| wuffer |
i was thinking if it would be possible to make a regulated psu for an tube preamp..
it should have 6v 0.8a and 40v 1a.. ground is the same...
is it possible?? |
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| Brett |
| quote: | Originally posted by wuffer
i was thinking if it would be possible to make a regulated psu for an tube preamp..
it should have 6v 0.8a and 40v 1a.. ground is the same...
is it possible?? |
The heaters I understand, but 40V at 1A? Huh?
Of course you can do a regulated PS for a tube preamp. I like shunt regs best myself. |
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| amperex |
| I do not know of any tubes that operate linear at 40 volts plate. TI made a floating type 3-terminal regulator that operated up to 120 volts output @ 1 amp. |
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| wuffer |
thanks..
tubes are 6J5-GT |
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| SY |
| You'll need a minimum of 100V on the plates, which means a supply in the 200-400V range. Unless you're going to run 50 of them, you don't need anything like 1A. |
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| wuffer |
i have heard it with a normal psu with big caps and 40v and it sound good, very good :cool:
can se the transformer is 24-30v 1a and should be 32-42v after the rectifier and caps so i want the same just want to try the regulated psu instead :) |
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| wuffer |
looks like the one i want to build :cool: the bastard :cool: |
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| SvErD |
Jepp, it's the B*A*S*T*A*R*D from Ny Elektronikk. I built mine 10-12 years ago and still use it i one of my systems.
I use some old L63 tubes by the way. |
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| wuffer |
sounds good :)
i have the construction manual here and 1 pcb..
i would go after the 6J5-GT tubes.. those i can get..
what pots are you using for volume |
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| SvErD |
| I'm using a Noble 50k, but any good 50-100k pot/attenuator will be good. |
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| wuffer |
thanks im thinking of an alps 27 with motor..
back to the psu.. anyone??? |
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| wuffer |
| looks nice but im not sure how i get lower voltage out of it... |
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| SvErD |
| The string of zeners D6-8 sets the voltage |
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| wuffer |
| thanks.. i can read diagram and build from a diagram but when i shall change components and so on im lost so if there is any one that could draw a diagram i would be very gratefull |
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| SvErD |
If you use the diagram in the thread linked to above and use one 39v zener or 3 x 13v zeners you should get ~40v.
Use a 35-40v transformer. |
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| wuffer |
if i change D6-D8 with 3 zener at 13 volt i would get 39 on the output... and no other component should be changed
but the mje3439 cant i get in denmark.. :( |
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| SvErD |
| The transistor is not critical, use a BD239 f.ex. |
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| wuffer |
| thanks a lot.. i think i know enough to make the psu.. |
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| SY |
I put together a breadboard of this (used half of a 6SN7) and it is a very interesting effects box, but not even vaguely an accurate preamp. It choked when asked to swing more than 3V peak, and at that level, it had over 10% distortion. Gain of less than 2, but the distortion is so bad that it's difficult to assign a number. All of this is predictable from the datasheet curves which show the plate resistance as a function of current- it gets VERY steep at currents lower than 5mA (this circuit runs about 1.1-1.2mA). The tiny plate load means that the linearity is dominated by the plate resistance. The mu also becomes strongly nonlinear in this current and voltage range.
My generator source Z is quite low- for something fed from a potentiometer, expect the distortion to go higher since the tube is biased very near the region where grid current distortion begins.
There are tubes suitable for low voltage use. 6J5/6SN7 are not one of them. |
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| wuffer |
problem solved.. a very nice man in denmark has offer to make the psu for me :cool:
so santa claus is comming early this year :hohoho:
whatever the tube is suitable for low voltage or not i dont care.. i think it sound beautiful :D |
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