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Condolences Brent. RIP Alex. Sent from my iPhone using Tapatalk

Rechecking with reduced bias (13-14mA). Max device temp (no heatsinks) that I measured was 92C (R- bank, back around the AC/DC SMPS). Most are around 80-85C. Still sounds good, maybe not quite as good, but not really noticing much difference sound-wise. These temps are just an artifact of the form factor. Unlike your full-size, the output devices on these are concentrated in a 4"x2.5" area. My thru hole full size runs much cooler as well.

I just ran pretty much the same on the 2nd amp, with more or less the same results. I'm going to play around with the bias a bit and will report back, though these things normally sound the best biased as high as you can get away with (within reason; I think Kevin had commented regarding the full-size that around 20mA was the sane max).

Without the heatsinks, I am seeing the following (IR gun): ~45 minutes (no music playing) Top: 41C Transistors (hottest): 102C Bias is a bit hot at ~345-360mV = 17-18mA (this is with 402R resistors and the LiteOn LTST-C170CKT LEDs (1.56V drop). Maybe I'll toss in some 422R for the bias and recheck; that had always measured low initially (12-13mA), but I'd never run it this long in that configuration.

Yes, that is the same size I used. As I noted above, I'm not sure these run cooler with the heatsinks. I'm going to do some more testing tonight.

You didn’t consider an adapter cable instead? Sent from my iPhone using Tapatalk

Good god! Hehe... he was right! I remember a number of years ago my wife and I had gone to see the CSO perform Holst - The Planets. We were in the gallery (highest balcony = really good sound). During the 7th movement (Neptune) where the disappearing choir was singing to a fade out (in the entrance or whatever it is called for the upper balcony), two bitches in front of us just wadded their programs up. My wife and I could have fucking killed them!

Listening to nopants amp tonight (Curve - Doppleganger). Sounds awesome! iphone -> Vox w/no eq -> amp -> modded T50RPs. I'm really enjoying this tonight... Pics remind me I need to clean it as I've been abusing it in the basement for a bit. Also don't have the heatsinks installed yet. It seems the top, etc. don't get as hot... I'll have to shoot some temps with my IR gun tomorrow. I know @johnwmclean doesn't run heatsinks on his and felt it ran just as cool.

Yep. The new mini looks great.

The Lemo stuff always looked kind of long for a headphone connector on the cups, but I've never used them. Also very expensive, think I saw one that was $110 ea. Which fake China stuff have you used? I'll have to measure and see what I can get away with diameter-wise. I was also looking at SMC connectors, but they might actually be too small in diameter.

Why not? You might have to recheck the offset. If you feel this is bright, I would go with JFETs instead as I don’t think you will gain anything with the 3381s. Sent from my iPhone using Tapatalk

There are a couple in posts 814/815 from 12/10/2016 Sent from my iPhone using Tapatalk

Well, the “build quality”* looks great, what could go wrong? * otherwise known as the enclosure... Sent from my iPhone using Tapatalk

I used knobs from eBay seller AudioGD and liked them quite a bit, finding them to be nicely finished. 25mm is about as big as you can go on these; might get away with 30mm. Sent from my iPhone using Tapatalk

Thanks Nate. I ll consider those, but a bit pricey since i would also need the plugs...

Don't adjust the pots with the servo 0R jumpers in; normally this is done without. And yes, those look like good results. What does the other channel look like?

Yep, when I tried the onboard regs, I had problems getting the jumpers to bridge properly as well. They do go to ground, and anything going to ground on the 3oz boards was a problem, particularly if you were trying to use a sane tip size for the application. The tab on O23 looks a bit light on solder... looks like you used hot air and paste on most of the SMD?

I guess I might as well post this here: I have a pair of HifiMan HE4XX (Massdrop) which use the 2.5mm connectors on each headphone. These are crap, and cut out if I move my head the wrong way, etc., so I was toying with replacing them with something better. I was wondering what other connector types people use, either with experience on commercial headphones, or DIY, and how they like them. I have tried the Mr. Speakers Hirose connectors (on a pair of Aeons) and liked them, but wanted to ask around as there might be something better that I am unaware of. I have also used a Switchcraft mini-XLR 4 pin on my modded Fostex T50s, but for the HifiMan wanted to stick to separate cables to each cup as they are stock. Plus for something that is around the same diameter as the 2.5mm jacks currently in the headphone cups.

I wouldn't worry about that offset. I would adjust the trim pots a bit. The channel layout, looking at the top of the board from the front is: L- L+ R- R+ The two pots by the LEDs will adjust the overall offset for its respective channel. The other 4 pots will adjust the channel it is nearest to. If you have two meters and can watch the + and - of each channel at the same time, that would be best, as the pots will have some effect on the opposite + or -. Don't go overboard in adjusting trying to 0 everything out. As the amp heats up, the channels will drift without the servos in place. BTW, how did you do the onboard regs? Hot air station?

Those fuckers don't number their pins though...

What is the accepted std. pinout for team 5 pin? Use the current 4-pin pinout and add the gnd on pin ? Or? 1 - L+ 2 - L- 3 - R+ 4 - R- 5 - GND EDIT: Shure does it this way for the VP88 Pin 1: Shield/ground Pin 2: left channel + Pin 3: left channel - Pin 4: right channel + Pin 5: right channel -

Yes to most of it. For the LED resistors, which set the bias, I used 422 402R with LTST-C170CKT Lite-On LEDs. This gave me the 14-15mA bias. Running 402 422R with these LEDs will give you 12-13mA. You're going to try doing the onboard regs? Good luck, though the 2oz boards will make these easier than the 3oz were.

I'm using 10K pot with JFETs (Linear Systems). Batteries have noise as well, so if it were a GRLV, I'd be tempted to think it would be superior. Never tried it though. Can you fit the batteries in the case? And what would you do as far as the power switch goes?

Happy Birthday Marc! Sent from my iPhone using Tapatalk

Happy Birthday Dusty!