luvdunhill

agreed, I think that's one of the reasons they seem to mysteriously fail open. The incorrect marking is even more disconcerting. Props to PcX for taking care of me though and not being total assholes about it (other than asking what I measured them with, and it seems that the word Keithley was sufficient). That sort of makes me think that this has happened before... then I ran into that post via Google...

Has anyone else had problems with PRP mismarking resistors? I found some, and then ran across this post: http://www.audiocircle.com/index.php?topic=67078.0 PcX is providing replacements, so I'm on hold for a bit.

no, good matches are very hard to get between the devices 2SA1145/2SC2705. I in fact have nearly perfect matches, the front end, and even the MOSFETs. In general, low hfe devices are more consistant. For example, try matching the 2SA1349/2SC3381, it's very hard. That's why I used single devices... and then matched a crap load of them. This is neither here or there though, the circuit shouldn't really care that much about this anyways...

Making some orgeat

I did graduate work at Columbia and rather enjoyed it. It was in Computer Science though.

I constructed both CCSes on a breadboard and chose a resistance that resulted in 2mA current draw. I'll use the same devices on the actual board. I'll do this for the other CCSes as well. Looks like I'm lacking one resistance (figures). I'm going to have to take stock of what I have and make one order to shore things up.

well, for what it's worth (I just measured this), with a Vf of 1.838V I get 595 ohms for the top (R21) and 560 ohms for the bottom (R22) to draw 2.000mA through the front end. Hfe of both polarity (yeah I know obsessive) is 136 and the Mouser part for the LEDs are 859-LTL-4213. So, perhaps turn it up a bit.

Also, Vbe of the transistors in the DynaFET are .1V or so higher than those in the other Dyna- designs, IIRC. Yes, that's the man!

500 ohms assumes a 1.6V LED, which results in 2mA for each half of the front end (1mA per FET). I plan on choosing LEDs an adjusting this value to result in the final 2mA. Seems easier to me. I don't have any EAGLE files. I'd recommend PMing Dan C and see what he can do to help.

what is R55 again? I'm getting closer to getting a new board stuffed. If you don't mind, what equivalent resistance do you have across R22 || TR2 and R21 || TR1? I'd like to put a fixed resistor there and was thinking 560 ohms (assuming that the design point was at the center of the pot).

Still cannot use this new website, none of these posts showed up new for me. Can you drive more current through the output stage? I'd guess this to be the problem. I'll be caught up with you in a few days and we can compare notes. Stuffing basic stuff tonite hopefully.

It's not hard really. High PSRR.

This.

you can feel it though what's a few extra watts though?

Nice! The lower gain just needs more compensation. I tested it down to 3 I believe. I'd definitely try both feedback points, it's worth it.

All those Kirsch drinks were nice. The layering with the sweet vermouth and Kirsch was especially nice.

That would be "The Rose"

I was just about to recommend this one. That recipe exactly too.

Margarita Equal parts

2 oz dry vermouth 1 oz kirschwasser 1 tsp raspberry syrup Shake and strain into a cocktail glass and garnish with a cherry.

Following Jim's lead.. Blackthorn Cocktail 2 oz gin 0.75 oz Dubonnet Rouge (0.5 oz Carpano) 0.75 oz kirschwasser Stir.

Yet another link that doesn't work with Tapatalk around here (the first one) (grumbles)

That's about right. Totally hit the spot tonite. Nice to be back in the sling of things

Thanks kind sir!

The Straits Sling 2 oz gin 0.5 oz kirschwasser 0.5 oz Benedictine Juice of 1/2 lemon 1/4 tsp orange bitters 1/4 tsp Angostura bitters Soda water Shake everyone on ice (except the soda) and strain into a sour glass. Add soda. Add fruit.