I have recently built the BA-3 Power Amplifier straight from the build guide, exactly as 6L6 did.
http://www.diyaudio.com/forums/pass-labs/258301-ba-3-amplifier-illustrated-build-guide.html
I used same box, I used the store Time Delay board just as he did, instead of the usual terminal block with dual CL-60 and .0033 cap.
I am wondering if it is working, or perhaps it just works very quick? I mean if I put Multimeter on output of time delay and flick switch, it hits 117-120 almost instantly, no build up. Reading about it, seems it does its work in a few milli-seconds, so maybe it is.
As I am using a 24+24 volt @ 1000VA transformer, I want to make sure this beast is doing its job!
Is this normal? I envisioned a slow build up of volts then full power. Can someone please advise?
Russellc
http://www.diyaudio.com/forums/pass-labs/258301-ba-3-amplifier-illustrated-build-guide.html
I used same box, I used the store Time Delay board just as he did, instead of the usual terminal block with dual CL-60 and .0033 cap.
I am wondering if it is working, or perhaps it just works very quick? I mean if I put Multimeter on output of time delay and flick switch, it hits 117-120 almost instantly, no build up. Reading about it, seems it does its work in a few milli-seconds, so maybe it is.
As I am using a 24+24 volt @ 1000VA transformer, I want to make sure this beast is doing its job!
Is this normal? I envisioned a slow build up of volts then full power. Can someone please advise?
Russellc
Apparently, as I have learned, It happens really fast so I guess its working fine. I just wondered, I guess I thought it would be an observable build up. When I measured the output of the board, it was basically instantaneous. Maybe I will alter the components to slow it a little, but as long as the caps are charged before the mains hit everything is OK.
Russellc
Russellc
??? You mean instead of the time delay or in addition? I thought I did it the same way you did in your build...😕 I hear the relay click on shortly after turn on, If I listen really close I hear the faintest "boing" noise as the juice hits the transformer, or it feels the cap bank...If that's what you mean I can install the CL-60 + X-1 cap thingie on a terminal block in addition, just not sure what you mean by "Use CL-60"... if in addition, before the time delay or afterwards?
Russellc
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One other question, my power supply boards (teabags) have a place for a LED and a resistor to reduce voltage to it...these were not included in the group buy for parts, is there a typical value of resistor that is used for that?
Russellc
Russellc
I actually mean instead of... The monster transformer is so big that the small delay of the soft-start isn't making much difference.
It's wouldn't hurt to set everything as slow as possible in that circuit first, perhaps that would help.
As for LED resistor, anything from about 4.7K to 10K will be fine.
It's wouldn't hurt to set everything as slow as possible in that circuit first, perhaps that would help.
As for LED resistor, anything from about 4.7K to 10K will be fine.
How about cl-60 in place of the resistors in the soft start? This coupled with a bit longer delay maybe best of both.
That wouldn't do very much... The CL-60 have a cold resistance of about 10ohm, much less than the resistors, and would still be switched out in a few ms.
exactly what I'm writing all these years - same resistance but NTC instead of fixed , longer delay and voila!
Ok, I will try altering the cap, same time I order .68 cap, I will get some more CL-60, only have CL-30 in box....
Have you used a T9A or T10A fuse for your 1000VA 115Vac transformer?
If you have and it does not blow then the soft start is working.
Without a soft start the transformer would probably need a fuse bigger than 20A, to get reliable starting from cold.
If you have and it does not blow then the soft start is working.
Without a soft start the transformer would probably need a fuse bigger than 20A, to get reliable starting from cold.
Its in the DIYstore 5U box with their back panel kit. The IEC it comes with holds two fuses, I believe I have 2.5 amp slow blo in there. They have been holding fine.
Russellc
T2.5A will allow the transformer to deliver ~270watts.
If the 1000VA starts with this very small fuse, then your soft start is very definitely working.
If the 1000VA starts with this very small fuse, then your soft start is very definitely working.
i pulled out the resistors i my softstarts (2x33ohm in series) and installed 2x CL60 in series instead. that will prevent welding of the rèley when the resistor curcuit is bypassed.
The problem i had with resistors in place was welding of the rèley, resistor burning and blowing the main fuse (16A) at allmost every startup. With CL60's they have now been working just fine for 3-4 years.
the transformer used was a 1000VA 2x40VAC backed up with 6x68.000uF cap bank.
The problem i had with resistors in place was welding of the rèley, resistor burning and blowing the main fuse (16A) at allmost every startup. With CL60's they have now been working just fine for 3-4 years.
the transformer used was a 1000VA 2x40VAC backed up with 6x68.000uF cap bank.
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