Help fixing volume level differences in a Small Stone

[shawsofhell]

I built the tonepad small stone about a year ago and have put up with the volume loss problem since then. I have decided enough is enough and that I should fix this. I know there are several ways to fix this but I hear some may cause oscillation problems. Can some one give me a good way to fix the volume drop between bypass and on and also the volume difference between normal and colour modes?

Also I was wondering if anyone had a good mod to control the intensity of the feedback in colour mode?

[shawsofhell]

please anyone?

[moosapotamus]

How about a simple booster on the output (between the PCB output and the stompswitch). I've used the stratoblaster with great results, but you can pick your favorite flavor.

~ Charlie

[shawsofhell]

What about the slight volume drop between colour and normal mode?
Is there a simple resistor change?

[aron]

Does this thread help?

http://diystompboxes.com/sboxforum/viewtopic.php?t=32849&highlight=stone+vol+volume

[shawsofhell]

:oops: Now I feel stupid I didnt see that one when I originally searched the forum.

Thanks Aron!!!

[shawsofhell]

Ok that actually wasnt that helpful since that is another version. There are no resistors in the tonepad version with those values.

Maybe if I just put a buffer in front, but then there will still be a difference between normal and colour modes.

[Fp-www.Tonepad.com]

A buffer won't help.

You should add something like an LPB1 between the pcb's OUT pad and the stomp switch, then preset the volume with a trimpot or drill another hole in the enclosure for a regular sized 'boost' pot.

Fp

[bassmeister]

I've had several problems with this design too, i.e. volume drop when on, more volume drop when the color switch is on, LFO clicking, more clicking when the color switch is on. The first three problems were fixed thanks to this forum, the last one I figured out on my own (didn't find anything about this in the archives and no answers when asking on this forum . No, really, I'm not bitter. I've recieved much help and inspiration here regarding this and other matters)

Fixing the general volume drop

Does this thread help?

http://diystompboxes.com/sboxforum/viewtopic.php?t=32849&highlight=stone+vol+volume

Follow the link (http://www.generalguitargadgets.com/bom/smallvlp.txt) in the first post. Read the third paragraph, starting with "From R.G. Keen". His component designators and values match the Tonepad version. Performing ths mod first of all should result in a whining when the color switch is on (too much feedback)

Fixing the "more volume drop when the color switch is on" problem:
Increase the value of R10. I had to put 100k here to eliminate this problem. I'm not sure if this high a value removes almost all feedback and what I hear is just the change in sweep range when I change the color switch position (which is what the color switch does, changes the sweep range and feedack), but it sounds good in my ears, so... This mod also decreases the feedback, but I thought it was way too much anyway to be useful. I also lowered the feedback even more by increasing R11 in the resistive divider network (R11/R12). Find out more in this thread (http://diystompboxes.com/sboxforum/viewtopic.php?t=22881). When I did this mod, the clicking LFO was really audible when the color switch was on, even at low amp gain. But wait, read on...  

Fixing the clicking LFO
The PDF document at Tonepad with the schematics over this design shows where to put a relatively small cap (Ca) in the LFO section to eliminate the clicking LFO. Remove it and you will probably hear a click at the endpoints of the sweep. Increase it and the click will be eliminated. However, Ca is disconnected when the color switch is on, but C10 is connected where Ca used to be when the color switch was off. I increased C10 and the clicking disappeared. Seems quite obvious, but I was very blinded by frustration over the click before I came up with the solution. I'm not sure what really happens since I don't know how the LFO section works, but it worked.

These mods has resulted in a perfectly silent, click free and great sounding phaser. It colours the sound more than my MXR Phase 90, but in a good way. And, during my the-click-must-go journey it turned out that the Phase 90 has a muffled click when the gain on the amp is high. Not so with the Tonepad Small Stone . This is important to me since I like the sound when a distortion is put after the Small Stone.

[shawsofhell]

If I put the booster on the input of the phaser would this give me a percieved more intense effect? I know this may create distortion but I doubt at the small level of boost I need.

[petemoore]

If I put the booster on the input of the phaser would this give me a percieved more intense effect? I know this may create distortion but I doubt at the small level of boost I need.
 You can try. After trying both positions, I put the booster after the SS because of the distortion.

[aron]

Thank you Bassmeister!

ARCHIVE

[bioroids]

Hi!

I also had the color switch volume loss, I fixed it by changing R11/R12, then I realized it would have been simpler just to increase R10. This is using Tonepad version.

What happens (I think) is that switching the feedback ON also has the effect of reducing the impedance of the first stage to something like R10+R12 (31k7, comparing to R9=270k when the switch is off, all this in parallel to the stage Z). To make matters worse there's a 100k resistor R4 before the stage, so that would explain the volume loss. I lowered R4 to 47k just to increase a little the general level.

On the general volume loss, I increased R42 from 4k7 to 5k6 to fix it somewhat. I originally used 10k, and was better, but introduced noticeably distortion with the treble setting on my SG.

Regards

Miguel