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Rixsta 19th May 2004 11:28 AM

zen v4 0.66v lol no way
i have a problem where across r0 and r1 theres 1.6V
iv'e checked for inverted connections on q3 and checked my wireing.
if i leave the amp on too long the risistor will go up in smoke..
so it's hard to get a good reading on any of the other voltages

Rixsta 19th May 2004 02:01 PM

i desperetly need help here
it's my day off work and i wont be able to continue with building my amp for another 4 days unless someone helps..

maybee the power going into or going out of Q3 is the problem.

well any help would be greatly apriciated..


till 19th May 2004 02:17 PM

_ Does it oscillate, is the 1,6V plain DC or not?

- take away C6 or R16 and leave that connection open, report what happens now, voltage acrosse R0 ?

- Test if Q3 is damaged or soldered in reverse..

- nothing to lol about

- there is way, i know it.

Rixsta 19th May 2004 02:32 PM

by oscillate you mean weird sounds
no it dosent

plain dc theres about .40v or so of ac between r0

you are right there is nothing to lol about my amps nearly compleate apppart from this small problem
the other channel of the amp works fine and is running at about 1.5 amp which keeps those mosfets not so hot...

i disconected r16 voltage across r0 is now 3.20v dc more or less

i will post pictures very soon then youll have something to lol about

by the way nothing can be wrong blown i mean because the amp sounds fine it plays music ok without any strange sounds
just r0 has too many volts and will burn in flames if i leave it on for more than 10 seconds:hot: thats all

till 19th May 2004 02:59 PM


by oscillate you mean weird sounds
no i mean if the bias is stable plain DC or is there an higher frequency AC component. You will not hear but you should measure.

If you a) connected thinks right what you have to check as we canīt
b) Q3 is ok
c) there is no oscillations

ther should be about 0,7V between is base and emitter what is same as across R0.

Rixsta 19th May 2004 03:15 PM

there is 3V between is base and emitter of q3 with r16 disconnected

& the same when when r16 is connected

it seams to be plain dc apart from the .40v or so of ac between r0
i mentioned

i have no osciliscope to mesure oscilations
i will replace q3 now


till 19th May 2004 03:41 PM

you will have to replace it, and check if you made a mistake around it. And make sure to use it not reversed. There is the chance to see oscillation also with a) a DMM with frequency counter b) measuring at a place were you expect pure DC in AC mode of the DMM if it is RMS voltmeter and takes higher frequency also and not only 50Hz or so.

Rixsta 19th May 2004 04:53 PM

i replace q3 and i now have 0.7v across r0 it's a 0.5 ohm resistor which i think makes about 1.4 amp's

now i have another problem i dont think it's so bad

when i turn of the power the music stays on for 20 odd seconds (im only using 5000uf capacitors on the power supply)
q1 and q2 seem to be getting warm like they should q5 isnt but it would probably take a while for q5..

as well when i put my multimetre on where it says 42V in the schematic at the source of q5 the voltage takes 5 minuites to drain after iv'e turned the amp off.

or is this normal ?

eLarson 19th May 2004 04:58 PM

How big are the resevoir capacitors in the power supply? And is there a path for them to discharge?

I've not built a Zen, but I do have a BoSoZ which continues to play music, gradually fading way after the mains are disconnected. I'd say it lasts a good 10 seconds.


Rixsta 19th May 2004 05:02 PM

im only using 5000uf capacitors on the power supply

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