I just acquired a 2x6L6 chassis from a dead Baldwin organ (Pics here - basically transformers and tubes) and I'm trying to decide what to build out of it.
I have been reading and studying up, trying out the Duncan power supply designer, finding my way through what is realistically useable, for what and why.
Here's what I've got: The HT voltage across the PT secondaries is 525v on my 127v AC wall voltage. It is center tapped. So, roughly 260-0-260 with no load.
As I understand it, if I go with UF4007s to rectify I will have about 365vdc of B+ to work with. If I stick with the 5U4GB that the Baldwin organ was designed
with, that drops about 50v to 315 or so. The PT has 4v, 5v and 10v heater taps. The thing is a monster, huge and heavy.
Prior to taking the measurements and seeing the relatively low voltage, I was pretty sure I'd be building a Bassman. They all want to see around 430v.
Because of the PT specs, I'm not wedded to using the 6L6s. My initial thought was to wring as much loud-clean out of it as I could, but I've backed off of that,
and just want to build something different than what I've done in the past. (Champ/5F2a, Hammond 18 watt conversion)
If I'm not reading the schematic wrong, a tweed Harvard wants to see 305v at the first filter cap node. Such a big hunk of iron for that circuit, though..
Also -- The OT has a roughly 20:1 winding ratio, so roughly 6100 primary impedance under a 16 ohm secondary load.
SO -- Ideas..?
I have been reading and studying up, trying out the Duncan power supply designer, finding my way through what is realistically useable, for what and why.
Here's what I've got: The HT voltage across the PT secondaries is 525v on my 127v AC wall voltage. It is center tapped. So, roughly 260-0-260 with no load.
As I understand it, if I go with UF4007s to rectify I will have about 365vdc of B+ to work with. If I stick with the 5U4GB that the Baldwin organ was designed
with, that drops about 50v to 315 or so. The PT has 4v, 5v and 10v heater taps. The thing is a monster, huge and heavy.
Prior to taking the measurements and seeing the relatively low voltage, I was pretty sure I'd be building a Bassman. They all want to see around 430v.
Because of the PT specs, I'm not wedded to using the 6L6s. My initial thought was to wring as much loud-clean out of it as I could, but I've backed off of that,
and just want to build something different than what I've done in the past. (Champ/5F2a, Hammond 18 watt conversion)
If I'm not reading the schematic wrong, a tweed Harvard wants to see 305v at the first filter cap node. Such a big hunk of iron for that circuit, though..
Also -- The OT has a roughly 20:1 winding ratio, so roughly 6100 primary impedance under a 16 ohm secondary load.
SO -- Ideas..?
Jeru,
You probably are not getting a lot of replies coz your question is too vague.
365V B+ is not a problem in fact some of us think that 6L6 Amps and EL34 Amps (in particular) actually sound better at around this voltage rather than the more typical 450V or so.
So a Bassman is NOT off the radar.
You will get more like 35 Watts rather than 50 Watts be some of us think they are "better" Watts.
If you give us a hint about what sort of music you like to play we can maybe recommend a circuit.
Are you a Death Metal Shreader, Classic Rock or a Folk and Blues guy?
Do you use a lot of pedals between the guitar and the amp?
I'm about to dissappear for 2 weeks but your answers will help others guide you.
For your possible interest here is a "Junkbox Trainwreck" I built out of an old Philips PA Amp where the B+ was 380V. It is drop dead gorgeous. You could easily sub 6L6 into this circuit. The Power amp schematic is pretty "generic" and could be used as is with 6L6 and your existing output tranny. The preamp is the classic Trainwreck Express with a parallel input tube modification of my own design. It takes pedals fairly well. The chassis has enough tube sockets to do a really High Gain preamp if you wanted but if this is to be your firsst build I would probably advise against it, the more complicated the circuit you select then the more things that can go wrong and the harder it maybe to set to work.
Cheers,
Ian
You probably are not getting a lot of replies coz your question is too vague.
365V B+ is not a problem in fact some of us think that 6L6 Amps and EL34 Amps (in particular) actually sound better at around this voltage rather than the more typical 450V or so.
So a Bassman is NOT off the radar.
You will get more like 35 Watts rather than 50 Watts be some of us think they are "better" Watts.
If you give us a hint about what sort of music you like to play we can maybe recommend a circuit.
Are you a Death Metal Shreader, Classic Rock or a Folk and Blues guy?
Do you use a lot of pedals between the guitar and the amp?
I'm about to dissappear for 2 weeks but your answers will help others guide you.
For your possible interest here is a "Junkbox Trainwreck" I built out of an old Philips PA Amp where the B+ was 380V. It is drop dead gorgeous. You could easily sub 6L6 into this circuit. The Power amp schematic is pretty "generic" and could be used as is with 6L6 and your existing output tranny. The preamp is the classic Trainwreck Express with a parallel input tube modification of my own design. It takes pedals fairly well. The chassis has enough tube sockets to do a really High Gain preamp if you wanted but if this is to be your firsst build I would probably advise against it, the more complicated the circuit you select then the more things that can go wrong and the harder it maybe to set to work.
Cheers,
Ian
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Much appreciated, Gingertube. I'm a classic rock guy. I'm looking for thick cleans and good classic rock crunch. Think Allman Brothers, James Gang. Not looking to shred, not looking for a "high gain" sound.
I have no problem coming out with 35 watts instead of 50, if a Bassman is the right circuit to build. This is not my first build, but it's an important one -- it's an exercise to learn what I can do with the parts I've got and WHY. If I can get my (thick) head around understanding how the parameters here can be manipulated, then I'll be a lot farther down the road of being able to spec out the parts I need to make any amp I want, and then fine tune it. That's the goal I'm working toward.
I have no problem coming out with 35 watts instead of 50, if a Bassman is the right circuit to build. This is not my first build, but it's an important one -- it's an exercise to learn what I can do with the parts I've got and WHY. If I can get my (thick) head around understanding how the parameters here can be manipulated, then I'll be a lot farther down the road of being able to spec out the parts I need to make any amp I want, and then fine tune it. That's the goal I'm working toward.
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