very good practice, even today i am scared stiff when powering up my freshly built tube amps for the first time, even if i know that i have done everything right.....
a lamp tester in series with the mains really comes in handy next time you decide to do it yourself...
btw, a couple of years ago i did two of these 2A3 amps, biased equally at 250volts plate and 60mA....the Shuguangs biased identically spot on...
AJT,
Greetings! Thanks for joining the thread.
If you have the time can you please take a look at George's recommendation under 2A3 Tubes on this page?
Tubes and Applications | Tubelab
The filament current for two 2A3 tubes is 5 amps. A power transformer with at least 6 Amp capability on the 6.3 volt winding is required. A center tap on the 6.3 volt winding is required. The filament regulator IC will require a supplemental heat sink with 2A3’s. I use the heat sink from an old Pentium IC.
My understanding is that he has on-board power regulation for filaments, and thus 6.3v with CT @ 6A is required for the TSE with 2A3.
The 5v low voltage transformer I suggested was for the rectifier tube (5AR4).
Appreciate your inputs on this.
Greetings! Thanks for joining the thread.
If you have the time can you please take a look at George's recommendation under 2A3 Tubes on this page?
Tubes and Applications | Tubelab
The filament current for two 2A3 tubes is 5 amps. A power transformer with at least 6 Amp capability on the 6.3 volt winding is required. A center tap on the 6.3 volt winding is required. The filament regulator IC will require a supplemental heat sink with 2A3’s. I use the heat sink from an old Pentium IC.
My understanding is that he has on-board power regulation for filaments, and thus 6.3v with CT @ 6A is required for the TSE with 2A3.
The 5v low voltage transformer I suggested was for the rectifier tube (5AR4).
Appreciate your inputs on this.
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ah, George is a very capable designer, i learned many of the things i know from him...
if you read the text, a regulator was used to convert the 6.3volts ac to dc voltage and regulated to supply the required voltage...
what i posted is that if you have a traffo with a 2.5v ac with center tap, then you can use it, the reason he used the 6.3volt is because 2.5 volt filaments are not commonplace today, in my amps, the power traffo i used was my own design although i asked another winder to build it for me...
btw, using just ac on the filaments, those amps that i built were totally hum free, those amps were used to drive horns, and any noise coming from the amp is magnified...
if you read the text, a regulator was used to convert the 6.3volts ac to dc voltage and regulated to supply the required voltage...
what i posted is that if you have a traffo with a 2.5v ac with center tap, then you can use it, the reason he used the 6.3volt is because 2.5 volt filaments are not commonplace today, in my amps, the power traffo i used was my own design although i asked another winder to build it for me...
btw, using just ac on the filaments, those amps that i built were totally hum free, those amps were used to drive horns, and any noise coming from the amp is magnified...
Cost of customization...
Will Edcor help you with changing the order? After all - items are "built to order"?
Change order on power transformer and go with this PT - has a 6.3v with CT @ 6A (but no 5v tap)
https://www.edcorusa.com/xpwr139
For the 5V tap (rectifier connection), take an additional low voltage PT:
https://www.edcorusa.com/lvp5-3-240
Will save some cost (~ US $100), add slight bit more work in wiring.
Zia
I am a bit confused
Do I get a power transformer - https://www.edcorusa.com/xpwr139
and an output transformer https://www.edcorusa.com/gxse15-8-5k
and LPV53-240 for the rectifier?
ie 3 transformers
Wayne
I am a bit confused
Do I get a power transformer - https://www.edcorusa.com/xpwr139
and an output transformer https://www.edcorusa.com/gxse15-8-5k
and LPV53-240 for the rectifier?
ie 3 transformers
Wayne
Yes, one unit
No. For 2A3 more suitable is: https://www.edcorusa.com/gxse15-8-2_5k
2 units.
Yes, LVP5-3-240 for rectifier
https://www.edcorusa.com/lvp5-3-240
1 unit
So, total 4 transformers.
1 x Power Transformer XPWR139
2 x Ouptput Transformer GXSE15-8-2.5K
1 x Low voltage power transformer LVP5-3-240
Have you also ordered the choke?
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