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Vintage threads from the first ten years

EH Small Stone help....

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5/1/2000 5:13 PM
Ian Anderson	EH Small Stone help.... When the effect is activated there is a slight loss in volume - anyone have any ideas on how to remedy/mod this? It's an 'issue J' version if that helps at all. Just thought I'd start on this since I opened it up the other day after the 'Color' switch got busted-up in my (overcrowded) gig bag. Cheers... Ian

5/3/2000 3:29 AM
John S.	Re: EH Small Stone help....x 2 Mine does this also! I have a "J" series Small Stone also,and it loads down when it is engaged.....Mine at least has the DPDT true bypass switch in it,but I not only notice a volume drop,but also a slight loss of high end with mine.....I'm interested in the replies on this also....Please help us....LOL.Thanks John S.

5/3/2000 4:08 AM

Sorry guys, I can't really help you out, but I can give you a condensed history of posts I've seen on this subject. Basically this is a commonly reported problem with originals and reissues. I have two orignals and they both have a slight loss of volumne when engaged. I replaced the 25 year old electro caps in mine, but that did not correct the problem. IMHO, the best advice given so far is to add a small DIY fet booster circuit with adjustable gain at the input of the unit. The volumne loss on my units is not enough to bother me so I've kept mine stock.

JD

5/3/2000 1:49 PM
John	I came here today to post this exact question about an original orange graphic one I just got. With the color switch up it no longer sounds like a guitar and I lost all strumming sounds. I noticed that the more color the more loss of highs (and that you can get in-between settings by sliding the color switch). How can you tell what series each pedal is from and what is the significance?

5/3/2000 3:25 PM
JD Sleep	>>How can you tell what series each pedal is from and what is the significance? Look on the PCB itself to see the issue designation. I think the orange letter version is the issue J. I would start by checking the color switch itself, see if replacing it fixes the problem. JD

5/3/2000 8:24 PM
John	"I would start by checking the color switch itself, see if replacing it fixes the problem." This was a good thing; I have more than two options of color. It acts as a pseudo-pot.

5/3/2000 3:44 PM

Re:Small Stone loss of volume

The loss of volume when engaged is correctable in the Issue J Small Stone by changing the gain of the two-transistor preamp at the input of the circuit.

There are two 4.7K resistors at the emitters of the input transistors. One goes to ground from the emitter of Q1, the second connects the emitter of Q2 to the emitter of Q1. Those two resistors set the feedback gain of the two-transistor compound.

Increase the 4.7K between the emitters to increase the gain. Start with 10K. Be aware that this will affect the stage biasing, so the headroom may be affected; I don't think this will really be a problem.

The silly thing *ought* to have included a JFET buffer in front of it for buffered bypass and a bit of gain in the first place.

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