Dual ganged rheostats?

[Chuck H]

Anyone know where to find them?

Tia

Chuck

[Old Tele man]

...using the word "rheostat" instead of "potentiometer" implies you want to handle some power rather than signal voltage...correct?

...making an "L-pad" attenuator?

...try anyone of the BIG electronic wharehouses, such as Mouser, Allied, Newark, State Electronics, etc.

[Chuck H]

Thanks OTM, but I dind't post before checking around quite a bit. I'm still looking though. I see them mentioned in the course of project discussions but I can't seem to locate any. I did see some once upon a time on a electronics salvage site. But the values were slim pickins'.

And yes, I'm building an L-pad (sorta). A friend wants a custom stereo amp with all ganged controls and a built in attenuator.

Chuck

[uvacom]

So just get dual potentiometers. The pickings are far from slim.

dual

[gmoon]

Will a regular L-Pad work? A few of those are stereo l-pads...

[daz]

I entered "dual ganged rheostat" in google and found quite a few. But not knowing exactly what you want i don't know if any of them would fit your needs. Try radio shack too....i could swear they used to have a stereo one when i looked at rheostats there a few years back. No idea what value tho.

[Chuck H]

So just get dual potentiometers. The pickings are far from slim.

Thanks for the reply and the link. But how does a standard potentiometer replace a rheostat?

Chuck

[Chuck H]

Will a regular L-Pad work? A few of those are stereo l-pads...

Thank you. But have you ever seen what a regular commercially sold "L-Pad" does to your amp on a scope? I have my own design that works much better. But I need a dual ganged 25 or 50ohm@50watt to do it.

Chuck

[Chuck H]

Thanks daz, but for some reason when I type "dual ganged rheostat" into google I get five links that only mention the use of a dual ganged rheostat and some peripheral links for single units.

Chuck

[daz]

I'm sorry, try "ganged rheostat". Eliminating the word dual yields far more hits. And make sure to use the quotes untill you've exhausted all the possibilities in the results when using them. It will eliminate a million hits that are less relevant.

[Chuck H]

OK... You know what? I just plugged "dual rheostat" into google and found some salvaged parts. Nothing of the right value and sometimes obscenely overpriced but it gave me a clue as to why I'm not finding new units. The rig for a dual ganged unit is just a frame around two single units with a chuck that joins them shaft to rear. I have a couple of units here and looking at them I think I can fabricate something. I'll also write to Ohmite and see if I can just get the kit that does it. It'll work out.

Thanks for all the replies.

Chuck

[dai h.]

hey Chuck, it might be easier and more sensible to use a fixed L-Pad, then follow that with something so-so high and more easily obtainable (at spk. parts places, etc.). (My memory from websearching stuff on attenuators is a bit foggy, but) I think it made more sense to have a fixed L-Pad before for safety, since the rheostat is (what I think is called) an "electro-mechanical" part (which can wear out and go open). So even if the rheostat is a super high quality part and the wearing out happens in the (very?) long run, when that situation is (assumedly) eventually encountered, the (OT) secondary isn't left open if the dual rheostat is the only thing between the amp out and spk(s). (probably makes sense to have the mod Bruce mentioned found in Vox of a high R on the highest OT second. tap for safety). Plus, if the (custom? or super difficult to source) high power dual rheostat (I'm assuming/making an educated guess that the goal here is to handle a wider range of power than typical off-the-shelf variable L-Pads) is to handle a wide attenuation range, I think the thing to consider is--do you REALLY need that wide a range, esp. if say, most of the time heavy attenuation is used (that is, in a more-or-less restricted range)? If cost isn't an issue then I guess it doesn't matter but possibly you could organize some group buy (qty. purchase) type thing with people of similar interest to help lower cost.

[uvacom]

Thanks for the reply and the link. But how does a standard potentiometer replace a rheostat?

Chuck

Because a rheostat is just a potentiometer without one of the terminals. A lot of rheostats are specifically designed to handle large power, but then, so are some potentiometers.

[uvacom]

Oh, I just read the 50W part. Hmm. Not too many pots that can handle that kind of power.

[dai h.]

right. He needs something for power and something not ordinary if he needs a high power L-Pad. An L-Pad is also two pots of different values (series and shunt IIRC) inside one enclosure (one is a "usual" impedance such as 8 or 16, while the other is much higher in value). I think once you go beyond the usual offerings (that is, higher than around 50watts power handling) looking at places that sell speaker network parts, the pickings are slim or non-existent.