Altec 436c

hi, i'm trying to build a copy of altec 436c with some mods i found on the web, i have a question about the meter: is it a milliammeter or a vu meter? i guess the second but i'm not sure..
thank you all
paolo

pretty sure its not a vu...

dave

It`s a millameter

thank you guys..
so i have other questions: is the milliameter a 100 ma?
here some mods i found:
1) "connect a 1n5400 diode in series with the wire to 6AL5 pin 4 and solder a 4700 uF 16v cap across pins 4 and 5 of the tube."

since this mod is for dc to filamet, i put the cap across 6AL5 pin 3 and 4 that are the pins to filamet in this tube; there must be an error in the text.
doing this mod i found 8.4v dc.. is that correct for tube filament?

2) "put a 100k 2w linear pot with legs 1 and 3 to caps C2 and C3, and jump the wiper of the pot to the center connection of plate resistors."

this is for plate balance; it realizes a variabile resistor parallel to R3 and R4, so the resistance at the plates is now half and the voltage at the plates double ( 142v instead of 65v).. is that ok?

3) all the dc voltages are about 20v more than the schematic because of silicon rectifier.. should i change resistors in order to have the voltages as in the schem?

thank you

paolo

i just began to test the unit and i have a big problem: it over compresses. when the signal goes above the threshold the signal disappear just to come back after a second, but sometimes this start repeating like a loop until i rotate the release pot.. obviously something's wrong, but what? i hope you can help me
paolo

sorry for bother, but i really have no clue how to fix the problem.. so i hope someone here can help me.
thank you
paolo

That sounds like a mismatch between the two halves of your amplifier. Everything must be balanced properly. If it is not, as soon as the compressor starts to work, it makes a 'thump' which then drives the compressor to basically cut off the sound until the release starts again. Again, balance - check for matched resistors, capacitors, tubes, wiring. Try new tubes if everything else looks ok.

thank you dale116dot7, i'll try that.. i just want to add the factthat measuring the current exiting from 6al5 i found 10 ma when compression is not happening, then with compression the current diminishes to 2-3 ma but the output signal, as i said before, disappear..
paolo