The "$250" Amp? - 6LU8 Compactron SE, UL
- Thread starter Wigwam Jones
- Start date
vinylkid58
Super Member
I just need to get a 6v toroid to supply the 6BY5GA's that I have. Or, I could just get two AN-3T275's and build mono-blocks. I'd still be way under budget compared to buying one Hammond 370HX @ $138.97.:scratch2:
Congratulations on your build BTW.:thmbsp:
Jeff
Kegger
R.I.P. 1/12/1966 - 6/1/2017
From what's been posted about the Antek tranny yu should be fine doing stereo PP amp.
With (2) 6.3v windings at 5A each you have room for (4) 6LU8 then using (2) 6BY5/6DE4
damper diodes for your tubed rectification, either type of rectifier would be fine for a amp.
With (2) 6.3v windings at 5A each you have room for (4) 6LU8 then using (2) 6BY5/6DE4
damper diodes for your tubed rectification, either type of rectifier would be fine for a amp.
vinylkid58
Super Member
I based my assumptions on the 4A ratings shown on the pdf file from the AnTek site. Do you consider this rating to be conservative?
I thought the amp might sound better with a separate heater trans. for the rectifiers.:headscrat
Jeff
Kegger
R.I.P. 1/12/1966 - 6/1/2017
I believe the 4a and 2a was for when it had the 6.3v winding and that 12.6v winding.
(the original we had was 6.3v at 5a an 6.3v at 5a, I didn't think they dropped it now)
I don't have the tranny, I'm going off what others have posted here and at DIYAUDIO.
(I also don't think it said on the tranny what the currents were, but what was stated)
Both 6.3v windings come from the same core and should have the same ratings there.
(the original we had was 6.3v at 5a an 6.3v at 5a, I didn't think they dropped it now)
I don't have the tranny, I'm going off what others have posted here and at DIYAUDIO.
(I also don't think it said on the tranny what the currents were, but what was stated)
Both 6.3v windings come from the same core and should have the same ratings there.
GOYA
Super Member
From the sticker on the 3T-275 Antek I received, it has 275V X2, 6.3V 4A and 6.3V 2A.
Thanks, I haven't used any of my other amps since I got it running.
Thanks, I haven't used any of my other amps since I got it running.
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Kegger
R.I.P. 1/12/1966 - 6/1/2017
You are correct you go so far with the cap an the voltage won't increase anymore.
Somewhere around that 15uf (total) mark will be the extent of it, now 278 isn't bad
voltage an will work just fine, my assumption is you have low wall voltage, could be
the rectifier your using has a slightly lower output an another may get you higher.
(the 6BY5 does give less voltage than the EZ81 does as well)
But overall with around 15uf cap on the input an 278v will be just fine, an work well.
Somewhere around that 15uf (total) mark will be the extent of it, now 278 isn't bad
voltage an will work just fine, my assumption is you have low wall voltage, could be
the rectifier your using has a slightly lower output an another may get you higher.
(the 6BY5 does give less voltage than the EZ81 does as well)
But overall with around 15uf cap on the input an 278v will be just fine, an work well.
GOYA
Super Member
Well, I am perplexed.
I switched rectifiers to a different GE 6BY5GA, let it play for several hours and measured again. Instead of the original 249/250V reading with the 7uF filter cap, now I'm getting 242/243V. So I switch back to the original rectifier and the readings are still 242/243V. Even increasing the filter cap to 19uF I still can't reach 270V. Any idea what may have happened?
BTW, my house voltage is 114/115V.
I switched rectifiers to a different GE 6BY5GA, let it play for several hours and measured again. Instead of the original 249/250V reading with the 7uF filter cap, now I'm getting 242/243V. So I switch back to the original rectifier and the readings are still 242/243V. Even increasing the filter cap to 19uF I still can't reach 270V. Any idea what may have happened?
BTW, my house voltage is 114/115V.
Kegger
R.I.P. 1/12/1966 - 6/1/2017
I suspect it would be 1 of 2 things or a combo of both.
With a low wall voltage like you mention you'd get a low output, around here were about
122v most of the time, that will certainly make a difference, second could be your meter
either having low battery (I've been duped by that before) or is just not reading correct.
In some areas wall voltage fluctuates quite a bit, so is possible your in a down time now.
(may want to monitor your wall voltage)
Suggest try new batteries in the meter an getting second reading with a different meter.
