the Poor Man 660 support thread

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Hey , can anyone help me with this heater resistor  thingy , ok know matter what resistor i connect to r15 i do not seem to get a voltage drop for the heater supply , what  am i doing wrong ?

regards


skal1
 
skal1 said:
Hey , can anyone help me with this heater resistor  thingy , ok know matter what resistor i connect to r15 i do not seem to get a voltage drop for the heater supply , what  am i doing wrong ?
measuring without tubes in ?
 
That what i thought , so no load means no voltage drop .If i connected two 8v 2.5A bulbs in parallel to the heater out put  would this simulate the two signal pcbs?

@lolom


regards

skal1
 
Yes it will simulate it, but with an error... I don't think they will take 2,5A if the voltage drop thru R15 tends to give you 6.3V... You can measure the current anyway thru R15 with the ohm law I=U/R15 to know if you're close to the ideal value for R15 or not...
 
Maybe for the next batch of pm660 pc boards you can put a little more room for transisor sockets for q1 q2 and q3.  Many thanks
 
ok just hooked up 1 chan of the poor man but it does not sound right , i have checked the supply to the board with out tubes in and that is ok .


245=250

137=139

the 17v rails are ok too the heater voltage is 6.4

With tubes in i am getting really low voltage on the 245v and 137v  so 245v equals 40v and 137=20v every other voltage is ok , bacisally under load strange things are happen  any clues.javascript:void(0);

regards

skal1



 
Hey veermaster that post has no conclusion to their  problem  :mad: it seems funny that the psu is ok  without the signal board connect and ok with signal board connected without tubes in ,this makes think that irf840/820 can not handle the load of the 4  tubes properly , so tomorrow i will try subing the 820 for the 840 and see what happens then.

regards


skal1
 
ok this might be a silly ? , i have injected a 0.776v sine wave in to the poor man ,which i have read is  0db so why is it that the poor man is clipping on my master meter on my o1v , i can hear the compression but with the led meter sticking at clip i can not see what happen , do i need some sort of volume control on the output or am i missing some thing.  ???


regards

skal1


 
skal1 said:
ok this might be a silly ? , i have injected a 0.776v sine wave in to the poor man ,which i have read is  0db so why is it that the poor man is clipping on my master meter on my o1v , i can hear the compression but with the led meter sticking at clip i can not see what happen , do i need some sort of volume control on the output or am i missing some thing.  ???


regards

skal1
You have two controls. Input and threshold. Turn the threshold at min to achieve no compression and tune the input to have 0 db. Then you are at unity gain . Than if you turn threshold you will notice some compression at some point
 

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