I guess the PS really isn't that bad...
I found the IC data sheet here and it lookds easy to use- just 3-pins. I must ask, though, What do I do with the pot on the IC? Max it out? Will I have to adjust it? (I have no tools for this...)
And for me, the Digi-Key site is down, and I was using that site to find transformers... but it isn't working so I wonder if I could find an affordable 115-0-115 with a 9V heater...
Just out of curiosity, isn't 150VDC a little low for a tube amp? Most I see are 200+, so it seems low.
I found the IC data sheet here and it lookds easy to use- just 3-pins. I must ask, though, What do I do with the pot on the IC? Max it out? Will I have to adjust it? (I have no tools for this...)
And for me, the Digi-Key site is down, and I was using that site to find transformers... but it isn't working so I wonder if I could find an affordable 115-0-115 with a 9V heater...
Just out of curiosity, isn't 150VDC a little low for a tube amp? Most I see are 200+, so it seems low.
Site down?
Hi,
I need to check this but it wouldn't suprise me if they're live again tomorrow.
Yes...you'll need a DVM or ask a local electrician to adjust it for you so it puts out 6 to 6.3 VDC.
A DVM doesn't cost an arm and a leg though and if you're planning to build more in the near future it will pay for itself.
It's a pretty common B+ for the 6AS7G and the 6DJ8.
Cheers,
Hi,
I need to check this but it wouldn't suprise me if they're live again tomorrow.
Yes...you'll need a DVM or ask a local electrician to adjust it for you so it puts out 6 to 6.3 VDC.
A DVM doesn't cost an arm and a leg though and if you're planning to build more in the near future it will pay for itself.
It's a pretty common B+ for the 6AS7G and the 6DJ8.
Cheers,
All in all, is Joels preamp/headphone amp good? Would it be as good as the best of the others? Joel's seems to appeal to me more than the others...
I just found all the pinouts and put them on the schems... but I am unsure about the heater config. For the tubes used, which gets the positive and which the negative?
I just found all the pinouts and put them on the schems... but I am unsure about the heater config. For the tubes used, which gets the positive and which the negative?
Well, could the power supply of Joel's amp be used with the Waarde 6AS7G amp? Obviously with some mod to the voltage... though I don't know how to do it. 
I like the idea of tube rectified instead of solid state... but what would be the drawbacks of using Joel's PS? Do I need something on the heater area, or can I leave it with only the resistors?
EDIT: Ok, I just played with Ohm's Law a tad... not really sure what I am doing, but I got an answer for my question, would just like to check it with you guys since I have no clue what I am doing.
I am using Joel's PS, so I took the resistance (1K ohms) and .125A for the output of the tube (I think that is what it was...), so I get a 125V drop. I add this to the 285V final and get 410V, which is the voltage after the rectifier tube, and it is 600V before it. So that would mean a voltage drop of 190V across the tube. Then, I took the 410V, subtracted the 150V I need from it, and got 260V. So, I put the 260V into Ohm's Law again with the .125A current and I get a total resistance of 2080 ohms. SO this would mean that two 1040 ohm resistors in place of the 500 ohm resistors would give me the +150VDC, right? Did I totally mess that up?
I like the idea of tube rectified instead of solid state... but what would be the drawbacks of using Joel's PS? Do I need something on the heater area, or can I leave it with only the resistors?EDIT: Ok, I just played with Ohm's Law a tad... not really sure what I am doing, but I got an answer for my question, would just like to check it with you guys since I have no clue what I am doing.
I am using Joel's PS, so I took the resistance (1K ohms) and .125A for the output of the tube (I think that is what it was...), so I get a 125V drop. I add this to the 285V final and get 410V, which is the voltage after the rectifier tube, and it is 600V before it. So that would mean a voltage drop of 190V across the tube. Then, I took the 410V, subtracted the 150V I need from it, and got 260V. So, I put the 260V into Ohm's Law again with the .125A current and I get a total resistance of 2080 ohms. SO this would mean that two 1040 ohm resistors in place of the 500 ohm resistors would give me the +150VDC, right? Did I totally mess that up?
