Pots with roughly 30% taper?

[Mark]

Hi

I kind of feel like the man from La Mancha at the moment.

When it comes to tone controls in amps and how effective they are, my 6G7a Bandmaster is king. Just for the hell of it I measured the taper of both pots. The bass pot is 250K pot with a 10% taper, not a problem as they are easily obtainable. The magic is in the 350K tapped pot. The taper in the 350K pot is 30%, that's a problem as these aren't obtainable. I know Fender did have a 250K pot with a 2-35% taper which is no longer in production, I'd imagine this would have worked very well too.

Do you guys know anyone who sells 30% taper pots?

I believe Weber sells 20% taper pots, but I'm not sure thats going to cut it.

Mark

[HotBluePlates]

According to Weber's site, it's:

"350K Audio tapped at 70K from the CCW end"

They also say, "Audio pots are 10% or 30% audio taper as noted," except that for most of the amp pots it's not noted. They do mention when guitar pots are 10% or 20% taper (and I only see 20% taper in guitar pots).

Send em an e-mail and ask about the taper of the tapped pot. Since they probably special-ordered those anyway, I'm guessing it's likely a good match.

Regardless, you might as well call a 30% taper "linear-lite". Used as a volume control, it comes up maybe too fast, making some people think their amps are really powerful when they only dial up to 2 ("WoW! Look how loud it is on 2!"), or make some tweed clones sound like they have no headroom.

You'll get slower/smoother volume-increase with a 10% taper.

[Mark]

Thanks for the reply.

I have already bought the 350K pot and the it's a 10% taper, which is unfortunate.

I did post a question at Ted's forum but I haven't heard back from them.

Mark  

[HotBluePlates]

So you had a functioning 350k tapped pot before?

Can you describe the difference in response? I'm assuming you tried to recreate this stack in another build, is that right?

Maybe e-mail WeberVST and tell them the difference. Since they are probably one of the few special-ordering it from Alpha, they'd be in the best position to get it modified.

[Geezer]

What's the taper of the one Doug sells?

[HotBluePlates]

Dunno.

I had a good look at Alpha's website, and it's possible to get this pot with a custom tap point and any taper from 10%-30% audio, and several in-between.

No idea what the minimum order quantity is, but I bet it's a lot.

[jazbo8]

Here is a "fake" taper using a linear pot and a resistor based on the secret life of pots at http://www.geofex.com/Article_Folders/potsecrets/potscret.htm

here is 350K pot with a 50k resistor:


it may not sound/work the same as it loads the driving circuit, because "neither the load seen by whatever drives Vin or the source resistance as seen by the input of whatever is connected to Vout is close to what would exist for a real log pot of value R...", but it might be worth a try though...

Jaz

[PRR]

You *may* be able to bend taper.

But isn't Mark asking about 6G7a Bandmaster's tapped pot?

Tapped pots are rare in guitar work. They were common in fancy radios and hi-fis, to bring up bass (maybe treble) at low listening levels for a more full sound. The Fender 350K is a relic of the days when stereo displaced mono and surplus tapped-mono loudness pots were dumped on the market.

[Mark]

All the treble pots I see in Dumble circuits are the old Fender CTS 2-35 250K pot. I mention the 350K pots as I have an amp with these pots in them and it sounds great.

I'm actually after a 250% pot with a 30% taper, but they are impossible to get. I believe CTS can still make them, but no one has placed an order. I dare say the pots will eventually sell, but it is a long time to have inventory/money sitting around.

I've attached the CTS catalogue.

Mark

[jazbo8]

You *may* be able to bend taper.

But isn't Mark asking about 6G7a Bandmaster's tapped pot?

Tapped pots are rare in guitar work. They were common in fancy radios and hi-fis, to bring up bass (maybe treble) at low listening levels for a more full sound. The Fender 350K is a relic of the days when stereo displaced mono and surplus tapped-mono loudness pots were dumped on the market.

Yup, I need better glasses...

Jaz