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★★ Free PCB for JLH 2005 Class-A Amplifier

Hi,
so I just ended soldering the JLH boards, wired everything, plugged it in, and.. the fuses burned out..
my configuration:
toroidal transformer with dual 18.6V
the power supply that is suggested on the site, it's output is -25 0 +25
the speakers are 4Ohm (as measured with my multimeter)
the preamp is a tube one, checked with my headphones before so it should be working ok.

the fuses on the power supply, and on one of the JLH boards burned out. I think the front audio panel on my computer burned as well..
i changed the fuses on the power supply and connected the JLH board with intact fuse, and.. the C1 capacitor went smokin'..

any ideas how to debug where the problem might be? one board at a time..
or should i give up DIY and buy a yamaha amp?
 
I'm running fast out of components..

I've resoldered the board. removed C3 and shorted it as in some previous post. without connecting it to the speakers the output voltage is 25V. tried to play with VR1, VR2, VR3, the output voltage did not change.
any ideas?
 

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I have 4 big toroid transformer which were disassemblyed fron an US made auido equipment, like new. They are 110V and usless for me. I would like to send it to those who want to buy JLH amplifier full kit + Power supply for free

This transformer is ideeeeeeal for Stereo JLH power amplifier (for US and canada DIYers). Spec:

Power: >150W
output1: 24-17-0-17-24
output2: 8V
weight: 2kg

Only 4 available, only one for one person.
Plus $25 for air shipping. PM me if you have interest.

Ray,
You,ve got PM
-Chas
 
I'm running fast out of components..

I've resoldered the board. removed C3 and shorted it as in some previous post. without connecting it to the speakers the output voltage is 25V. tried to play with VR1, VR2, VR3, the output voltage did not change.
any ideas?

on the first pic, you sure have a blown transistor. and the cables to the output transistor have been very hot.
do you massure 25V on speaker output?
 
Salas, sorry, thought they would be scaled correctly.

AudioSan, yes, the output is 25V. the wires were not hot, it's the smoke from the blown transistor, too bad I didn't record it, it was pretty awesome..

while testing, the input should or should not be connected?

it's my first audio DIY project and I am still struggling to understand how things work.. I'm waiting to get some free time to start debugging it, checking voltages along the way, may be verify the transistor states...
 
AudioSan, it blew up after I messed arround with VR1. Unfortunately yesterday i shorted the Q3 again (always use goggles) with the test probe, while measuring the voltages , so now I'm out of components for further testing.. but the preliminary tests showed that the voltages for tr1 - tr4 do not have the values (I mean translated to 25V rail) they should be according to the JLH test table. it's on hold till I get the spare components to blow up.. er.. fix it.
but thnx for trying to help, may be I get it right in a year or so.. :)