Ohm's law
trespasser_guy,
Yes, you're doing fine. It's just arithmetic.
What I would say, is that you should choose your transformer voltage from the available range of transformers, then do minor changes with the resistors.
Also, from a cost point of view, choosing valves with big heater requirements will put your transformer into the next cost bracket.
As for Joel's circuits: They are OK, but not exceptional.
There are many circuits out there, thought up by people with more complex thinking processes than him or me.
Cheers,
trespasser_guy,
Yes, you're doing fine. It's just arithmetic.
What I would say, is that you should choose your transformer voltage from the available range of transformers, then do minor changes with the resistors.
Also, from a cost point of view, choosing valves with big heater requirements will put your transformer into the next cost bracket.
As for Joel's circuits: They are OK, but not exceptional.
There are many circuits out there, thought up by people with more complex thinking processes than him or me.
Cheers,
Re: Ohm's law
Absolutely.
And I wouldn't call this my circuit. The idea of paralleling two 6SN7's is not a new one! Neither is RC coupling. In fact, unless you're working in the digital world, chances are it's been done before.
As far as their exceptional-ness... simple but effective RC coupled amplifiers using work-horse tubes are NOT currently fashionable. If you showed up at an Audio Fest with one of these they'd pee on you - BUT... that doesn't mean it can't compete. I think that circuit is as neutral and well-tempered as any headphone driver I've heard over the years. Could you add a bunch of transistors in there, acheiving "better" performance? Sure. Could you use fancier tubes? Sure. What's the point? You obviously are not in the market for this type/price range of unit.
Hang on, I'm getting to the point!
a) there are no wonder tubes that guaranty performance. (see 6N1P)
b) cost does not guaranty performance.
c) high parts count does not guaranty performance.
d) adding some silicon to a circuit does not make you smart.
e) if you can't hear the difference, who cares?
f) you are not original.
Study them well.
dhaen said:
Absolutely.
And I wouldn't call this my circuit. The idea of paralleling two 6SN7's is not a new one! Neither is RC coupling. In fact, unless you're working in the digital world, chances are it's been done before.
As far as their exceptional-ness... simple but effective RC coupled amplifiers using work-horse tubes are NOT currently fashionable. If you showed up at an Audio Fest with one of these they'd pee on you - BUT... that doesn't mean it can't compete. I think that circuit is as neutral and well-tempered as any headphone driver I've heard over the years. Could you add a bunch of transistors in there, acheiving "better" performance? Sure. Could you use fancier tubes? Sure. What's the point? You obviously are not in the market for this type/price range of unit.
Hang on, I'm getting to the point!
a) there are no wonder tubes that guaranty performance. (see 6N1P)
b) cost does not guaranty performance.
c) high parts count does not guaranty performance.
d) adding some silicon to a circuit does not make you smart.
e) if you can't hear the difference, who cares?
f) you are not original.
Study them well.
Well, I just missed my edit post time by about 3 minutes...
So, I was looking at transformers. What exactly would I need for it to work best with Joel's power supply? I found some 275-0-275 @ 150mA, 250-0-250 @ 70mA, 300-0-300 @100mA, etc. What mA rating should I have? What A rating for the heater filaments? (the 5V and 6.3V) Are there any other transformers I am not seeing that would be able to give me a closer voltage to what I need? I need about 240-0-240 in order to get me close to the 150VDC I need for the amp, after the voltage drop across the rectifier.
So, I was looking at transformers. What exactly would I need for it to work best with Joel's power supply? I found some 275-0-275 @ 150mA, 250-0-250 @ 70mA, 300-0-300 @100mA, etc. What mA rating should I have? What A rating for the heater filaments? (the 5V and 6.3V) Are there any other transformers I am not seeing that would be able to give me a closer voltage to what I need? I need about 240-0-240 in order to get me close to the 150VDC I need for the amp, after the voltage drop across the rectifier.
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