RM Treble Booster & Pull Down Resistor

[thermionix]

Through trial and error I think I got it working in a way I like, it sounds great.

So what did you do with the output pulldown?  Omit it?  Are you getting bypass switch pop?

[Ben Lyman]

I did not use a pull down on the output and it does pop but my brother will have to live with it that way, it was another gift for another brother. When I tried a pull down on the output it totally eliminated the possibility of having a Tone Bender after it, which was very important in this case. I did use a 2M2 on the input with no ill side effects.
The input cap switch works like a charm and all 3 positions are very good, the bass boost is especially good with the MKII to get thick metal tone.
I wish I could play with it some more but he came and took it already today... time to make my own... I'm thinking one enclosure that holds a RM and MKII with two foot switches and all the knobs

[Gus]

What value control did you use for R4 the volume control?

Did you try a different C6?  The cap might be bad.

Why did you use a .01uf output cap instead of a .1uf or larger?

[samhay]

>Why did you use a .01uf output cap instead of a .1uf or larger?

10n is the stock value for the Dallas Rangemaster.
If the circuit is used to directly feed an amp - as designed - or another pedal with a 'modern' input impedance of ~1M, then its LPF corner is low enough for any sensibly-tuned guitar.

or are you playing Socrates again Gus?

>When I tried a pull down on the output it totally eliminated the possibility of having a Tone Bender after it, which was very important in this case.

This doesn't make sense unless you wired the pulldown resistor in a rather unconventional way.

[Ben Lyman]

What value control did you use for R4 the volume control?
Why did you use a .01uf output cap instead of a .1uf or larger?

I used a 10k pot like the stock RM and the 10n output cap was the one in the original schematic. Maybe I should have tried a larger value, never thought of that, I wonder if it would change the tone much. Thanks Gus, this one is done but I will be making another soon.

>When I tried a pull down on the output it totally eliminated the possibility of having a Tone Bender after it, which was very important in this case.

This doesn't make sense unless you wired the pulldown resistor in a rather unconventional way.

Thanks, I just put a 1M at the output to +9v... or did I? maybe I accidentally put it on -9v  or I might have done the tone bender in an unconventional way with a 1M pull down at the input, could that have had a bad reaction?

[samhay]

Is it negative ground or positive ground? Running of battery or DC?

[Ben Lyman]

Is it negative ground or positive ground? Running of battery or DC?

Pos ground like the original, battery only. I boxed it up yesterday and my brother grabbed it and ran before I could shoot a vid but here's the pics:


 

[thermionix]

I boxed it up yesterday and my brother grabbed it and ran before I could shoot a vid but here's the pics:

I'm curious about the cap on the 3PDT.  Is that to reduce switch pop?  Fill me in, good brother.

[Ben Lyman]

That's the 10n output cap coming from the wiper. I could've put it on the pot itself and ran the wire to the 3PDT but in my haste I wired everything up and forgot it... so there it is at the end of the wire going onto the switch 

[antonis]

Just to add a practical discrimination on RG's well said analysis..

We often use the term Common Emitter when there is an emitter resistor (Emmiter degenaration) & Grounded Emitter when there isn't such a resistor (Emitter with no degenaration)

[Gus]

That's the 10n output cap coming from the wiper. I could've put it on the pot itself and ran the wire to the 3PDT but in my haste I wired everything up and forgot it... so there it is at the end of the wire going onto the switch 

You posted a schematic before that does not have the bypass switch in it. 
Draw how you wired the output cap with the switch this will help. 
What are the resistors on the switch for?

A 10K volume should not have an issues with driving most effects after it if they have a high enough input resistance. 

[Ben Lyman]

The 10n output cap goes b/t A10K pot wiper and (top right corner) lug of switch.
Those are 0 ohm resistors on the switch, one for bypass and one to ground the board input.
Is it possible that my (otherwise stock) Tone Bender 1M pull down resistor made the two pedals incompatible?

Since pulling the 1M pull down out of the RM output, no problems at all with the Tone Bender after it. And it was only the Tone Bender that was incompatible before, Electra and compressor worked fine with the RM.

My brother played it all day/night yesterday into his 1950 MASCO MN-17n and texted me this quote later that night:

"Cranked the masco full with the range master/tele,
words can't describe! Awesome doesn't sum it up.
PERFECT. That's all I can say;
anyone into vintage country tones would agree."

[Ben Lyman]

I just BB'd another RM, NPN this time with Ge 2N1304, all components are equal to the PNP version and it sounds just the same, works great, it's gonna be a keeper. I will be giving this one the full treatment, power filter, LED indicator and DC power jack in addition to the battery.

Here's the weird (or normal) part: I put 1M in and out pull downs, plugged in the Tone Bender and it all works fine. I even tried moving the pull down to some wrong places but I could never duplicate that weird problem I got before. Maybe the 1st RM had a bad output cap. The Tone Bender does have an electrolytic input cap with the pos side towards the input and the neg side towards the Q1b just like in the schematic, I don't know if that cap was doing something weird withe the PNP RM plugged into it. Something that this latest RM w/NPN doesn't do...
oh well, it sounds great and it's got pull down resistors on in and out. Is it better to have a big pull down on the input and a smaller one at the output?

[antonis]

Is it better to have a big pull down on the input and a smaller one at the output?

As a general idea, it's correct but it depends on the specific circuit..

If the small resistor "loads" the Output pot (Volume) you may have problems..
(I'm not talking about Volume pot at the end of the circuit because in that case the total resistance of the pot plays the role of pull-down resistor..)

A good idea is to ground the output via the 3PDT switch in By-pass mode...
(I always do it for In & Out despite of pull-down resistors existence or not..)

[Ben Lyman]

Thanks Antonis. I have the input grounded on the switch but how can I ground the out put as well? Is that even possible or should I forget about grounding the input and just do the output instead?

[antonis]

Ben, you can obtain it in many ways..

Here is a couple of them but you can always try your own wiring..
(it has a lot of fun.. )

[Ben Lyman]

Thanks again Antonis! That's the cure, I had such a hard time visualizing how to wire the switch so in and out both get grounded but now I get it. My NPN RM with all the modern features is up and running, been playing it for a few days now, no popping, sounds great, 3 input cap modes gives classic RM boost, my own "less treble" boost or bass boost which can make an OD or tube amp sound like a heavy metal machine. My "less treble" is the perfect mid boost for lead guitar solos without such a drastic tone change as the stock setting. I really like the stock treble boost with my RC Compressor for super snappy-twangy country pickin'
pics here:
http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg1055389#msg1055389