Cadorman
Ambassador of the Catocaster
Looks like you spilled a little bong water there.
Guess what?
- Thread starter mcblink
- Start date
OP
mcblink
Ambassador of Riffs & Spliffs
Great news man keep it up
Amp Mad Scientist
Ambassador of Heresy
OK
I don't have the board in front of me so I can't tell a lot..
but there's something about this I don't get at the moment.
Go ahead and
Set the meter for DC volts.
Connect black probe to the chassis.
Connect red probe to pin 5 of the output socket.
You can do this from the top of the socket, you don't need to do this inside the amp.
2. Turn the power on, but leave the standby set to "warm-up."
Do not turn the standby to "operate."
3. You should read -42 volts DC on pin 5 of each socket. Leave the probe stuck into pin 5 from the top of the socket.
4. Now turn the standby to "operate" for about 10 seconds.
How much did the -42 volts DC pin 5 change when you switched the standby to "operate ?"
5. Test all 4 sockets pin 5.
Write down how much the -42 volts changes, when you turn the standby to operate.
6. Now report how much the voltage changed on each socket.
Standby "warm up" = what voltage on pin 5?
Standby "operate," what voltage on pin 5?
Report the DC readings for all the output sockets pin 5..difference between warm-up and operate?
OP
mcblink
Ambassador of Riffs & Spliffs
Will report back shortly
OP
mcblink
Ambassador of Riffs & Spliffs
Each socket reads about -41.5 vdc
OP
mcblink
Ambassador of Riffs & Spliffs
All were about -42 before standby in warm up, then were about-41.5 after standby switch to operate
I’ll shut up now.....
Amp Mad Scientist
Ambassador of Heresy
OK
Now turn the standby to operate.
What DC voltage is on pin 3?
What DC voltage is on pin 4?
Check all 4 output sockets and report the DC voltage pins 3 and 4.
Amp Mad Scientist
Ambassador of Heresy
OK turn standby to warm-up. Do not turn standby to operate.
Turn power on.
Set meter to AC volts.
Connect black probe to chassis.
Connect red probe to pin 2, what is the AC voltage on pin 2 of the output socket?
Connect red probe to pin 7, what is the AC voltage on pin 7?
Test all 4 output sockets.
Report the AC volt readings for pin 2 and pin 7 of each output socket.
OP
mcblink
Ambassador of Riffs & Spliffs
3.7 AC across all sockets pin 2
3.7 AC across all sockets pin 7
Amp Mad Scientist
Ambassador of Heresy
OK now plug a speaker cable into your speaker cabinet.
This must be a real speaker cable, not a guitar cable.
Measure the free end of the speaker cable with the ohm meter.
What is the ohm reading?
Amp Mad Scientist
Ambassador of Heresy
OK so the speaker must be connected to the 16 ohm out of the amp.
Now, do you know how to set the bias on a TSL?
couldn’t resist....
Amp Mad Scientist
Ambassador of Heresy
Pizza pick up, the pizza is across the street.
Be right back.
But in the meantime, I would like you to set the bias to 85 ma per side.
Normally this is 90 ma, but we are setting it a bit cooler than normal.
Do you know how?
Be right back.
But in the meantime, I would like you to set the bias to 85 ma per side.
Normally this is 90 ma, but we are setting it a bit cooler than normal.
Do you know how?
OP
mcblink
Ambassador of Riffs & Spliffs
Yes, I've set bias with this amp many times but what do you mean MUST connect to the 16 ohm jack? This is what I normally do, but is this related to the jack grounding issue I've heard tell about? I have only 1 1960A that I've ever used at @ 16ohms
Spliff....
