Switching the dual voltage PT taps

robert · Post by **robert** » Thu Oct 26, 2006 12:02 pm

I believe that epoxy fumes are toxic and will drive one insane, time after time

Maybe George knows that

Robert

mightymike · Post by **mightymike** » Thu Oct 26, 2006 1:53 pm

Thanks for sharing this George.
I put a pot on my switch instead of the resistor.
Works like a charm.

Here some pics

http://kymer1.home.comcast.net/images/dualtap.jpg
http://kymer1.home.comcast.net/images/dualtapswitch.jpg
http://kymer1.home.comcast.net/images/m ... p12000.jpg

Now all I need is 3 labels (435v, off, and 480v) to stick on the front.

antosimoni · Post by **antosimoni** » Thu Nov 02, 2006 8:05 am

sorry if I come in again but can some1 please give me confirmations about the A - B - C relations I've put on this 2 pictures??? its important, thanks a lot

BashCoder · Post by **BashCoder** » Thu Nov 02, 2006 9:08 am

wdelaney72 wrote:But George, according to the Caswell, Bray, and Assclown business model, you are supposed to keep this a big secret.

No doubt! You know what's really cool about this? George thinks bigger. He's not trying to build (and protect) a $40/hr bench services business. I think he's building something a lot bigger, broader and more substantial. He's not trying to build a brand or mystique around one particular mod. He's creating an environment within which regular folks are building some pretty amazing amps, and at great prices too. When George does research and product development, thousands of people benefit - not just the chosen few. And the amazing talented folks here reciprocate, and it gets even cooler. So when I buy this stuff, I buy from him, and so do a lot of you.

To me, it once again proves we're hanging in the right place, with the right guy!

mightymike · Post by **mightymike** » Thu Nov 02, 2006 10:25 am

antosimoni wrote:sorry if I come in again but can some1 please give me confirmations about the A - B - C relations I've put on this 2 pictures??? its important, thanks a lot

Yes you have it right except for A needs to be on the other side of that 27k resistor. (the side where the wire the white bias wire is connnected to the 27k)

wdelaney72 · Post by **wdelaney72** » Thu Nov 02, 2006 10:31 am

How often does the resistor value swing away from 22K? Will it be different with every set of tubes?

If that's the case, I'm liking the 25K pot.

chris · Post by **chris** » Thu Nov 02, 2006 10:52 am

awesome info, I was wondering about the variance between tubes too, the pot seems like a good idea to me, but maybe its not necessary.

antosimoni · Post by **antosimoni** » Thu Nov 02, 2006 10:58 am

thanx MIGHTYMIKE !!!

mightymike · Post by **mightymike** » Thu Nov 02, 2006 11:14 am

wdelaney72 wrote:How often does the resistor value swing away from 22K? Will it be different with every set of tubes?

If that's the case, I'm liking the 25K pot.

Bingo..that's what I was thinking the benifit of it would be. I figure if sell this amp, the new owner only needs to know that there are 2 bias pots one for each range, and this way he doesn't have to learn how to change the resistor if he changes to output tubes that are different enough that they would warrant a bias range resistor change in a stock amp.

Or maybe it tracks with all tubes once you have the switched dual tap range resister set? Maybe someone with George's dual tap that has tried a bunch of different tubes can answer this.

Also with a pot you really dial it in exactly to where you want down to the .1mA.

thanx MIGHTYMIKE !!!

No Problem....Just giving back..
Thanks to George..

Post by **VelvetGeorge** » Thu Nov 02, 2006 11:42 am

Antonio, that is correct. Just move the "A" to the other side of the resistor as Mightymike pointed out.

VG

mightymike · Post by **mightymike** » Thu Nov 02, 2006 11:48 am

If you're using a 2nd pot, you could add a turret right next to the 27k turrent where the white bias wire comes in. In the unused perf hole between that tuuret and "B". and mount the pot or resistor across there, and put the white wire to the added turret.

It would look nicer than the pot on the switch.

antosimoni · Post by **antosimoni** » Thu Nov 02, 2006 12:59 pm

thanks Mike and thanks George... just another question : I dont have to add the resistor where I've putted the "A" right?? its already there in my amp...

mightymike · Post by **mightymike** » Thu Nov 02, 2006 1:42 pm

You already have a 27k there if that what you mean. That's the resistor already on the board with the white bias wire is going to it. When I was saying you could put a resistor or pot on the board, I meant instead of putting in on the switch like in the diagram. either way is fine though.

Post by **VelvetGeorge** » Thu Nov 02, 2006 1:44 pm

Thanks for the help with this MIke.

Your tubes arrived today, I'll get them matched up over the weekend.

VG

rockstah · Post by **rockstah** » Thu Nov 02, 2006 1:46 pm

i say put the second bias pot on the power board!