Build Ram's Head with current NYC Muff?

[Guitarfreak]

Is it possible given the NYC circuit board and modern components to build a vintage Ram's Head muff?  I understand that the Ram's Head was PNP, would it be possible to build a clone using NPN instead? The schematics look exactly the same save for the component values.

[theehman]

Is it possible given the NYC circuit board and modern components to build a vintage Ram's Head muff?  I understand that the Ram's Head was PNP, would it be possible to build a clone using NPN instead? The schematics look exactly the same save for the component values.

Contrary to what you may have read/heard, a vast majority of them are NPN.  PNP Muffs account for ~5% or less of all Big Muffs that I've seen.
So the answer is yes, it can be done.  I do it when a customer requests it.

[Guitarfreak]

Is it possible given the NYC circuit board and modern components to build a vintage Ram's Head muff?  I understand that the Ram's Head was PNP, would it be possible to build a clone using NPN instead? The schematics look exactly the same save for the component values.

Contrary to what you may have read/heard, a vast majority of them are NPN.  PNP Muffs account for ~5% or less of all Big Muffs that I've seen.
So the answer is yes, it can be done.  I do it when a customer requests it.

That is great news!  How does it sound?  Does it compare to the vintage units?

[theehman]

No complaints yet.

[Renegadrian]

A "customer" (he'll pay me a couple of drinks for the work) wants me to mod his NYC (EC3003 rev.c) to the Ram's head - I am trying to spot the differences...I have seen some schems, using 2n5088s, while this unit has bc550s...but they should be quite similar I guess...I see a difference at the input el. cap (1µ-10µ) - which are the other differences?! Should I change the 500k pot to a regular 100k?! Anyone!?

Also, he wants me to build a second circuit to fit in (russian) with a shared tone pot - do you think it can be done and how?! just sending the two sets of wires to the same pot?!

[Scruffie]

A "customer" (he'll pay me a couple of drinks for the work) wants me to mod his NYC (EC3003 rev.c) to the Ram's head - I am trying to spot the differences...I have seen some schems, using 2n5088s, while this unit has bc550s...but they should be quite similar I guess...I see a difference at the input el. cap (1µ-10µ) - which are the other differences?! Should I change the 500k pot to a regular 100k?! Anyone!?

Also, he wants me to build a second circuit to fit in (russian) with a shared tone pot - do you think it can be done and how?! just sending the two sets of wires to the same pot?!

I can answer your second question, just use a dual ganged pot.

[azrael]

A bunce of differences, collector resistors on Q3 and Q4....Feedback resistors on Q1 and Q4. Emitter resistors on all of them, coupling caps, the low pass filter caps in Q1-Q3...plenty of differences.

[Electric Warrior]

and plenty of different ram's head versions 

[theehman]

and plenty of different ram's head versions 

+1 on that.

[Renegadrian]

[yeeshkul]

The best thing you can do is to borrow Ram's from someone and stitch it up to the sound. That is what i have done. You have to tweak the sound so it works well with the newer transistors that are in NYC units. I ended up with 220n input cap and really small emitter resistors but there is no recipe for that. Also Ram's used to differ a lot so the whole thing is kinda ambiguous . And one more thing - when you copy a real Ram's don't forget that the elyte caps may have dried up so it actually doesn't sound the same as in 70's. You have to measure them to see if they are still in their tolerance range. That is a thing people underestimate.

Sending two pair of wires to the same pot is not the best thing you can do. The resistors in the grid around then get in parallel with the other unit and get half a size in total. And other things.

[Renegadrian]

As for the tone pot, I guess he wants a shared pot, but only one setting, so no need for a dual ganged (I think)
Is it possible to use a regular pot with two circuits?!

[Guitarfreak]

As for the tone pot, I guess he wants a shared pot, but only one setting, so no need for a dual ganged (I think)
Is it possible to use a regular pot with two circuits?!

I would wire a DPDT with the tone stack caps soldered directly to the switch throws and wire them into the correct PCB spots.  That way you get Ram's head in one position and Russian in the other position.  The tone stack anyway.

[azrael]

As for the tone pot, I guess he wants a shared pot, but only one setting, so no need for a dual ganged (I think)
Is it possible to use a regular pot with two circuits?!

You're thinking of a concentric pot, which has two concentric knobs, each controlling a different taper.

A dual ganged pot is only one knob that controls both tapers.

[Renegadrian]

As for the tone pot, I guess he wants a shared pot, but only one setting, so no need for a dual ganged (I think)
Is it possible to use a regular pot with two circuits?!

You're thinking of a concentric pot, which has two concentric knobs, each controlling a different taper.

A dual ganged pot is only one knob that controls both tapers.

got your point, thx!