Pot Specs in Express

[MGW]

So I'm getting everything together to start the Express build. I'm sure it's been talked about, but I couldn't find it. Are the 2 watt pots really necessary or is that wreck mojo? The reason I ask is that all I can find in 2W is the stainless PEC stuff and the $15 a pop Alessandro's. Of course what I really want to use is the 1 watt Alessanrdro pots for $37.50 each!

Seriously though...are 2 watt pots necessary?

[M Fowler]

They are not necessary but if you want PEC pots they are $9.95 at

http://www.tubesandmore.com/

under potentiometers then click on Precision Electronics.

Mark

[Lonely Raven]

Consider the 2 watt pots "industrial" grade that can hold up to regular gigging and will probably outlast you. If you're building a keeper amp, $10 a pot is a small price to pay to have an amp you will give to your kids in your will.

[M Fowler]

Especially when there is only five pots to buy.

I don't use PEC I use Alpha and CTS myself.

Mark

[MGW]

The PEC pots cost isn't the issue, it's the stainless case. I can actually get the pots for just under $8 a piece. That being said, I don't want to put stainless in there and that is because of the ground buss.

Mark, are you just using 1/4 watt pots in yours?

[selloutrr]

A few actual Wrecks used Stainless pots. The ground bus then connected to a ground lug and bent behind the pots. The pots are wired to the ground bus with short jumpers.

Most clones use ground lugs that fit around the shaft of the pot seated between the chassis and potentiometer. Then bend them at a 90 degree angle and run the bus wire thru the holes. No soldering directly tot he stainless pots.

If you want to solder to the back of the potentiometer. Use Alpha, CTS, or Centrlab potentiometers.

[M Fowler]

Mark, are you just using 1/4 watt pots in yours?

Yes I just use the standard Alpha, CTS or Bourns pots sold by many amp parts dealers.

I have used the ground tabs mentioned as well.

Don't over heat the pots when soldering.

Mark

[Cliff Schecht]

So why not solder to the back of stainless pots? I've had really good luck with gently removing the coating from the back of Allen-Bradley style 2W pots (the J-series guys) with a dremel, putting down a bit of flux and flowing solder right onto the back of the pots. You can test the strength of the joint by hitting it hard with a flatblade screwdriver. If it comes up or off in any way then you didn't get a good connection. I actually have quite a few amps that use this method and they all sound great and have held up just fine..

With that said there is nothing wrong with using ground tabs. I use 'em too when I have them.

As far as brands, my personal amps are always a mutt when it comes to pots. I'll use whatever I have on hand, be it Alpha, CTS, Centralab, AB or PEC (did I get them all?). If they don't scratch loudly when I turn them then I'm happy.

[Lonely Raven]

You forgot Bourne.

I'm trying some out in a 5E3 build that I keep putting off.

[diagrammatiks]

which bourne ones? the standard non-sealed?

i've been seeing some good things about their 95 series sealed pots.

I really like stainless steel sealed pots...but honestly I don't like the quality of the PEC ones at all.

The old USA/Mexico A/B Clarostats are sturdier by far.

[Lonely Raven]

which bourne ones? the standard non-sealed?

i've been seeing some good things about their 95 series sealed pots.

I really like stainless steel sealed pots...but honestly I don't like the quality of the PEC ones at all.

The old USA/Mexico A/B Clarostats are sturdier by far.

Whichever ones ApexJr has. Since the 5E3 is just three 1MA pots, I bought some PEC, and Bourne and Alpha to see what I like the best.

[diagrammatiks]

oh nice. steve has surplus of the 1meg-log a/b and claropots.

those are my fave.

[Cliff Schecht]

Same here, I love the old AB and Clarostat pots the most. So sturdy!

[greekie]

FWIW, the ground bus on the back of the pots make a horrible ground loop that is the source of noise in many amps. I can only recommend that you connect the pots casings to ground through the chassis only, and keep the bus floating behind the pot cases.

YM2C.

Jake

[M Fowler]

Jake,

Speaking of that ground loop. I am going to drill out my Liverpool pot holes and use plastic inserts and fiber washer to isolate the pots and then use ground tabs and isolate the input jack to see what that does in a TW.

I want to completely rebuild my Liverpool anyway.

Mark