Pars

Happy Birthday!

Congrats to the Hawks for winning, and to Tampa for a great playoff run and fight in the finals!

R2 in schematic?

Happy Birthday!

I believe the 20 ohm resistors are paired to get a 10 ohm resistance.

How big are these things? I only ask because I did a half sigma22 layout (only 1 pair of output FETs) and used it in a CD player to power the I/V stage. Board on the right. I didn't bother heatsinking the output FETs on this because of the low current draw.

Yes, thanks for resurrecting this thread Dusty! Thanks to all who have served and sacrificed!

I don't know if they ever asked if they could use it or not. Maybe Jude felt that since the real CanJams were head-fi supported events, that he automatically owned the name... still funny that the last one (CanJam Chicago 2010) was run entirely by HeadCasers

Input grounded? Or do you have a volume pot installed and turned down all the way? If not, ground the inputs.

Yeah, didn't the Florida crew coin that name when it was still actually CanJam, as in user driven? I think HF should be paying them royalties for its (mis)use

I/O connectors are Molex KK 0.100" such as Mouser 538-22-10-2031. The PSU connectors are Molex SPOX 0.200" such as Mouser 538-10-32-1031. And your sockets...

Happy Birthday Raffy! Don't ride too much

Oh shit, I forgot to use the C37 lacquer... I'm truly fucked now

Pics (iphone) Input jacks with switch for RCA/XLR Amp boards and pot Sigma22 psu and transformer, set for +/- 16.2Vdc (gain resistors still socketed). L channel amp board. Still have the bias resistors (R38/39) socketed, 301R in there currently, resulting in 18-19mA current in the output stage. Also using 2SJ74/2SK170 JFET input. I also didn't populate the 4.7uf Wima caps as I'm not sure there is any point to them being there. Sounds very good, still evaluating compared to my other Dynalo. Dead quiet. I have only tried SE inputs so far, and don't notice any difference between the switch up (- inputs into the amp tied to ground), or down (- inputs wired to XLR but floating). Gain seems sufficient now that I have the input wiring issues sorted. It will be awhile before I case this, so I just mounted it to some scrap veneered plywood I grabbed from home depot for a buck, stained and polyed. EDIT: small pieces of clear tubing used as board standoffs, in case anyone was going to chastise me for mounting them directly to the wood

Happy Birthday!

Found that there is nothing wrong with the pot. When I saw that the measurements of each section at a particular rotation weren't really far off, it didn't jive with what I was hearing. I found some connection issues; 2 crushed pins on the L out from the pot, and 2 broken wires on the input cable from the L jacks (that were still making some connection). Once fixed, it sounds much better now. This is the first time working with the radio shack rainbow wire (a favorite of rickcr42 from HF, RIP), and I can't say so far that I am a fan, other than it being ribbon and solid core. The insulation absolutely sucks as it melts if a soldering iron looks cross-eyed at it. So, in the words of the immortal Emily Litella, "Nevermind, bitch".

It looks like this other than mine has the flatted shaft:

Alps RK27 10K motorized

Thanks GT and Kevin. I could always pull the opamps for what GT is saying. I could also just measure it on RMAA (I think my Audiophile 24/96 will do balanced?). Not only for L/R channel balance, but what effect do pot imbalances have regarding +/- channels? I would certainly think some as well, but not sure how that manifests itself. I wonder if Birgir has any of the 4CP-601 TKD pots he'd be willing to part with? Also, I recall the thing you can do to a 2 channel pot to use it for 4-channel, but it seems that only typically works on certain types of inputs? EDIT: No on my m-audio box doing balanced

Listened to my multiamp a bit yesterday and this morning. I seem to have a slight channel imbalance, using SE inputs with the L/R- inputs tied to ground. Swapping the input and output cabling around, it seems to be the pot that is causing the problem. The R channel is slightly louder than the left. Measuring the pot, this is what I get at the approximate rotation I was using for listening: L+ L- R+ R- pot total 9.884 9.707 9.721 9.811 3/4 rot 5.714 5.768 5.643 5.776 % 57.81% 59.42% 58.05% 58.87% This doesn't seem off that much (57.81% vs. 58.05%). All figures in K ohms. Output taken to ground. Any thoughts? It seems worse at lower volumes and gets a bit better at higher volumes, though going much beyond 3/4 rotation gets louder than I care to listen to. I've checked resistances some on the cabling from input through the pot, and I didn't find any bad solder joints or anything yet. Any thoughts?

Thanks all! Had a very nice birthday, low key, but nice.

Machine pin sockets like Mill-Max, Augat, etc. hold the IC pins much more securely than the type you are using. When I was a tech back in the '80s I spent a lot of time reseating chips in the kind of sockets you are using; once reseated, equipment back in business (for another day or so). Sockets are so cheap you might as well use good ones. Kevin commented on this in post 95, parts list using 571-1825093-3. vs.

You really should use better sockets for the opamps and I presume the THAT340 that one you have there (those are junk). Mill-Max or equivalent machine pin sockets 575-193308 for the 8 pin 575-193314 for the 14 pin are good ones.

RIP BB King

Happy Birthday!