I just ordered my kit from Glassware, I went with all four 6CG7 tubes for now, and ordered all the parts I could from him.
Which leaves a selector switch, volume pot, PSU and chassis. Any recommendations here?
I've built a DAC but this is my first tube amp project so I'll likely have some noob questions.
Which leaves a selector switch, volume pot, PSU and chassis. Any recommendations here?
I've built a DAC but this is my first tube amp project so I'll likely have some noob questions.
As a first time tube project, you may struggle a little bit. He does not do much hand holding on parts selection and assumes the builder has some theory behind them. That being said they are very well thought out designs and nice quality boards. I just purchased the octal version and the tetra sans ps phono board. Since it includes the power supply in the main pc board all you need for power supply is transformer, one for high voltage and one for filaments. Your volume control and selector will first depend if you want manual switches ore something a little more fancy. I think when he gets them back in stock I will go with his solution for volume, selector, and power they have simple elegance to them. As far as case work first you will decide if you want the tubes exposed on top or enclosed and build the board appropriately.Tube cases seem to lend themselves to nice wooden boxes, not much material used so some nice exotic woods won't break the bank if you have the tools. My last tube projects I had the top plates laser cut from polished stainless steel saved a lot of grief and came out looking good.
Bill
Bill
I have not decided yet, since I am powering the tetra san ps from the all in one board I will need to use 12v filament transformer. Most of the Hammond's with multiple taps support 6v for filaments but I have not looked over the entire line. I have so many projects ahead of this one I probably won't start collecting parts for a while. It will give me a little opportunity to bone up on theory and approach this with a little more insight.
Bill
Bill
Attachments
Here's my Aikido Octal to give you some ideas:
An externally hosted image should be here but it was not working when we last tested it.
I would recommend finding a pair of 10,000uf 20V capacitors for the heater supply smoothing.
12.6*1.414=17V and the kit comes with 16V heater supply caps.
I am in the process of getting some caps from Digikey.
The 16V may be fine but I didn't want to push it.
I set my heater supply up for 12.6V and then used the heater jumpers to set the valves in two series pair for 6.3V to each heater.
I figured this would give me the best selection down the road if I want to roll tubes.
Check out my thread here on my Aikido build there is a lot of good info.
Send me a PM if you would like to call me and pick my brain.
I used Obbligato Gold for the output caps on mine.
12.6*1.414=17V and the kit comes with 16V heater supply caps.
I am in the process of getting some caps from Digikey.
The 16V may be fine but I didn't want to push it.
I set my heater supply up for 12.6V and then used the heater jumpers to set the valves in two series pair for 6.3V to each heater.
I figured this would give me the best selection down the road if I want to roll tubes.
Check out my thread here on my Aikido build there is a lot of good info.
Send me a PM if you would like to call me and pick my brain.
I used Obbligato Gold for the output caps on mine.
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Sweet! You guys didn't get any noise from the toroidials then? Evanc, that's a gorgeous case, very similar to what I've got in mind. I have a much stronger background in woodworking than electronics, and my speakers are all cherry. Looks as though I don't necessarily need to solder on the backside to get the tubes to stand out.
Evanc, so the PSU that comes with the kit steps down the transformer to 6.5? I was thinking I'd need to get one already configured that way, like the Hammonds.
Migkiller, does that wood top board get too hot? I've got a killer piece of figured maple but was thinking I'd need to make that top plate metal.
Evanc, so the PSU that comes with the kit steps down the transformer to 6.5? I was thinking I'd need to get one already configured that way, like the Hammonds.
Migkiller, does that wood top board get too hot? I've got a killer piece of figured maple but was thinking I'd need to make that top plate metal.
The tubes and regulator are on the front of the board, and the rest of the parts are on the back. I had trouble with the heater voltage. after the regulator drop I was a little below 6 volts. The amp worked fine like this. Eventually I went to 8cg7 tubes, a lot cheaper then 6cg7. I installed a separate 12 volt transformer for the heater supply.
My tube amp uses a wooden top plate and it is OK. I milled the wood to about 3/16" thick. I built the Aikido and the amp on the top plate and then slipped the plate into the case from the bottom up to a lip at the top and held it up with some blocks screwed to the case.
My tube amp uses a wooden top plate and it is OK. I milled the wood to about 3/16" thick. I built the Aikido and the amp on the top plate and then slipped the plate into the case from the bottom up to a lip at the top and held it up with some blocks screwed to the case.
its adjustable
R24, from where Im looking
bigger resistor = higher voltage
if too big(high), you can adjust it down with a paralel resistor
I think the tolerance would be +/-0.3V
so it shouldnt be below 6V
that is, if your meter measures correct
at very low voltage you are a bit low on 'free' voltage to waste, thus AC slightly higher than the regulated DC
at high voltage it might be the opposite way round, giving too much DC voltage for the reg to handle
regulator spec sheet should tell this
but hey, Im no expert
ok, went back to study again
you get a 2V voltage drop on the 4x rectifer full-wave bridge setup
the 2V drop remains the same for all voltages
thus a very large percentage at very low voltage
the other alternative configuration, with a center tapped trafo and 2 rectifers, have lower 1V voltage drop
hope this was a bit more clever
you get a 2V voltage drop on the 4x rectifer full-wave bridge setup
the 2V drop remains the same for all voltages
thus a very large percentage at very low voltage
the other alternative configuration, with a center tapped trafo and 2 rectifers, have lower 1V voltage drop
hope this was a bit more clever
well, there are a few annoying things with the manual
on-board heater supply smoothing cap numbers on schematic shown in manual appears not to match the numbers used on actual kit/print board
manual is obviously a kind of one-for-all, with small changes
its ok tho, but could confuse a bit
and there is not a proper schematic of the complete onboard supply
I find that very annoying
but nothings ever perfect I guess
probably still a far better manual than you would find elsewhere
I would aim more directly at a totally 'general' manual
and then supply all the actual individual specific kit info added in loose paper form
well, I will be still and shut up, for now
on-board heater supply smoothing cap numbers on schematic shown in manual appears not to match the numbers used on actual kit/print board
manual is obviously a kind of one-for-all, with small changes
its ok tho, but could confuse a bit
and there is not a proper schematic of the complete onboard supply
I find that very annoying
but nothings ever perfect I guess
probably still a far better manual than you would find elsewhere
I would aim more directly at a totally 'general' manual
and then supply all the actual individual specific kit info added in loose paper form
well, I will be still and shut up, for now
Not at all, I drilled holes on the bottom. I think i paid 20 bucks shipped for the case.
you'll have to take in consideration a couple of things.
one, Tom is having board manufacturing issues, he's swapped boards makers a few times after the manual is printed.
and second, when Tom prototyped these designs, he used a motorcycle battery as the heater supply. the little bit of under voltage is OK, its the ground referencing that has to be tweaked for the tube type used.
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