[QUESTION] ROCK/PAB/JAZZ 3-way toggle

[Max]

Rock/Jazz (Guitar/Mic) switch of the original ODS amps from 1st to 5th generation:

1st generation ODS amps: 2-position sliding switch without an intentional PAB position but with the possibility to dial in some kind of PAB-tone halfway between Rock and Jazz.

2nd generation ODS amps: 2-position sliding switch without an intentional PAB position but with the possibility to dial in some kind of PAB-tone halfway between Rock and Jazz.

3rd generation ODS amps: 2-position toggle switch without an intentional PAB position but with the possibility to dial in some kind of PAB-tone when (with some fumbling and patience) you convince this toggle switch to stay in the position between Rock and Jazz.

transition generation ODS amps (introduction of the 'classic' tone stack, the trigger pot OD entrance, the ratio control and/or the presence control and built after the 3rd and before the 4th generation): 3-position toggle switch with an intentional PAB position in the middle.

4th generation ODS amps (classic tone stack, deep switch, trigger pot OD-entrance, ratio control, presence control): 3-position toggle switch with an intentional PAB position in the middle.

5th generation ODS amps (skyline tone stack, mid switch, trigger pot OD-entrance, ratio control, presence control) 2-position toggle switch without an intentional PAB position in the middle.

Caveat!: This info is based on my personal experience with only around 20 original ODS amps. And IMO 20 of probably more than 200 existing original ODS amps might be a rather small base for general conclusions, even more so because these amps are custom made.

Cheers,

Max

[Bombacaototal]

Thank you very much everyone who chimed in. It is indeed very helpful!

I have made some amendments to my initial schematic and I think the wiring (based of #124) is correct now on a ON-OFF-ON switch without the relay. Would anyone mind to verify? I am also wondering if the 22M on each side would be needed at all (I would assume not as 3rd and 2nd gen do not have it)?

... and if I understood correct from Talbany (with thanks) the 22M is used to reduce loading on the relay board and hence not needed on a build without relay, correct!?

The only difference then being the lack of 22 or 10M resistors on the relay board in the center off reduces the loading

[EDIT] schematic updated further down

[sluckey]

Those 22M will do nothing. They are wired wrong.

[Bombacaototal]

Those 22M will do nothing. They are wired wrong.

Thanks Sluckey. I guess I just need to remove both 22M and then good to go!?

[sluckey]

Thanks Sluckey. I guess I just need to remove both 22M and then good to go!?

Usually when there are high value resistors on a switch the reason is to prevent a popping sound when the switch is operated. But without seeing the original schematic I can't say if this is the purpose in this case. But in any case, your 22Ms are wired wrong. Take a close look and you will see that each leg of the resistor is connected to the same point. IOW, the resistors are shorted out and therefore do nothing.

[talbany]

Rock/Jazz (Guitar/Mic) switch of the original ODS amps from 1st to 5th generation:

1st generation ODS amps: 2-position sliding switch without an intentional PAB position but with the possibility to dial in some kind of PAB-tone halfway between Rock and Jazz.

2nd generation ODS amps: 2-position sliding switch without an intentional PAB position but with the possibility to dial in some kind of PAB-tone halfway between Rock and Jazz.

3rd generation ODS amps: 2-position toggle switch without an intentional PAB position but with the possibility to dial in some kind of PAB-tone when (with some fumbling and patience) you convince this toggle switch to stay in the position between Rock and Jazz.

transition generation ODS amps (introduction of the 'classic' tone stack, the trigger pot OD entrance, the ratio control and/or the presence control and built after the 3rd and before the 4th generation): 3-position toggle switch with an intentional PAB position in the middle.

4th generation ODS amps (classic tone stack, deep switch, trigger pot OD-entrance, ratio control, presence control): 3-position toggle switch with an intentional PAB position in the middle.

5th generation ODS amps (skyline tone stack, mid switch, trigger pot OD-entrance, ratio control, presence control) 2-position toggle switch without an intentional PAB position in the middle.

Caveat!: This info is based on my personal experience with only around 20 original ODS amps. And IMO 20 of probably more than 200 existing original ODS amps might be a rather small base for general conclusions, even more so because these amps are custom made.

Cheers,

Max

Thanks! (just the Facts) Max

That is correct the 22m resistors are there to reduce any popping when you hit the PAB (Float the bass pot)

Tony

[Bombacaototal]

Many thanks Tony and Sluckey. No need for those 22M without relay then. Updated schematic below for future reference

[pompeiisneaks]

I don't think the meaning they were giving was that only relays cause popping. Any switch of any kind can cause popping. You do not 'need' the 22M resistors for the switch to work, and your version should work as you want, but you may get a popping noise.

This is because as the switch disconnects and reconnects there's a build up of current that needs to go somewhere and sometimes it arc's across the contacts, thus making an audible 'pop' in the signal path. To avoid this a large resistor allows a slow current path somewhere for this until the switch engages on the opposite side and creates a new path for the electrons.

