I've made a start :) 50w #102

[norburybrook]

Ok voltages;

V1:

pin 1: 201 VDC
2: 0
3: 1.8 VDC
4 and 5 heaters 3.2 V AC
6: 195 VDC
7 : 0
8: 1.9
9: 3.2 Ac

V 2:

1: 207 VDC
2: 0
3: 1.8 VDC
4/5 heaters
6: 203 VDC
7: 0
8 1.9 v DC
9: heater


V 3:

1: 286 vDC
2: 398v DC
3: 61.5 vDC
4/5 heaters
6: 288vDC
7: 38vDC
8: 61.5 vDc
9; heater



shall I do V 4 and 5?


or does this give any hint?

marcus

[lovetone]

with regards to the relay switching you should see 12V on the bar end of the diodes?

[norburybrook]

I've got 5v relays and I'm seeing 4.9 v on both of them, and also at the footswitch 5 pin din.




Marcus

[martin manning]

Yes measure the power tube voltages. Those above look pretty good, excepting V3 pin 2 must be a typo.

[lovetone]

ok so when the relay is off you will get 5 volts on the none bar end of the diode which is what you see at the din socket. when you switch the relay the volts will read ov on the none bar end. If you see 5v then theres a problem with the earth that comes from the switch.

[norburybrook]

ok so when the relay is off you will get 5 volts on the none bar end of the diode which is what you see at the din socket. when you switch the relay the volts will read ov on the none bar end. If you see 5v then theres a problem with the earth that comes from the switch.

Thanks, just talking the dog for a walk and I'm going to check all this out.

Just found this post from a while ago:

PostPosted: Thu Oct 11, 2012 1:43 pm Post subject: Reply with quote


I like and have used the Omron relays in builds.
You need to watch which ones that you use though.
I have had to reverse the polarity on the diode for them to work on
the last build. Must be a different designation on the part numbers.
Got that one at Rat Shack.

Nice work on the boards Doug.
_________________
Mike




Might be worth me checking this out, I'll have a look at the tech paper on the mouser site for the relays I have and see if it sheds any light.


Marcus

[lovetone]

None of that makes any difference the coil has no polarity, provided the positive supply is to the bar end of the diode they should work.

More than likely the reason for no output is that the contacts are wired wrong, this is an easy mistake.

you can by pass the contacts

Simple, attache a wire from the 0.047uf on the output of V1b and wire it to the 0.022uf on the input of the phase inverter, turn the volume down as the master is by passed you should now have the clean channel working. If not then you have other problems.

Hope that helps

Geoff

[norburybrook]

thanks Geoff,

I have 5 v when off and 0v when on as you say.

I cannot hear any actual mechanical switching noise though and I'm in my studio which has a very quiet noise floor.

should I hear the switching?

Marcus

[norburybrook]

Ok Martin you were right the V3 pin 2 was a typo missing decimal point 38.8 vDC this morning


V4:

pin 3; 462 VDC
pin 4; 453
pin 5; -48
pin 6; 452



V5:


pin 3; 452
pin 4; 451
pin 5; -47.8
pin 6; 450





back to these relays!!


marcus

[norburybrook]

None of that makes any difference the coil has no polarity, provided the positive supply is to the bar end of the diode they should work.

More than likely the reason for no output is that the contacts are wired wrong, this is an easy mistake.

you can by pass the contacts

Simple, attache a wire from the 0.047uf on the output of V1b and wire it to the 0.022uf on the input of the phase inverter, turn the volume down as the master is by passed you should now have the clean channel working. If not then you have other problems.

Hope that helps

Geoff

can I attach the other end from the V1b to the 3 pin of the master volume instead?

Marcus

[martin manning]

can I attach the other end from the V1b [coupling cap] to the 3 pin of the master volume instead?

Yes, you could do that, but the master and loop jacks are sill in the signal path. If you get no sound, try connecting to the PI input cap as well to rule out a problem in the loop jacks.

The mechanical switching noise of the relays is pretty low. Use your meter to check resistance across the NO and NC contacts. NC's should be zero ohms when the relay is not energized, and NO's something greater or infinite. This should reverse when the relay is switched on, NO's go to zero and NC's larger.

[norburybrook]

Ok wiring up from the .047 to the master volume and I get sound, the tone controls work but it's very very quiet , with the master at 12 and the volume at 12 its quieter than my 5w Se amp.

Also when I switch the impedance selector from the 16 to 8 and then 4 I get a high pitch squeal increasing in level as I hit the 4.


So first things first, I should get this sorted before I tackle the switches I think.

is it the output primaries?


edit I'm going to try going straight to the PI as suggested first.


Ah.......... the blast of reversed output primaries...........always gets me.....


one day i'll get it right, I've been 100% wrong so far.

anyway, V1b straight to PI and I have a wonderful ,full clean guitar sound


Marcus



marcus

[martin manning]

Woo-Hoo! Put a patch cord across the loop jacks and try jumping to the top of the MV again.

[norburybrook]

jumpered to master and all works fine, including a patch across the loop.



All tone controls work great, however the mid switch isn't working?

(edit; found the mistake with the switch.)


So I have a good working clean channel



so back to these bloody switches, what next?



Marcus

[martin manning]

Does the PAB switch/relay work now? Maybe sort that out first since it is in the clean section and a bit simpler than the OD switching.