Type: Posts; User: vintagekiki; Keyword(s):
Resolution is not a problem, accuracy is a problem.
Adjusting to point where idle current just begins to rise, measured with 200mV DVM and read on penultimate digit, is only possible with helipot...
In order not to make a breakdown without need, between power supply and PCB pwr, in series with power supply voltage +40V and -40V set current limiter in form of resistors 100 Ohm / 50W.
I think that Marshall series MG100... in output uses IC TDA7293.
Maybe can help schematis for Marshall MG100HDFX
I'm very curious how to measure 10mA at 0.33 Ω.
Ohm's law says it is 3.3 mV. With analog Vmeter can hard to measure, but DVM has walking on display +/- 1 digit.
Autotransformer enables that...
When you plug guitar into Return jack, do you get clean or distorted sound?
Bias current is measured by connecting DC mA meter (range 200 mA) in series with emitter resisistor 0.33.
Partridge HI100-O OUTPUT TRANSFORMER
Blue wire is probably 100V line & NFB
Fixed bias is fixed bias. Hybrid bias with cathode resistor hm hm. Bias is not very stable, knows depends from tube to tube.
Perhaps the winning combination is reduce voltage g2 to value between 1/2...
You're right. Now I find that voltage doubler is powered by 15VAC transformer.
Definitely no escape from horrors. The voltage doubler should be converted to a voltage tripler, and with the choice of...
The idle current value depends from tube to tube. The guaranteed value of idle current is only when using original factory tubes (Part no ... ...)
To reduce idle current, a negative bias for the...
Alamo Capri Model 2560
Input 110 acv connects to main (power) transformer T1
Output transformer test with ohmmeter
Input = primary = high resistance
Output = secondary = low resistance
Input is connected to the anode tube
Output is connected to the speaker
- Have you tried replacing tube with a new one (not like new). Best try Boogie low noise tube SPAX7-A
- When connects to gnd microphone...
Are electrodes (g1 / k / a) of half unused tube connected to gnd ?
Look angelfire link.
Something from Akai Reel Tape Decks
Try to follow Troubleshooting page 26
No need to spam thread with same request.