If you look at the original schematic you're pulling this from, they're across a different part of the circuit, they jump between the right side of the switch and some other part of the circuit. I.e. the top connection on the Rock/Jazz switch has a 22M that jumps to the line that connects between the Bass Pot wiper and the bottom connection of the pab relay bottom input. The second 22M resistor jumps between the bottom connection of the Rock/Jazz switch and the top PAB switch input and the treble bottom end of the wiper. Understanding that path will help if you want to restore the 22M resistors. If not, you can just put up with the pop noise.

~Phil

[Bombacaototal]

I don't think the meaning they were giving was that only relays cause popping. Any switch of any kind can cause popping. You do not 'need' the 22M resistors for the switch to work, and your version should work as you want, but you may get a popping noise.

This is because as the switch disconnects and reconnects there's a build up of current that needs to go somewhere and sometimes it arc's across the contacts, thus making an audible 'pop' in the signal path. To avoid this a large resistor allows a slow current path somewhere for this until the switch engages on the opposite side and creates a new path for the electrons.

If you look at the original schematic you're pulling this from, they're across a different part of the circuit, they jump between the right side of the switch and some other part of the circuit. I.e. the top connection on the Rock/Jazz switch has a 22M that jumps to the line that connects between the Bass Pot wiper and the bottom connection of the pab relay bottom input. The second 22M resistor jumps between the bottom connection of the Rock/Jazz switch and the top PAB switch input and the treble bottom end of the wiper. Understanding that path will help if you want to restore the 22M resistors. If not, you can just put up with the pop noise.

~Phil

Hi Phil, thanks for clarifying and for the help as always.

I would like top add the 22M to stop the current build up of current but I am really struggling to find a way to do it without the advent of the PAB relay. Hopefulyl I can leave with the popping

[Bombacaototal]

For future reference I bought this switch for the ROCK/PAB/JAZZ https://modulusamplification.com/Miniat ... 25369.aspx

[Bombacaototal]

Reviewing several ODS layouts and I found curious that HAD usually wired the DEEP control to work with the ROCK setting only. Any reason for that?
Would it make sense to wire the DEEP to the middle of the DPDT ON-OFF-ON and have it working with the JAZZ as well?

[ayan]

I've seen two amps with a 3-way (on-off-on) Jazz/Rock switch, one of them being 124, without which... Anyway, in the other amp, a high plate classic 50 watter from 1982/3, the PAB switch was a sliding type and did not have a ground connection until I added it years ago. The owner would achieve the PAB sound by either using the footswitch, or the center position of the J/R switch. Now, while the sound of the J/R switch and the PAB are the same to most everyone, the circuits are not identical due to the 22 Meg resistors in the PAB. At the time he got them amp, John Goux pointed out to Dumble that the two sounds were not identical, to which Dumble responded "I'm surpirsed you can hear that." End of story.

Gil

Rock/Jazz (Guitar/Mic) switch of the original ODS amps from 1st to 5th generation:

1st generation ODS amps: 2-position sliding switch without an intentional PAB position but with the possibility to dial in some kind of PAB-tone halfway between Rock and Jazz.

2nd generation ODS amps: 2-position sliding switch without an intentional PAB position but with the possibility to dial in some kind of PAB-tone halfway between Rock and Jazz.

3rd generation ODS amps: 2-position toggle switch without an intentional PAB position but with the possibility to dial in some kind of PAB-tone when (with some fumbling and patience) you convince this toggle switch to stay in the position between Rock and Jazz.

transition generation ODS amps (introduction of the 'classic' tone stack, the trigger pot OD entrance, the ratio control and/or the presence control and built after the 3rd and before the 4th generation): 3-position toggle switch with an intentional PAB position in the middle.

4th generation ODS amps (classic tone stack, deep switch, trigger pot OD-entrance, ratio control, presence control): 3-position toggle switch with an intentional PAB position in the middle.

5th generation ODS amps (skyline tone stack, mid switch, trigger pot OD-entrance, ratio control, presence control) 2-position toggle switch without an intentional PAB position in the middle.

Caveat!: This info is based on my personal experience with only around 20 original ODS amps. And IMO 20 of probably more than 200 existing original ODS amps might be a rather small base for general conclusions, even more so because these amps are custom made.

Cheers,

Max

Thanks! (just the Facts) Max

That is correct the 22m resistors are there to reduce any popping when you hit the PAB (Float the bass pot)

Tony

[Bombacaototal]

I am slightly confused with the wiring of the Rock/Jazz. I attach a cut of the layout of #124.

Taking the assumption that the switch is a DPDT ON/OFF/ON, wouldn't the toggle UP on the schematic be equivalent to Jazz? On the layout (in my opinion) it looks like the wiring is updside down, or am I missing something?

[martin manning]

In these and most toggle switches, the internal connections are on the side opposite the bat position.

[Bombacaototal]

In these and most toggle switches, the internal connections are on the side opposite the bat position.

Ah, that makes sense now. I think I wired all my toggles upside down