Pars

No I don’t, at least that I want to get rid of. Also, I’m interested in Kevin’s latest large cap version, which checks most of the boxes I was looking for. The SiC rectifiers used on that are Schottky... The larger diameter caps would allow much shorter (25-30mm) caps to be used, allowing something like a 1U chassis for a Dynalo Mk2, etc. Sent from my iPhone using Tapatalk Add what? Rectifier boards? Kevin’s latest large cap GRLV? The mid-size GRLV? Sent from my iPhone using Tapatalk

Ahh, that makes it clearer. The height issue is caused by the headers I am using (the plastic breakaway strip), so I can deal with that. I'll either get some nylon screws or drill and tap the heatsink for 4-40 or M3. The TO-220 silpads I have aren't quite long enough to cover the 3 annular rings, so I cut a strip and put it there so all is covered.

Question regarding the mini heatsinks in the BOM, Aavid 581002B02500G. I didn't realize these were tapped for 6-32, rather than something more rational, like 4-40. The screw head for a 6-32 contacts the regulator chip, which doesn't seem like a good idea. The TO220 mounting kits and parts I have are all sized for 4-40, including the various insulators I have. I noticed in Kerry's build that he used an insulator that covers the screw head... can't tell for sure what it is exactly. Additionally, Amb's o78/o79 are a bit taller than normal TO220s and with the Molex or 3M headers I used, sit a bit taller than the mounting hole. They also sit out from the heatsink at the bottom. In the image on Amb's site, it looks like he bent the pins slightly (but doesn't mention it). I guess the screw issue is the largest one. Any thoughts/suggestions? Not enough room between the fins for a nut.

Yep to both you and WInk, though my impressions of the Stanton vs. the Shure were reversed. I wish I wouldn't have tossed the Shure (maybe I didn't? Hmm, have to look). I always liked that cart on a Thorens (TD160... never tried it on the TD320 I have now). Back in the early '80s, when my wife and I had first married and moved to the Dallas area, I had brought my beloved (at the time) Infinity Monitors (Walsh tweeter) with me, but nothing to run them with. I went out and bought a Hafler amp/preamp (big stuff back then ). After going thru a crap Sony Linear turntable that liked to drag the cart across the grooves periodically, I bought the Thorens 320 (online out of NY). I bought a HO MC cart that I liked a lot, think it was an Apogee? Searching I find no such cart or info about it. At any rate, it was a good sounding cart, even thru the crap phono stages back then.

Cool. Just as a note, you might consider going a bit wider to allow a 0.25” or so gap along each side of the board. (I didn’t check or note the dimensions on your drawing) This would help with airflow/cooling (I think). There is an AC trace down one side of the board so you certainly do not want to use the case slots for the PCB. Sent from my iPhone using Tapatalk

There is a clearer drawing of the case layout on context engineering’s site here: contextengineering.com/desktop_enclosures.html Sent from my iPhone using Tapatalk

I could be interested in a 2CP2500 or 2511 in 10K as well.

Here is the latest CFP gerber file with the servo mod, along with the schematic: cfp2hmt.zip cfa2cmirror.pdf

The screws I was referring to are those that put the case together (front panel, rear panel, top and bottom panels. Sent from my iPhone using Tapatalk

That looks really good in terms of pricing. I liked johnwmclean’s design in terms of the lettering/symbols. My preference would be for black ano with white or natural aluminum (or laser printing). Another concern is fasteners. For the fr/rear panel mounting, are these threaded or is it possible to use a std. threaded fastener (4-40, M3, etc.)? Or do they just use self tapping screws? I would prefer something that could take a std. fastener. I also strongly prefer using stainless steel hardware. Additionally, it appears that the top/bottom panels are screwed on? This could be an advantage from the FPE profiles in that you don’t have to take the whole thing apart to take the top off, for example. Their website leaves a lot to be desired in terms of images of completed enclosures [emoji4] If it is decided to go this route, I would be interested in 3 cases. Thanks for all of your work so far on this! Sent from my iPhone using Tapatalk

Well, looks like the cool kids can still buy some sort of liquid carbon... https://www.massdrop.com/buy/massdrop-liquid-carbon-x-sdac-dac-amp?utm_source=Iterable&utm_medium=email&utm_campaign=ccu_Massdrop_Liquid_Carbon_X_SDAC_DAC%2FAmp&referer=K6U6H7&mode=guest_open&iterableCampaignId=233692&iterableTemplateId=333094

Could be interested. Would the anodizing be done after machining?

