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50 watt build no sound
Posted: Sun Feb 19, 2017 2:33 pm
by topsportsmanta1
ok u guys who no these things like the back of ur hands
just built a 50 watt i have no sound but when i shut the power switch down i get guitar sound for 3 to 4 sec.
if i keep switching power on and off i get sound
marstran 164 trans
classictone ot
the amp came with the 4 lug carling switches i always use the 2 pole switches does it sound like i have the switches wired wrong?
power on and srandby on i get all accurate voltage readings from v1 too v5
thanks mike
Re: 50 watt build no sound
Posted: Sun Feb 19, 2017 10:15 pm
by axeman
Check you impedance
Re: 50 watt build no sound
Posted: Mon Feb 20, 2017 5:00 pm
by danman
Are all voltage readings normal with the amp out of standby and in normal playing mode? You need to determine if the power supply is wired correctly and you are getitng proper voltages at all points. Be sure to check for proper negative DC bias voltage at pin 5 on both power tube sockets, in standby mode and in playing mode.
Re: 50 watt build no sound
Posted: Mon Feb 20, 2017 7:28 pm
by topsportsmanta1
ok thanks for replying guys
its a marstran jmp 164 trans
brown to power switch
blue to main fuse
all rest tied off
on other side of trans big black n orange to v5
black n brown to ground and f4 can
two reds to rectifier
i have negative 130s on pin 5 on both v4 n v5
like i said if shut the amp down i have guitar sound for 3 to 4 seconds while its powering down all tubes light up
all reading are correct on v1 thru v5 except pin 5 on v4 n v5
these switches i have never used the power switch is a carling with 4 hook ups
standby has 3 hook ups so dont know if i am wiring them wrong i usually use the 2 wire carling switches witch i ordered
please please help
output trans is a classic tone
choke is a classic tone also
Re: 50 watt build no sound
Posted: Mon Feb 20, 2017 7:51 pm
by topsportsmanta1
danman or anybody else i can send photos via text just send me #in a private message would truly appreciate it !!
metro just keeps kicking me out
Re: 50 watt build no sound
Posted: Mon Feb 20, 2017 9:33 pm
by topsportsmanta1
Ok so if i dime the ppmv i get very very little guitar sound almost like a am fm radio wether the standby is on or off !!! Shut power down n its loud as a mofo for 3 to 4 seconds ?
Re: 50 watt build no sound
Posted: Mon Feb 20, 2017 9:40 pm
by axeman
Send me some detailed pics
axeman6@msn.com
Re: 50 watt build no sound
Posted: Mon Feb 20, 2017 10:01 pm
by topsportsmanta1
Sent thanks axe
Re: 50 watt build no sound
Posted: Wed Feb 22, 2017 6:03 pm
by neikeel
Happy to help too, can't you post pics here?
Re: 50 watt build no sound
Posted: Sun Feb 26, 2017 1:26 pm
by topsportsmanta1
I wanna thank all you guys for your help !!!! love all you Marshall maniacs
its working great now
Brian from marstran spent about a total of 6 hrs over the phone diagnosing the problem and got it all figured out his jmp trans is amazing sounding !!!
big thanks to BRIAN !!!! FOR all your help buddy
Re: 50 watt build no sound
Posted: Sun Feb 26, 2017 11:31 pm
by axeman
What was wrong?
Re: 50 watt build no sound
Posted: Mon Feb 27, 2017 4:15 pm
by neikeel
axeman wrote:What was wrong?
+1 please share.
Re: 50 watt build no sound
Posted: Wed Mar 01, 2017 6:10 pm
by topsportsmanta1
i had to go to a 220 bias supply dropping resistor
of all things lol
thanks for all your help guys much appreciated