the pile of notes and papers on my bench.

You can see how the bias supply is put together in the pictures I posted on the thread I started for my amp.

Good luck
Alby.

Thanks Alby. Good info.

[Alby]

Alby, I'm new here, but have been building/repairing for a while now. I was wondering, on your Harvard, what power transformer did you use? Since the Harvard was never as widespread as other models, I'm finding it a devil of a time finding a suitable tranny, I'm shooting to build the 5F10 and not the 6G10 since the 5F10 has more oomph. I'm thinking of using the transformer made for a Fender Deluxe, but don't know for sure if it's compatible. Thanks.

I used the Hammond 290AX, which is used on the tweed Deluxe and others. It does not supply the ideal voltages and it has no bias tap but it works out fine if you plan it our correctly. Hammond also makes a 270DX which is 275 0 275 which would give you DC voltage closer to the 305 the original schematic calls for, keep in mind the tolerances on the schematic are + or - 20 % so maybe the 325 or so I am getting is acceptable. Both transformers are available on line for under $60. I have used the AX on a 5E3 and it works fine on that amp also. I am not aware of a premade Harvard board so I am assuming you are making your own as I did. You will have to incorporate the bias supply part of the circuit to your board which is extra work and expense over finding a transformer that comes with a bias tap.

My expectations for this amp were not very high, I figured it would be a bit of a toy but I am really impressed with the complexity of the tone. The tone control is really versatile and the 3 inputs each have a very distinct sound also. Go for it, you won't be disapointed.

Alby.

[hopy]

Thank you for the info Alby. Yes, I am making my own board. But first, I have to finish this Vibro Champ I'm building..... And I also have an old Alamo Capri that's in the middle of a complete overhaul I'm working on currently. The guy that tried to repair it before me did one helluva bad job.

[dinkotom]

Ok, completed it yesterday, sounds fine!
I'd like to try vox cut control in it - would this work?:

[tubeswell]

Ok, completed it yesterday, sounds fine!
I'd like to try vox cut control in it - would this work?:

Maybe you might have to play around with the value of the cap but no reason why that shouldn't work I guess

[macdillard]

I don't think you will like running the 6V6's at that low of an anode voltage.. I just finished a 5B3 that is set up such that I can switch B1 (anode voltage) voltage from 315 VDC to 340 VDC...The couple of guitar players that have tried it like the 340 VDC a lot better. The B3 does use different pre tubes but the major change is in the 6V6 voltage when it is switched.

[jackj]

Thought I'd let you know the G610 Harvard does exist .. I bought one yesterday ! It's a regular tweed Harvard cab with a tweed Princeton 5F2A inside including a 8" speaker. I guess Gibson isn't the only one who did odd stuff from time to time .

[RWood]

Could you post some pictures and give us the cabinet dimensions? Is there a tube chart?

Thanks for posting,

RWood