Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ginger on October 17, 2018, 04:58:40 pm
-
Any thoughts on how to increase the intensity on this one ?
-
I'd consider reducing the value of R54, or increasing the value of the pot R55. But the former is easier. You could parallel R54 with a pot or fixed resistors to find a combined lesser value you like.
-
Ok.. thanks , I'll change the resistor vaue
-
changing R54 might work but only if the NE-2H Neon, as designed in the circuit, doesn't light to its full illuminosity (spell check is saying that isn't a word, but I think it is...). a NE-2H has a breakdown voltage of about 90v, but the maintaining voltage is higher, so if Danelectro didn't design this neon to get as bright as possible at maximum setting, then yes.. changing R54 might help.
you also might have a weak NE-2H. So you can replace that too.
also, R54/R55 can only deal with what the oscillator gives it. You might try swapping in a new 12AX7 as a test.
if the oscillator is full tilt max performance and the NE-2H is shining as bright as possible, you can look at the signal side of the tremolo device: the 220K R9 is the top half of a voltage divider and the bottom half is the [ impedance of R13+R14+R15 (1.168M) + the value of the LDR ] . When the LDR is dark, it is probably very high, 5M or 20M.,you can measure that with the amp turned off. so when "dark", the LDR has little influence on the voltage divider. When the NE-2H fires, the 'light' resistance of the LDR kicks in... (harder to measure that resistance in the circuit, you might with an analog ohmmeter....)
All that is to say, you can try to change the LDR value too.. the LDR might have a light value of 100K or 5K. the lower that value the more it'll turn down the volume at the tremolo rate.
if you have a fender trem roach on hand, try to swap it for the neon and LDR and see what happens.