Pars

x2 (or more...) Thanks for sharing these!

If I wanted to add a power indicator (LED), would it be best to power this from the heater supply, or from B+? I tried it with jumper clips from the heater supply and it worked fine. Kind of hard to tell when this is on or not, at least from a bit away from it.

Cardas here if you want some more foo foo parts [url=http://www.diycable.com/main/default.php?cPath=26_44_49]DIYCable.com : Intro

Sounds good Doug. Did you flip the heater rectifiers so they are all lined up the same way (eliminates any chance of tabs shorting to one another)? Post a pick of the board layout if you want any other comments.

^ Probably.

^ I would find that unusual, and think more of surges or overvoltage, particularly if all died of electrical problems.

Remind me to never loan you any gear

Surprised there is much if any difference in ride quality as I thought these were basically the same vehicle/chassis???

Power amp, tried to start on fire

It lives! Fired it up (not literally) last night, and things seem good. Takes around 4 hours to adjust bias and make sure it is stable, so will do that this week sometime. I guess the charred portion will just stay like it is as there is no plus to removing the board to clean it up as best I can, but lots of negatives as in 8 MOSFETs I could blow up...

I didn't get mine from these guys, but you could try them. Also, I see the DA models all over amazon; just need to weed out the plastic LX ones. Jewelry Tools - SEP Jewelry Tools of Chicago, Inc. Also, be aware the the higher power ones (like the DA10s I have, 3.5X) have a pretty low focal length (~4") which makes soldering, etc. a bit challenging. I've meant to get another lower powered lens plate for mine, but just haven't gotten around to it yet

He had posted some HF-worthy short post (KRmathis-like), to which I replied that he might want to read the welcome PM. I never saw what he posted in reply, but assume he must have posted something? Pity

I'm not Miguel, but have used these for a few years now. You can get them from Amazon, etc. They apparently have a plastic lens version out now for less money (LX models), but I would go with the glass lens DA models. Note that you can get additional lens plates for different magnifications, and they are easy and quick to change out. The product is by Donegal and is called an Optivisor.

I'd read your welcome PM if I were you...

Had a chance to do some more critical listening with my K601s to this the other night. Bias scheme is the new transistor bias. I decreased the CCS to 65 ohms; measured drop is 0.94V, so 14.5mA. I like this biasing the best of all that I have tried; thought the sound was quite natural, drove the phones well. Possibly a touch soft in the bass compared to my dynalo, still sounds slightly darker also, but really pretty close overall. A keeper.

Audiolab, design by John Westlake. I'd like to hear these. Sabre32 DACs, really reasonable price. Audiolab 8200CD and 8200CDQ CD Players - eCoustics.com A forum that John has been posting on as of late: At last...................... - Page 29 - pink fish media

Thanks guys. Fortunately, the damage is in the APC section (some sort of protection circuit that worked real nice, as you can see ). The two 8-pin DIP sockets you can see were populated by a couple of chips that split in half... been quite awhile since I have seen that. That portion is disabled now, with only the actual output circuitry still connected. The output FETs for these are unobtainable, and must be very closely matched. It appears they are OK, but I'll find out presently. I don't have the schematic, so am depending upon a couple of ex-Counterpoint service people on diya to guide me right now. Feels funny flying blind.

Seems like a lot of the things where I work only work with IE. IT dept. has their heads up Redmond's ass so far... inextractable. This made me laugh: Executive: Microsoft a dying consumer brand | Chicago Breaking Business

Variac (thanks for the rec Nate!). Variable AC Output Transformer MAX.20A (Metered Variac) - eBay (item 120631655275 end time Nov-07-10 14:34:08 PST) Now I just need to work up the nerve to use it on the arc welder power amp I am trying to fix for my brother. The one that was trying to start his house on fire

Another point that they touch on is if you are replacing a lossy cap with a good cap plus a series resistance of 0.8 ohms (their example) to compensate, why bother? I guess you would have to try it, or better if someone was able to analyze the FR, phase etc. changes that you brought about with your tweaks. And of course, listening.

^^ I recommend this post...

Late, but congrats, Mike!

Implemented the new bias scheme and ran some tests yesterday. I used some BC556C's that I had on hand, as well as some green LEDs which measured ~1.82Vdc. Voltage at the emitter is ~2.5Vdc. I was finding that the left channel was very sensitive to the particular LED in place, and not sure why? The first one that was in was showing a much higher threshold level in RMAA than the right channel. I tried swapping the tubes L-R, but no change. Changing out that LED resulted in the channels being much more closely matched. THD is still slightly higher than with the previous bias scheme (Blue LEDs) as well as most of the previous schemes not involving higher CCS current. I haven't tried listening to it yet. EDIT: one question: why would you not want to jumper the transformers to the anode instead of ground? Seems like this would be similar to the original instructions using LED bias? EDIT2: I did not do the extra credit of the cap

Happy Birthday Marc !!!

Not sure if any of this would be of interest to you Kevin, just did a search on Craigslist... HP3582A Audio spec an., HP8165A signal source, Hitachi V-423 o-scope Also, are Philips scopes any good? http://chicago.craigslist.org/wcl/ele/2008654797.html