In talking with cspirou (sp?), you may want to rethink the 3 oz. copper on the mini board. Kerry’s prototype was done using 1 oz. copper and he didn’t think it needed heavier. The 3 oz. boards aren’t much fun to solder on, particularly when you consider that the majority of the pins on the regulators go to ground. Just sayin’ Sent from my iPhone using Tapatalk

Dynamic Sent from my iPhone using Tapatalk

Don’t forget CFP2. Also, I would like a GRLV version that supports multiple outputs, SiC rectifier diodes, and larger (30mm min, 35mm great) caps. I don’t think this has been laid out yet (close). Props for supporting both Phoenix 5.08mm and Molex KK 2.54mm connectors on the outputs. [emoji4] Sent from my iPhone using Tapatalk

I need to get one of those myself (had run across them before but never pulled the trigger). I have the Molex hand crimpers and they leave quite a bit to be desired.

Happy Birthday Mike! Hope it is a great one!

Happy Birthday! Sent from my iPhone using Tapatalk

Ok stupid question time [emoji4] I hadn’t seen this kind of symbol used on a silkscreen before for a polarized cap (the 100uf caps): Which end is +? I’m guessing the closed end of the symbol? I suppose I could figure out which rail is which and then I’d know for sure Sent from my iPhone using Tapatalk

Yes, I understood what johnwmclean meant when he said soldering this board felt like it was sucking the life out of his soldering iron. I had no trouble with the pads under the regs, which are also connected to ground. Just the small pads. Sent from my iPhone using Tapatalk

As for cutting the output resistors in half, I guess it would double the current? Not sure if that is advisable though oftentimes more is better. I would think you would need to re-bias it however. Group buy mini board question: Noting the trouble I had getting some of the LDO pads to tin, is any special cleaning of these boards required? I only scrubbed the area with rubbing alcohol/toothbrush. Do I need to take some scotchbrite or something else to these boards before building? Sent from my iPhone using Tapatalk

Tried my hand at soldering a pair of the regs on, using a Hakko 936 with a 3.2mm chisel tip. Had a hard time getting some of the pads to tin on the neg reg, used plenty of flux. Switched to my smallest point tip and ran around the outsides of the chip (from the YouTube video). My hot air station hasn't arrived yet, nor have the Meanwells. I'll put the associated components on tomorrow night and probably use my bench supply and see what happens. Sorry for the crappy photo, but let me know what you think.

I know, bad form quoting myself Order arrived on time today. It appears to have been picked correctly, as long as everything was in the correct bin. Didn't ohm anything out (will do that when I assemble). Damn, is Mouser back on their game? It did take me about an hour to go thru everything against the packing slip.

Thanks, and yes I had found them on Mouser myself. Order was already placed at that point and I would have been concerned about the height. The Vishay cap T55D107M025C0060 has very similar specs to the Kemet, is less than half the price ($1.27 vs $3.56), is the right footprint (2917/7343) and is short at 2.8mm. I should have ordered those instead. Not sure what the reputation of that Vishay division (Polytech) is though. Sent from my iPhone using Tapatalk

Nice Kerry! Loving the SiC rectifiers. Would love a GRLV done like this (both std. LT1021 and your lower voltage version here... not sure if a single PCB could support both?), with 1) 3 output terminal blocks (2.54 and 5.08mm pitch) 2) Dispense with the 3rd bridge support 3) Support up to 35mm main caps This of course doesn't fit with your less/smaller goals above... might be great for the next GB