Rangemaster - Modern germanium transitor equivalents?

[kleuck]

The input resistor is fine, but the output on should be tied to the circuit output, right after the 100 nf cap.

[tubeswell]

Thanks kleuck - I did wonder about that .01uF (in terms of how to treat the audio path going to the output) - corrected version attached (with pretty colours)

[kleuck]

And 2M2 is pretty high for this circuit -low values=less pop, usually you can't go too low, cause you lower the input impedance too.
The RM input impedance is very low, so 500 K or 1M would be enough on the input, on the output 100 k is enough.
And you don't want to power down the circuit when switching the effect off, no circuit can be biased and start instantly, so you ill have a lot of noises when using the switch.
You'd better wire a true bypass Many Bypass Switching Options

[tubeswell]

Many thanks for that handy link kleuck. I'm eternally grateful. This is how I interpret your suggestion. (The battery is supposed to be wired through a switch on the output jack with this DPDT switch, but I acknowledge I could use a 3PDT switch in that regard).

[kleuck]

The input resistor should be soldered right before the input cap of the circuit.
Here's a modernized clone : http://diy.musikding.de/images/stori...angeschalt.pdf
Beware, it's a negative ground one (but you can build the same way, the Beano is a negative ground too)
Usually there's no power switch in pedals, you just need a stereo jack at the input : http://www.generalguitargadgets.com/...8044a841b3e85a
When there's no jack plugged, the battery is off circuit (no connection to ground)
Beware, this is a generic negative ground schematic, if you go positive ground, the "+" from the battery has to be tied to the ring of the jack.

Here a positive ground clone : Rangemaster

I realized i did a mistake : i use 1 µf output cap, but if you use a 10nf one, the output resistor should be high, to avoid too much low loss from the output, so stand with 1M or 2M2.

[Regis]

Pete, keep us posted on the construction of your RM, I just bought an OC44 for my RM build.

I just bought an AC30 and a Rangemaster is the 2nd part of the three part Brian May equation.

[tubeswell]

Okay I wired it up today but something is not right. I'm getting -.66V from (what I believe is*) the emitter to ground using a battery that measures 8.8VDC. (The base to ground measures -.77VDC) There is -8.67 VDC between the power rail and the ground return with this battery. The emitter resistor and the leg of the base bias voltage divider are pots wired as variable resistors for tuning purposes. The emitter resistor is set at 3k9. The base voltage divider is set with a knee at 470k (a fixed resistor) and the 68k setting on the pot. (Schematic attached)

When I use a battery that measures 9.56VDC, I get -.74VDC from the emitter to ground (and -.85VDC from the base to ground). There is -9.55VDC from the power suply to the ground return with this other battery.

I understand the emitter it is supposed sit at around -7VDC.

Everything is wired as it should be AFAICT, (i.e.: with +ve ground return, and battery -ve to power supply. Both filter caps are +ve to ground return and the resistors and caps are where they ought to be in relation to each other.

*based on what I understood JM Fahey to have explained about the three wires coming out of the bottom of the OC44.

So what is this? A dud OC44?

[kleuck]

It's not the emitter which is supposed to be at -7v, but the collector.

[tubeswell]

Whew! Thanks Klueck -7.2 at the collector.

Coool - I just tried it with one of my tube amps - bit late here at the mo' so I couldn't really wind it up. Looking forward to jammin' with it tomorrow. I must say it is very cool

[J M Fahey]

something is not right. I'm getting -.66V from (what I believe is*) the emitter to ground

That's whatyou must have there.
-7V there would mean a very dead transistor.
Good luck.

[tubeswell]

Some pics

FWIW I designed the layout using the 'do it as you go' method i.e.: I pre-assembled the board first, and the juggled the bits around to get the best fit. (Now I just have to think of some pic to put on the front).

[tubeswell]

I took it gigging last night with my PR clone. Wicked combination. I'll have make some soundbytes