ECC99 max plate dissipation is 5W per triode... So a push-pull pair would probably yield no more than 2W output.
JJ says, "power stage little P-P triode amplifiers (10W-4xECC99)." I guess they're claiming 10 watts from four triode sections paralleled.
http://www.jj-electronic.sk/pdf/ECC99.pdf
Wait... That's 20W plate dissipation to get 10W audio power output. When was the last time you saw a Class A triode amp that could run with 50% efficiency? More like 20%, usually. That would be more like 5W per channel in real life. Maybe 8 watts Class AB1?
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JJ says, "power stage little P-P triode amplifiers (10W-4xECC99)." I guess they're claiming 10 watts from four triode sections paralleled.
http://www.jj-electronic.sk/pdf/ECC99.pdf
Wait... That's 20W plate dissipation to get 10W audio power output. When was the last time you saw a Class A triode amp that could run with 50% efficiency? More like 20%, usually. That would be more like 5W per channel in real life. Maybe 8 watts Class AB1?
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I played with it years ago when Steve published the idea. Drive voltage is inversely related to tube Mu, so you want the lowest Mu possible. I had buckets full of used and dirty 6AS7G's.
With a Mu of 2, that's what I used. It makes a nice sounding low powered amp, and a good way to melt control grids. When you melt the grid in a 6AS7, there is a chance that the glowing grid wire will short to something when it melts.....sometimes that something is the plate, which eats the mosfet driver.
I tinkered with paralleled output tube years ago as well. A dozen or so 6AQ5's works about as well as a pair of 6L6GC's, so I tossed the 6AQ5 breadboard.
That's news to me and a whole lot of the SET guys. So far my favorite is a triode wired 7403, but these guys are scarce. A pair can make 70 watts. Triode wired 6550's will make 40 or so watts and run without the need for any feedback, sound good too. One of my favorite amps was a P-P 300B amp that made about 25 WPC.......
I wonder how many tubes I need to parallel to make a "300B." I have a bunch of 5687's and 7044's......let's see 5 per side, 10 per channel should work?????
It you are even thinking about it, don't waste your time with 12AU7's. I would think 6SN7, 6BL7 or 6BX7, but I don't have lots of these.
Just a parantesis, I started a thread in a Swedish forum about a project I wanted to try - 6SN7PSE.
Some schematics and answers together with redesigns to be found here:
HiFiForum.nu - En SNeseglare tar form (slutsteg med förstegsrör)
There are also some ideas for Russian 6N6P and E88CC.
Some schematics and answers together with redesigns to be found here:
HiFiForum.nu - En SNeseglare tar form (slutsteg med förstegsrör)
There are also some ideas for Russian 6N6P and E88CC.
I've got speakers with 87dB/V sensitivity, and I personally don't need more than a watt of power.
I've done balanced outputs with 6SN7, 2C22, 6E5P, 6N3P and a bunch of other 'preamp' tubes. Tiny and pretty 6N16 made about 0.2 W, and it was very good for normal listening with speakers. Maybe not for parties; but 0.7 W covers all my party needs, and 1 W exceeds them.
Depends on what kind of power you need. My opinion is that most people don't really need all that much power to begin with. Some do. But if you go low power, you absolutely must make sure you have first class transient response. Most traditional topologies will sound pretty bad low power.
I've done balanced outputs with 6SN7, 2C22, 6E5P, 6N3P and a bunch of other 'preamp' tubes. Tiny and pretty 6N16 made about 0.2 W, and it was very good for normal listening with speakers. Maybe not for parties; but 0.7 W covers all my party needs, and 1 W exceeds them.
Depends on what kind of power you need. My opinion is that most people don't really need all that much power to begin with. Some do. But if you go low power, you absolutely must make sure you have first class transient response. Most traditional topologies will sound pretty bad low power.
Hey Sheldon, maybe if you post a proposed schematic? I googled it and it gave me this thread as the first hit.
Re: Speaker sensitivity and power --
'Normal' listening levels vary widely between listeners.
Member Pano has a thread in the multi-way speaker forum where he gives a method for finding how much power output you actually need from an amp. The basic idea is that you play music at as loud a level as you would ever use, and take note of the position of your volume control. Leave the volume setting right there. You then play a digital file recorded at a specific level (I think it's -12dBFS, but I'd have to check to make sure) and measure the voltage present across your speaker terminals while that file is playing. A little easy math and you now know what RMS voltage you need to play your music at your loudest setting, with a little bit of headroom.
I have 90dB/1W speakers. I did the test and found that I need 15W per channel. My amp delivers 6W per channel, and I find that it sounds fine. That means I'm likely driving it into clipping on peaks, but only when I'm listening, er... 'exuberantly.'
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Re: Speaker sensitivity and power --
'Normal' listening levels vary widely between listeners.
Member Pano has a thread in the multi-way speaker forum where he gives a method for finding how much power output you actually need from an amp. The basic idea is that you play music at as loud a level as you would ever use, and take note of the position of your volume control. Leave the volume setting right there. You then play a digital file recorded at a specific level (I think it's -12dBFS, but I'd have to check to make sure) and measure the voltage present across your speaker terminals while that file is playing. A little easy math and you now know what RMS voltage you need to play your music at your loudest setting, with a little bit of headroom.
I have 90dB/1W speakers. I did the test and found that I need 15W per channel. My amp delivers 6W per channel, and I find that it sounds fine. That means I'm likely driving it into clipping on peaks, but only when I'm listening, er... 'exuberantly.'
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