hi Salas,
How can I add a gain stage to the DCB1 ? Seems like I need more gain in driving the M2.
Thanks
How can I add a gain stage to the DCB1 ? Seems like I need more gain in driving the M2.
Thanks
any recommendation on the circuit that I should try? I like to use 2sk170, still have few around.
Thanks
Thanks
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Use a good op-amp instead because a simple single stage 2SK170 gain preamp will produce much more THD what the DCB1 does before it
I would replace the DCB1 Buffer with a gain stage that accepts your source signals and has sufficient current to drive the cables feeding into your M2.
There are many gain stages described in this forum that are fully capable, without needing a DCB1 in front of them.
Not sure what you mean, the DCB1 has no separate power supply board, and required power input is AC not DC. Does your board have rectifiers and filter caps? Mist of the circuitry on the DCB1 board is the shunt power supply. What exactly do you have?
It looks as if someone has cut off the power supply section assuming off course that it's a store board.
Keeping with the orientation in your photo the rail voltages pins to the right should be connected like in the annotated attachment. Someone obviously hacked off the shunt PSU section either to use it standalone for powering a Soekris etc. or could not fit the full board with sinks in an integrated build and split it or had another supply fitted already or had some other practical reason like that.
Attachments
It can't be a DCB1.
There was the original, then the Hypnotize and Mesmerize followed by the hotrodded.
All had the PSU integrated on the PCB.
The Hyp had one relay,
The Mes had 7 relays. Post5548 shows 7 relays with two left empty.
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It will rather work like this but not sure of quality or hum
Attachments
I have not heard a B1 so can't compare directly.
I am surprised that the B1 is being reported as audibly inferior to the DCB1 since they are essentially the same circuit, a jFET Follower with CCS loading.
Both the DCB1 and the B1 will have a DC blocking capacitor before and after the Buffer stage, unless some considerable "other circuits" are added to minimise the effects of DC getting to the speaker load.
I am surprised that the B1 is being reported as audibly inferior to the DCB1 since they are essentially the same circuit, a jFET Follower with CCS loading.
Both the DCB1 and the B1 will have a DC blocking capacitor before and after the Buffer stage, unless some considerable "other circuits" are added to minimise the effects of DC getting to the speaker load.
none.
But you may find that performance is very slightly changed from the recommended 20k vol pot.
But you may find that performance is very slightly changed from the recommended 20k vol pot.
Thanks, Andrew. I thought I read somewhere in the thread that you need to change a resistor value to accommodate the 50k pot.
I don't think so. It just feeds the Buffer with a slightly higher source impedance and that will affect the accidental RF filter created by the input capacitance of the jFET.
Better to use a lower value vol pot and add proper RF attenuation filtering that does not change with signal voltage.
Better to use a lower value vol pot and add proper RF attenuation filtering that does not change with signal voltage.
We used to put 560k instead of 220k input to ground resistor for 50k pot just to keep the ratios same as with the standard 20K pot but its not really significant. We usually preferred the 20K pot 220k arrangement slightly better subjectively.