ImPasse Preamplifier

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#123
I'll need a board. It would be churlish of me not to order one, after all, SY started this project to help me drive my F4's Would like the DN2540N5's and resistors installed if you are willing. I am in no great hurry, so if there is another board run in a month I can wait for that...Actually you have those great kits at your site.. why not an Impasse kit o parts..

Mark
 
#130
RKH said:


PPS: What's the pin spacing on the board for C3 & C4?
Click to expand...

I have the Vishay MKP1840 0.47u/630V in there now, but you can also fit Wima MKP 0.47/400 -- two sets of holes.

I used the WIMA MKP 0.1/400 for C2 and C5.

Almost all the parts can be had from Mouser (including the DMOS FETs and the NE2H lamps). The tube sockets I have on hand from Parts Express (or from Barry Electronics which used to be on Broadway 40 years ago!).
 
#131
Here's the board -- with the transformer part snipped off (these will be mounted on the rear of the PAS cabinet -- it fits perfectly inside the PAS! It's mounted on 1/4 inch nylon standoffs below the chasis and clears both top and bottom. The Dyna transformer isn't going to be up to the job so will be changed-out. I think this is the ultimate POOGE:

An externally hosted image should be here but it was not working when we last tested it.
 
#136
Well, this is not your virgin Impasse -- the tone controls and balance are disabled on my Dyna PAS -- I am going to use the heater connections from the original transformer to supply the electronics shown here, and a small transformer whose center tap i can lift to the B+ for the 6SN7 and 6922. On the PAS there's a "filter" switch which I can use to fire the Silonex LDR's. As I already have a couple of ALPS pots I don't see any need of an LDR attenuator at present:

An externally hosted image should be here but it was not working when we last tested it.
 
#138
I still haven't fired it up as I don't have a 6.3VAC filament transformer with a center tap at the moment...when I can make sure that they work without a hitch I'll send them out.

I put the boards on the bottom of this page:

http://www.tech-diy.com/Store/CloneKits.htm

The prices are adjusted to net out the paypal fees and no allowance for anything above the USPS shipping charges.

The ceramic sockets from Parts Express work fine, you just have to scootch the octal pins a tad to get them all to fit.
 
#139
Hi Jack,

Since you filter out the webmail email, I will post it here.
Looks like the button does work. I ordered the

Impasse PCB plus soldered-in DMOS DN2540N5 and resistors for 8mA -- US
which is 16.30, plus shipping and PP fee 6.25, total is 22.55.

So, I think I still owe you $10 that you just refunded me.

Thanks!!
 
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