Hey all,
was interested in building a medium-powered bass head using only 2 807s in push-pull with about 600V on the plates. i recall having read somewhere that it was possible to get 100W (continuous) from them without a problem....
does anyone have any experience with this tube, or how much power one can actually get out of it? the datasheet specifices 80W Pout in class AB2.
807 push pull?
Moderators: pompeiisneaks, Colossal
807 push pull?
In the interest of full disclosure, I am Animal Factory Amplification.
Re: 807 push pull?
The 807 is excellent but isn't the best choice for high power MI applications.
A pair can deliver up to 60 gracefully distorted watts in AB1 @ 600V plates / 300V screens and can go up to 120 watts max in AB2 @ 750V plates / 300V screens. These conditions are maximum ICAS - intermittent use, OK for up to say a few hours at a time but I wouldn't trust such an amp for heavy stage use.
Grids will draw current in AB2, you'll have to use driver tubes or a transformer after the PI. A very tight - read regulated - screen supply is mandatory if you fancy reliability.
I would stay in AB1 and use two pairs in parallel push-pull for up to 120 watts, or use another big bottle - for instance a pair of KT88's in AB1 @ 600V plates / 300V screens delivers more than 100 watts.
A pair can deliver up to 60 gracefully distorted watts in AB1 @ 600V plates / 300V screens and can go up to 120 watts max in AB2 @ 750V plates / 300V screens. These conditions are maximum ICAS - intermittent use, OK for up to say a few hours at a time but I wouldn't trust such an amp for heavy stage use.
Grids will draw current in AB2, you'll have to use driver tubes or a transformer after the PI. A very tight - read regulated - screen supply is mandatory if you fancy reliability.
I would stay in AB1 and use two pairs in parallel push-pull for up to 120 watts, or use another big bottle - for instance a pair of KT88's in AB1 @ 600V plates / 300V screens delivers more than 100 watts.
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skyboltone
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Re: 807 push pull?
For Bass use you could jump to the 811. It's a triode but you don't need separate screen supply and I doubt you'll need all that much distortion for bass. They take about 1250VDC (from memory) or more. You should be able to get LOTS of power. If you want me to look it up in the transmitting tubes book and send you the data let me know.
Also, I have and 800CT at 1 amp transformer that will work good in a bridge rectifier that will power it.
The OT will cost an arm and a leg though. Phil at Heyboer will be happy to wind one for you.
As FYL said thoug you need a driver tube. Frequently they used 807s for that.
Pretty oddball set up for stage use. Why not go with an Alembic pre and a solid state 400 watt amp from Crown or something. Or keep an eye out for an ampeg I forgot the model number. 6 ea KT-88 types. They show up on Ebay once an awhile for not too much money
Also, I have and 800CT at 1 amp transformer that will work good in a bridge rectifier that will power it.
The OT will cost an arm and a leg though. Phil at Heyboer will be happy to wind one for you.
As FYL said thoug you need a driver tube. Frequently they used 807s for that.
Pretty oddball set up for stage use. Why not go with an Alembic pre and a solid state 400 watt amp from Crown or something. Or keep an eye out for an ampeg I forgot the model number. 6 ea KT-88 types. They show up on Ebay once an awhile for not too much money
The Last of the World's Great Human Beings
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
Re: 807 push pull?
thanks all, it just happens that i have a pair (actually, three) NOS JAN 807s and have no idea what to do with them. apparently, they're quite well-loved on the audiophile circuit, but i thought it would be a shame to "waste" them for SE operation in triode mode...
for bass, i'm going to eventually DIY a mesa bass 400 with 6x 6L6s... was just wondering if i could use these isntead, only home use though. i just wanted higher wattages for better headroom and low end response at low volumes.... all speculation, basically.
it'll probably actually end up being a solid state amp for a while. i was just curious as to what was possible and how much was pushing the envelope...
for bass, i'm going to eventually DIY a mesa bass 400 with 6x 6L6s... was just wondering if i could use these isntead, only home use though. i just wanted higher wattages for better headroom and low end response at low volumes.... all speculation, basically.
it'll probably actually end up being a solid state amp for a while. i was just curious as to what was possible and how much was pushing the envelope...
In the interest of full disclosure, I am Animal Factory Amplification.
-
skyboltone
- Posts: 2287
- Joined: Wed May 10, 2006 7:02 pm
- Location: Sparks, NV, where nowhere looks like home.
Re: 807 push pull?
Well Flood;
You could do it, and the audio files don't run them with separate screen voltage supplys. Indeed Bob Crooks who was Standel amps used 807s (very well loved in country circles) didn't use a separate screen supply. Just a screen resistor like we do all the time. But he only designed for 25 watts. I don't know for sure but I imagine his plate voltage was around 300 volts anyway.
If you run them ultra linear with 40% taps you could go to 600 volts and get some serious power. NOS (jan) 807 only go for about $20 a pair on Ebay. So what if you melt them down. Have Phil (Heyboer)give you 40% and 50% taps and see what happen. Most of us don't like UL for guitar but bass is different.
Why don't you learn how to work from a set of curves? The best explanation I've seen is in the RCA tube manuals both the receiving manual and the transmitting manual. The 807 was designed to replace the 6L6G for higher frequency transmitting use. So you can use the 6L6 family of curves and see what you're up against. All you need is to scan the curve family drawing into you computer. Open it in MS Photo Manager and enlarge it to print full page. Get a ruler and a pencil and you can design your own power section. If it were me I'd just use a Showman pre and off to the races.
The late Ted Weber's site has a schematic of his quess on a Standel design. They were going to make them but when Ted passed the family more or less put it on perminant hold. I just went there but couldn't find it because I'm not registered. You could register or call them for the web address of the scheme. They are not touchy about that.
You could do it, and the audio files don't run them with separate screen voltage supplys. Indeed Bob Crooks who was Standel amps used 807s (very well loved in country circles) didn't use a separate screen supply. Just a screen resistor like we do all the time. But he only designed for 25 watts. I don't know for sure but I imagine his plate voltage was around 300 volts anyway.
If you run them ultra linear with 40% taps you could go to 600 volts and get some serious power. NOS (jan) 807 only go for about $20 a pair on Ebay. So what if you melt them down. Have Phil (Heyboer)give you 40% and 50% taps and see what happen. Most of us don't like UL for guitar but bass is different.
Why don't you learn how to work from a set of curves? The best explanation I've seen is in the RCA tube manuals both the receiving manual and the transmitting manual. The 807 was designed to replace the 6L6G for higher frequency transmitting use. So you can use the 6L6 family of curves and see what you're up against. All you need is to scan the curve family drawing into you computer. Open it in MS Photo Manager and enlarge it to print full page. Get a ruler and a pencil and you can design your own power section. If it were me I'd just use a Showman pre and off to the races.
The late Ted Weber's site has a schematic of his quess on a Standel design. They were going to make them but when Ted passed the family more or less put it on perminant hold. I just went there but couldn't find it because I'm not registered. You could register or call them for the web address of the scheme. They are not touchy about that.
The Last of the World's Great Human Beings
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.
Seek immediate medical attention if you suddenly go either deaf or blind.
If you put the Federal Government in charge of the Sahara Desert, in five years time there would be a shortage of sand.