Could I get some eyes on this schematic please?

[drew.spriggs]

Top - Sziklai RM-thing.
Bottom - CMOS Muff.

Built, zero sound from the top side and super quiet, very trebly output from the bottom side. Only have done a quick poke at voltages and everything looks fine - I've got supply, vref and about 7v going to the 4007.

Thanks!

 

[Feral Feline]

Pics of the build are needed.

If the schematic is correct, that doesn't mean the build is to spec.

Can't see a cold solder-joint on the schematic...


Speaking of the schematic... I've never seen a "Sziklai" Ring Modulator before, but nonetheless I don't see how that can Ring when there's no carrier-signal to Modulate.

 

[drew.spriggs]

Pics of the build are needed.

If the schematic is correct, that doesn't mean the build is to spec.

Can't see a cold solder-joint on the schematic...


Speaking of the schematic... I've never seen a "Sziklai" Ring Modulator before, but nonetheless I don't see how that can Ring when there's no carrier-signal to Modulate.

Rangemaster, not ring modulator.

More just seeing if I missed something super obvious on the schematic upfront at this stage - I have a scope/etc but thought I'd start at the beginning to see if it was ever going to work on the first place

 

[lowpitch]

The Rangemaster circuit looks sound. VOL1 is kind of superfluous because GAIN1 does pretty much the same thing, but other than that it should work. Maybe a mixup with transistor pinouts?

 

[Feral Feline]

RM ≠ Ring Modulator...? Oh... well, that changes everything.

I'd put a minimum resistor in series with your BIAS pot, that way it can't go all the way down to zero. I don't know what the split should be, but I'd start with a 50k resistor and B50k pot, or maybe a 20k resistor and B50k or B100k pot?


Here's Steve "SmallBear" Daniels' sziklai RangeMod...master, in case you've not seen it...

OhMySziklaiRM NPN by Small Bear

Note the PDR 1M on the output.
Don't know if any of this is of use to you, but thar it be.

 

[drew.spriggs]

The Rangemaster circuit looks sound. VOL1 is kind of superfluous because GAIN1 does pretty much the same thing, but other than that it should work. Maybe a mixup with transistor pinouts?

Yeah I figured that would be the case, but being able to keep high drive and low signal might be useful for driving the Muff thing after.

You might be right with the pin out - I've just found a few with conflicting info, so might just test them to check I haven't done anything stupid