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Title: finished...are these voltages ok? Post by: RiffRaff on November 10, 2009, 06:11:22 AM Finished building my OTS
started it up with a current limiter and it looked good so I fired it up no sound ...so I'm hoping some of you fine gents can help me out V1 pin1=193 pin3=1.8 pin6=202 pin8.001 V2 pin1=200 pin3=1.9 pin6=207 pin8=.001 V3 pin1=301 pin3=59 pin6=301 pin8=.001 V4 pin3=463 pin4=461 pin5=54 pin6=463 pin8=.039 V5 pin3=463 pin4=462 pin5=54.5 pin6=463 pin8=.027 The bias on v5 is 27 and v4 is 39 Is this normal to be that far apart? I'm guessing the low numbers on pin8 of v1,2 and 3 is the reason for no sound I'm still learning the ropes so please take it easy on me Thanks for any help Tim Title: Re: finished...are these voltages ok? Post by: bluesfendermanblues on November 10, 2009, 07:14:48 AM Finished building my OTS started it up with a current limiter and it looked good so I fired it up no sound ...so I'm hoping some of you fine gents can help me out V1 pin1=193 pin3=1.8 pin6=202 pin8.001 V2 pin1=200 pin3=1.9 pin6=207 pin8=.001 V3 pin1=301 pin3=59 pin6=301 pin8=.001 V4 pin3=463 pin4=461 pin5=54 pin6=463 pin8=.039 V5 pin3=463 pin4=462 pin5=54.5 pin6=463 pin8=.027 The bias on v5 is 27 and v4 is 39 Is this normal to be that far apart? I'm guessing the low numbers on pin8 of v1,2 and 3 is the reason for no sound I'm still learning the ropes so please take it easy on me Thanks for any help Tim Anode voltages are fine: Those are the voltages measured on pin 1 and 6 on the tues V1,V2 and V3 hereto pin 3 and 4 on tubes V4 and V5. Your cathode voltages are falulty Those voltages on pin 8 on V1,V2 and V3 looks like your haven't connected these at all - Check again. Do the preamp tubes glow? do they have proper heating voltage between pi 4/5 and 9?? Bias Is very far apart - maybe your V4 and V5 tubes are not properly matched, but if they don't hum or otherwise sound funny, you can keep using untill you get around to buying new ones. Title: Re: finished...are these voltages ok? Post by: RiffRaff on November 10, 2009, 07:52:02 AM Thanks I'll check again in the morning
The preamp tubes were glowing when I took the measurements a 12ax7 is ok for the pi tube or is it a different tube that I need? Title: Re: finished...are these voltages ok? Post by: bluesfendermanblues on November 10, 2009, 08:38:45 AM Thanks I'll check again in the morning The preamp tubes were glowing when I took the measurements a 12ax7 is ok for the pi tube or is it a different tube that I need? 12ax7 is correct Title: Re: finished...are these voltages ok? Post by: RiffRaff on November 11, 2009, 02:59:48 AM opps I was measuring pin 9 instead of 8 on v1 v2 v3
v1 and v2 are 1.7 and v3 is 60 what is the next step to in find out why there is no sound? I plugged a cable in the power amp and it works thanks for helping me out Tim Title: Re: finished...are these voltages ok? Post by: mcinku on November 11, 2009, 07:20:33 AM Did you try to change V1,V2,V3 tubes with something you know it works?
If you crank the Volume knob, ... is the noise level the same or it changes with more volume? When you measured the plate voltages, did you hear any click sound coming out your speaker?... Especially when measuring the V3 tube. Title: Re: finished...are these voltages ok? Post by: RiffRaff on November 11, 2009, 07:37:34 AM Did you try to change V1,V2,V3 tubes with something you know it works? If you crank the Volume knob, ... is the noise level the same or it changes with more volume? When you measured the plate voltages, did you hear any click sound coming out your speaker?... Especially when measuring the V3 tube. I've tried 6 different tubes (all new) there is no noise at all... dead quite yes I heard noise when taking voltages I've checked and double checked input wiring and it seems to be ok I don't know what to do next Thanks for helping Tim Title: Re: finished...are these voltages ok? Post by: bluesfendermanblues on November 11, 2009, 07:42:57 AM Did you try to change V1,V2,V3 tubes with something you know it works? If you crank the Volume knob, ... is the noise level the same or it changes with more volume? When you measured the plate voltages, did you hear any click sound coming out your speaker?... Especially when measuring the V3 tube. I've tried 6 different tubes (all new) there is no noise at all... dead quite yes I heard noise when taking voltages I've checked and double checked input wiring and it seems to be ok I don't know what to do next Thanks for helping Tim Maybee you have colder joints?? Search for the error in this area Title: Re: finished...are these voltages ok? Post by: mcinku on November 11, 2009, 09:13:52 AM I've tried 6 different tubes (all new) there is no noise at all... dead quite yes I heard noise when taking voltages I've checked and double checked input wiring and it seems to be ok I don't know what to do next Thanks for helping Tim What about if you engage the OD and crank those pots, any noise? If you would detect some noise, at least you would know something is wrong with V1 and this will narrow down your search. My guess would be that V1 has some issues. ??? Title: Re: finished...are these voltages ok? Post by: RiffRaff on November 11, 2009, 03:52:29 PM I've tried 6 different tubes (all new) there is no noise at all... dead quite yes I heard noise when taking voltages I've checked and double checked input wiring and it seems to be ok I don't know what to do next Thanks for helping Tim What about if you engage the OD and crank those pots, any noise? If you would detect some noise, at least you would know something is wrong with V1 and this will narrow down your search. My guess would be that V1 has some issues. ??? reflowed all the pins on v1 and nothing Title: Re: finished...are these voltages ok? Post by: bluesfendermanblues on November 11, 2009, 04:02:48 PM Check the wiring to pin 8 and V1, V2, and V3
Are the 5uF + 2,2k properly grounded?? Check with you ohm meter from " - " on the 5uF cap to ground Title: Re: finished...are these voltages ok? Post by: RiffRaff on November 11, 2009, 08:36:44 PM Not sure what side is negative as there are no + or - signs on it
maybe I have it in backwards? here is the best pic I could get with my camera I'll try to get a better pic |