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#11
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Re: JE EL34 Build
You probably don't need a heat sink at your current, but the casings would still be live.
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Philip. Everything in this post is my honest opinion based on what i thought I knew at that very moment in time. |
#12
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Re: JE EL34 Build
Quote:
yep when I build my 12B4A headphone amp it have standard 1Ns Diodes on it which at time I change out for the TO220 type Mur 820 I think fast recovery which sound much better tighter faster sound the poor man’s hexfred but when I did these there were a different make and the schematic for the U8100E was confusing me but sorted now thanks for the offer
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The Blues man Turntable Rega 3 custom RB250 with ortofon 2M Blue /other goldring 1042 /WD phono2 /WD CF pre custom converted /WD psu2 /home built JE Labs Single Ended 6SL7/KT66/Speakers Frugal horns Mk1s Other turntables AR EB101/Thorns TD150mk2/Thorns TD160mk2 If you have trouble reading my posts its because I am a dyslexic member |
#14
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Re: JE EL34 Build
Quote:
Ah Yes that’s what I was trying to visualise them as but i was getting Anode and cathode mixed up the live taps will be insulated in some way PS thanks for the software tip as well Cheers
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The Blues man Turntable Rega 3 custom RB250 with ortofon 2M Blue /other goldring 1042 /WD phono2 /WD CF pre custom converted /WD psu2 /home built JE Labs Single Ended 6SL7/KT66/Speakers Frugal horns Mk1s Other turntables AR EB101/Thorns TD150mk2/Thorns TD160mk2 If you have trouble reading my posts its because I am a dyslexic member Last edited by colin.hepburn; 16th April 2011 at 01:50 PM. Reason: added text corrected spelling |
#15
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Re: JE EL34 Build
Hi All
Well its be some time now but this stalled Build is moving again got the PSU build and working first time Required HT is 380volts @ 67mA got 378volts in Duncan’s PSU Checking the psu with DMM no load I get a HT of 518volts is this about right or to high for no load
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The Blues man Turntable Rega 3 custom RB250 with ortofon 2M Blue /other goldring 1042 /WD phono2 /WD CF pre custom converted /WD psu2 /home built JE Labs Single Ended 6SL7/KT66/Speakers Frugal horns Mk1s Other turntables AR EB101/Thorns TD150mk2/Thorns TD160mk2 If you have trouble reading my posts its because I am a dyslexic member |
#16
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Re: JE EL34 Build
On the Duncans simulation, try reducing the load to a lower current (ma) and see how the voltage increases. That should give you an idea.
And (or) work out what the load is in resistance terms (ohms law) and put a resistor across the PSU to simulate the amp load and see what the voltage comes down to. Should be about 5K6 ohms (5.6K) and minimum of 25W.
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Philip. Everything in this post is my honest opinion based on what i thought I knew at that very moment in time. |
#17
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Re: JE EL34 Build
Hi Philip
Making thinks difficult well yes many have said this in the past just the way I am I guess I just thought that 518 volts was I bit high for no load HT with caps of 450volts volts not sure what the formula is to work out no load voltages The Diodes I just used two diodes making a full wave rec the diode are Mur 8100E/1000volt 8 amp fast recovery easier to use two than working with four single T0220 type diodes Part two The Amp Build will start to day
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The Blues man Turntable Rega 3 custom RB250 with ortofon 2M Blue /other goldring 1042 /WD phono2 /WD CF pre custom converted /WD psu2 /home built JE Labs Single Ended 6SL7/KT66/Speakers Frugal horns Mk1s Other turntables AR EB101/Thorns TD150mk2/Thorns TD160mk2 If you have trouble reading my posts its because I am a dyslexic member |
#18
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Re: JE EL34 Build
Hi Colin, there isn't really an easy way to calculate working voltage as it will depend on your mains TX rating and regulation. The no-load figure is in the ballpark and can be handled by the EL34s so I'd just connect psu to both amp channels now and see how it drops if the 450V caps are still ok. If you do decide to keep it the caps will need uprating voltage-wise as they will be hit by overvoltage at cold switch on and will probably fail eventually. Does your mains TX have the heater windings for a valve rect btw? If so a valve rect would might be the answer and will drop typically 60v. That with the load across the choke and on the TX may be about right.
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#19
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Re: JE EL34 Build
Hi Richard
Thanks for your reply yep the TX has 5 volt for tube rec but its only 2.5 amps my Tube rec draws 3amps I think so used the solid-state diode as I thought it was easier the 450 volt caps are still OK for now
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The Blues man Turntable Rega 3 custom RB250 with ortofon 2M Blue /other goldring 1042 /WD phono2 /WD CF pre custom converted /WD psu2 /home built JE Labs Single Ended 6SL7/KT66/Speakers Frugal horns Mk1s Other turntables AR EB101/Thorns TD150mk2/Thorns TD160mk2 If you have trouble reading my posts its because I am a dyslexic member |
#20
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Re: JE EL34 Build
Hi Colin, GZ34 1.9A, indirect too so it would turn on more slowly
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