(it may sound off, but I've had plenty of screwed up meter readings in the past here to)
After confirming meter an still having the issue if you have a variac you can crank up the
AC voltage with it to get a little more then you put in, if so try 122v an see what yu get.
If it does turn out to be wall voltage and your looking for a fix a computer UPS can work.
(I've got 1 that can take anywhere from 110v - 135v on input an output a steady 120v)
With a low wall voltage like you mention you'd get a low output, around here were about
122v most of the time, that will certainly make a difference, second could be your meter
either having low battery (I've been duped by that before) or is just not reading correct.
In some areas wall voltage fluctuates quite a bit, so is possible your in a down time now.
(may want to monitor your wall voltage)
Suggest try new batteries in the meter an getting second reading with a different meter.
(it may sound off, but I've had plenty of screwed up meter readings in the past here to)
After confirming meter an still having the issue if you have a variac you can crank up the
AC voltage with it to get a little more then you put in, if so try 122v an see what yu get.
If it does turn out to be wall voltage and your looking for a fix a computer UPS can work.
(I've got 1 that can take anywhere from 110v - 135v on input an output a steady 120v)
GOYA
Super Member
The battery in the DMM is strong. I replaced with a new battery and the readings are the same. I just learned that the fuse in my old analog VOM is open.
I don't have a variac but isn't it a given that with higher wall voltage I'd get higher voltage in the amp? The bottom line is that I have 115V. Is there another rectifier I could use to get where I need to be? Maybe two 6AU4?
edit, nevermind about the 6AU4s. I don't have heater current for them.
Maybe go to the EZ81? Seems I had problems with it in PSU2 but it seems to sim OK now.
I don't have a variac but isn't it a given that with higher wall voltage I'd get higher voltage in the amp? The bottom line is that I have 115V. Is there another rectifier I could use to get where I need to be? Maybe two 6AU4?
edit, nevermind about the 6AU4s. I don't have heater current for them.
Maybe go to the EZ81? Seems I had problems with it in PSU2 but it seems to sim OK now.
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Kegger
R.I.P. 1/12/1966 - 6/1/2017
My reason for making the variac comment was to see if you got 122v input that yu
did actually get the 300v dc output to see that nothing screwey was going on here.
(I now know you don't have the variac but that was my reason for suggesting it)
Your low wall voltage is something I have not heard of either, I hadn't seen anyone
in a while with voltage less then say 118v ac from the wall, you may want to make
a call to your electricity provider an have them inspect.
--------------------------------------------------------------------------------
(As far as modding the amp)
Myself I'd treat both 6.3v windings at least rated for 4a ea., coming from same core.
Now there is the 6W4 damper diode, (all octals same pinout) at 1.2a per diode there.
The 6W4 is cheap and plentiful, a pair of these with a 20uf cap input will move yu up.
After doing something like that an if your not quite where you want to be the second
choke can be replaced with say a 75ohm big ole wirewound resistor to get more volts.
I wouldn't want to use the resistor with that small cap input, but if using say 20uf on
the input then the second or third filter being an RC network wouldn't be to bad here.
did actually get the 300v dc output to see that nothing screwey was going on here.
(I now know you don't have the variac but that was my reason for suggesting it)
Your low wall voltage is something I have not heard of either, I hadn't seen anyone
in a while with voltage less then say 118v ac from the wall, you may want to make
a call to your electricity provider an have them inspect.
--------------------------------------------------------------------------------
(As far as modding the amp)
Myself I'd treat both 6.3v windings at least rated for 4a ea., coming from same core.
Now there is the 6W4 damper diode, (all octals same pinout) at 1.2a per diode there.
The 6W4 is cheap and plentiful, a pair of these with a 20uf cap input will move yu up.
After doing something like that an if your not quite where you want to be the second
choke can be replaced with say a 75ohm big ole wirewound resistor to get more volts.
I wouldn't want to use the resistor with that small cap input, but if using say 20uf on
the input then the second or third filter being an RC network wouldn't be to bad here.
vinylkid58
Super Member
dnewma04
The Healer
Otherwise you always have SS diodes for more voltage an do away with the tubes..
:thmbsp:
GOYA
Super Member
Negative. Can I get a good measurement with it in circuit?
edit: maybe pull the rectifier?
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vinylkid58
Super Member
Try it both ways. There is the remote possibility that the AnTek isn't producing it's rated output.
Jeff