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I am working with a Peavey Classic Series VT amp. I am trying to understand what output options the “Selector” and "Combiner” buttons provide when plugged into the Automix jack. I’d like to set out my understanding with the hope that someone can confirm that I’ve got it right, or let me know where I’ve gone wrong.
As I understand it. . . . When plugged into the Bright channel the signal goes to U1A, then to U4 then to U5A and through the rest of the amp. The signal also goes to U2. If there is no plug in the Automix jack, however, Q1 turns U2 off so the signal does not reach U1B. Thus, what one hears at the speakers is the Bright channel signal only.
When plugged into the Normal channel, the signal goes to U1B, then to U3, then to U5A and on through the rest of the amp. Thus, what one hears at the speakers is the Normal channel signal only.
When plugged into the Automix jack the “Combiner” and “Selector” buttons on the footswitch become active. The Combiner button toggles between activating and deactivating the Selector button. When active, the Selector button toggles between turning off U3 or U4. Plugging into the Automix jack also causes Q1 to turn on U2 so the Bright channel signal can reach U1B.
With respect to the signal, when plugged into the Automix jack, the signal goes from the tip of that jack to U1A, then to U2, then to U1B. The signal that emerges from U1B is a combination of the Bright and Normal channels. That combined signal then goes to U3, then on to U5A and through the rest of the amp. The Bright channel signal also seems to take a “parallel” path through U1A, on to U4, then on to U5A and the rest of the amp.
If the Combiner switch is open, then the Selector switch is inactive, U1A and U1B are both turned on, and the combined Bright channel/Normal channel signal goes through U1B and reaches U5A. The parallel Bright channel signal goes through U1A and also reaches U5A. Thus, the combined Bright/Normal channel signal along with the parallel Bright channel signal is what one hears at the speakers.
If the Combiner switch is closed, then the Selector switch is active to turn off either U1A via U4, or U1B via U3.
If U1B is turned off via U3, then the cross-fed signal from the combined Bright channel/Normal channel signal does not reach U5A. The parallel Bright channel signal, however, does reach U5A through U4. Thus what one hears at the speakers is the Bright channel only.
If U1A is turned off via U4, then the combined Bright/Normal channel signal reaches U5A and goes on through the rest of the amp. The parallel Bright channel signal does not make it to U5A. Thus, what one hears at the speakers is the combined Bright/Normal channel signal only.
I've attached a schematic of the Classic VT Series preamp with my markups, which may help show what I'm talking about.
The upshot of all this, as I understand it is . . . . The output options through the Automix jack and footswitch are: 1) combined Bright/Normal/Parallel Bright; 2) Bright only; and 3) combined Bright/Normal only. Further, the Automix jack/footswitch does not provide a Normal channel only option. Have I got this right?
Thanks
John
As I understand it. . . . When plugged into the Bright channel the signal goes to U1A, then to U4 then to U5A and through the rest of the amp. The signal also goes to U2. If there is no plug in the Automix jack, however, Q1 turns U2 off so the signal does not reach U1B. Thus, what one hears at the speakers is the Bright channel signal only.
When plugged into the Normal channel, the signal goes to U1B, then to U3, then to U5A and on through the rest of the amp. Thus, what one hears at the speakers is the Normal channel signal only.
When plugged into the Automix jack the “Combiner” and “Selector” buttons on the footswitch become active. The Combiner button toggles between activating and deactivating the Selector button. When active, the Selector button toggles between turning off U3 or U4. Plugging into the Automix jack also causes Q1 to turn on U2 so the Bright channel signal can reach U1B.
With respect to the signal, when plugged into the Automix jack, the signal goes from the tip of that jack to U1A, then to U2, then to U1B. The signal that emerges from U1B is a combination of the Bright and Normal channels. That combined signal then goes to U3, then on to U5A and through the rest of the amp. The Bright channel signal also seems to take a “parallel” path through U1A, on to U4, then on to U5A and the rest of the amp.
If the Combiner switch is open, then the Selector switch is inactive, U1A and U1B are both turned on, and the combined Bright channel/Normal channel signal goes through U1B and reaches U5A. The parallel Bright channel signal goes through U1A and also reaches U5A. Thus, the combined Bright/Normal channel signal along with the parallel Bright channel signal is what one hears at the speakers.
If the Combiner switch is closed, then the Selector switch is active to turn off either U1A via U4, or U1B via U3.
If U1B is turned off via U3, then the cross-fed signal from the combined Bright channel/Normal channel signal does not reach U5A. The parallel Bright channel signal, however, does reach U5A through U4. Thus what one hears at the speakers is the Bright channel only.
If U1A is turned off via U4, then the combined Bright/Normal channel signal reaches U5A and goes on through the rest of the amp. The parallel Bright channel signal does not make it to U5A. Thus, what one hears at the speakers is the combined Bright/Normal channel signal only.
I've attached a schematic of the Classic VT Series preamp with my markups, which may help show what I'm talking about.
The upshot of all this, as I understand it is . . . . The output options through the Automix jack and footswitch are: 1) combined Bright/Normal/Parallel Bright; 2) Bright only; and 3) combined Bright/Normal only. Further, the Automix jack/footswitch does not provide a Normal channel only option. Have I got this right?
Thanks
John
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