Charge pumped rangemaster?

[JakeFuzz]

Trying to build up a charge pumped rangemaster with an OC44 in a 1590A. Made both a vero layout and put it on breadboard. I am getting extremely odd behavior when the circuit is run in charge pump generated -9 volt mode with the reference to normal ground. The circuit is distorting much more than any other RM i've heard and has a strange fizzle when pushing a driven amp. The distortion is very nice actually but the fizzle is obnoxious.

I have done the usual tests like swapping the transistor for low leakage devices. Swapped the charge pump. Tried it on breadboard to isolate the grounds and move the power section a little further away from the audio. The voltages read identically when switching from positive ground power to charge pump power. The circuit operates just fine in positive ground mode. Double checked all wiring and grounding and cant seem to find a single thing wrong. Has anyone built a charge pumped rangemaster and had good results? I would really like to get these OC44's working in the circuit but I guess I will go NPN if all else fails. I am thinking the rangemaster is having some kind of strange reaction to the charge pump but don't know what specifically.

[pryde]

Hello.

I built a RM with an OC44 and a road rage with no issues at all. Not sure what I can do to help but glad to take any measurments, etc you might need. Here are a couple pics if it helps:

[JakeFuzz]

Thanks Pryde. It is just good to know it works and that I must be laying something out wrong. Did you wire up the RR with just three caps for -9v operation? What type of charge pump did you end up using?

[jimmybjj]

just taking a stab in the dark. If your using a 1044 did you connect pins 1 and 8 to boost the oscillator frequency?

[JakeFuzz]

just taking a stab in the dark. If your using a 1044 did you connect pins 1 and 8 to boost the oscillator frequency?

Yep Ive got those connected. Very weird problem. I am rebuilding it on vero and using one of Keefe's inverter boards right now. We'll see if that helps.

[alanp]

I've got one of them things in my Rangemaster. You can use vero, the chip, and two caps for not much bigger than the IC itself.

[pryde]

Thanks Pryde. It is just good to know it works and that I must be laying something out wrong. Did you wire up the RR with just three caps for -9v operation? What type of charge pump did you end up using?

Yes I just populated it for -9v operation and used a 1044SCPA. Somewhere along I think I read that it should be an SCPA and not CPA. Not sure what you are running.

[Scruffie]

Well... We can assume it's the power for now. Try a 100R in series with the power with a filter cap if you don't have one, then an extra filter cap after the charge pump if there isn't one.

[JakeFuzz]

Weird, so i went to a dedicated inverter board and a separate vero rangemaster board and it sounds fine now. Very strange. Maybe I was getting cross coupling between lines? Any ideas why this little compressed layout wouldn't work? (note that there is an additional capacitor on the +9v line off the board) Maybe i've missed something... 

[mandrewbot3k]

Weird, so i went to a dedicated inverter board and a separate vero rangemaster board and it sounds fine now. Very strange. Maybe I was getting cross coupling between lines? Any ideas why this little compressed layout wouldn't work? (note that there is an additional capacitor on the +9v line off the board) Maybe i've missed something... 

looks like youre missing all the diodes from each individual circuit also. probably just extra noise.

move c4 over to column 9 and throw in the missing D1 1n4001 on the -9V to ground? not sure if that would cause your problem or whatever, but just me looking through the schematics.

And a missing ground lead (i assume thats on there somewhere, row j?

i dont think this matters, but to be more literal r3 would be on the other side of q1, between r1 and q1. Don't think that matters at all though. same bus.

And not really sure about this, but do would you need the sag trimpot on pin 6?

[Scruffie]

Weird, so i went to a dedicated inverter board and a separate vero rangemaster board and it sounds fine now. Very strange. Maybe I was getting cross coupling between lines? Any ideas why this little compressed layout wouldn't work? (note that there is an additional capacitor on the +9v line off the board) Maybe i've missed something... 

move c4 over to column 9 and throw in the missing D1 1n4001 on the -9V to ground? not sure if that would cause your problem or whatever, but just me looking through the schematics.

And a missing ground lead (i assume thats on there somewhere, row j?

i dont think this matters, but to be more literal r3 would be on the other side of q1, between r1 and q1. Don't think that matters at all though. same bus.

A polarity protection diode missing shouldn't cause an issue.

I stand by my remark about the series power resistor, they can help a lot with charge pumped germanium builds, the added power filtering stops artifacts from the MAX1044 & Power Supply... it may be the added wire of having it on a seperate board connecting them over is effectively working as a small resistance.

I think somewhere I have a vero layout for the rangemaster in a 1590B with the MAX1044 & 2 Trimmers on board and a board mounted pot (standard mounted, not right angle) if it's of any interest... wouldn't be any more than 21x8 holes, which is about as much as I recall you can cram in a 1590B like that. Of course I may not, I just know I did that sort of layout for a few old Ge Fuzzes some time ago.

[JakeFuzz]

Thanks guys! Yeah Rofl, I usually leave out the reverse polarity diodes to save space on these 1590a layouts. Living on the edge    I did forget to show the ground connection. You could do either J or D, I actually separated them at one point to see if that made a difference. I am 99 percent sure the connections are in the right places just a odd problem i've never had before.

Scruff, that is what I am thinking too about the decoupling for each board. I could probably add a ton more filtering to try and lower the noise floor. The CP board and RM vero barely fit in the 1590a right now. The OC44 sounds good too, not as dark or fuzzy as my OC140 RM. Another successful addition to the 1590a mini board!

[Scruffie]

Thanks guys! Yeah Rofl, I usually leave out the reverse polarity diodes to save space on these 1590a layouts. Living on the edge    I did forget to show the ground connection. You could do either J or D, I actually separated them at one point to see if that made a difference. I am 99 percent sure the connections are in the right places just a odd problem i've never had before.

Scruff, that is what I am thinking too about the decoupling for each board. I could probably add a ton more filtering to try and lower the noise floor. The CP board and RM vero barely fit in the 1590a right now. The OC44 sounds good too, not as dark or fuzzy as my OC140 RM. Another successful addition to the 1590a mini board!

Ahh, 1590A, my bad  forgot to re-read the first post.

I don't think you need a ton more filtering, that series resistor will form a low pass filter with the power supply cap and in a treble booster... give it a go next time and should it not work pre MAX, try it on the Rangemasters 47uF.