I just sure dont want it to cook my pre amp, I have from mouser AD823ANZ, 3 of them. There is a small divot mark on one end, that end goes towards the relay, and small U shaped cut out on the mount it plugs into right? If there is a possibility it damaging components I will just put a new one. If it just wont work right if damaged, but no harm to preamp circuit, I'm game to try it.
Possible the old one could damage something? Now that I have the signal wires back on I could have music through it in a few!
Russellc
Possible the old one could damage something? Now that I have the signal wires back on I could have music through it in a few!
Russellc
No hum, very quiet at speaker. nutz only getting sound one speaker. Maybe mis wire at volume pot. both sides still bias at .93ish, offset low. Did spot a miss wire, but shouldnt of caused this, on of the inputs had line G mixed with In. Fixed that fired it back up. Now it hums and there is no sound from either channel. checking bias, as normal. Offset....1.5V. Yes 1.5 volt.
Swapping hot for cold signal side can mute a channel. Offset is another domain, DC. Not directly related unless something else went wrong. Like a Mosfet shorted on bad insulation again as you moved the assembly. Check that you still got correct rail voltages, and that the output relay system still works as fixed. Same for the input relays selector board. Check the rest of your wiring and try the offset procedure again.
I think this thing is haunted. Powered down, waited to drain and pulled AD823. That one did not fit well in the socket like the first one.
sort of rocked back and forth if you pressed on it. Without AD823, I was able to get to 0 or there abouts, powered down, drained and installed new Ad823 which fit tight like the first one. Offset back to normal, I probably still dont have both channels.
sort of rocked back and forth if you pressed on it. Without AD823, I was able to get to 0 or there abouts, powered down, drained and installed new Ad823 which fit tight like the first one. Offset back to normal, I probably still dont have both channels.
Seems to have worked, that explains the dropped channel. let it cook a minute or two to see if it acts up again. Hopefully the bad fitting AD823 was the cause. It just didnt seat firmly. Pressing on it, it sort of rocked from one side to the other. This one pressed in firm, no rock. Yet.
Russellc
It has run for two solid nights, offset typically .5, a little more or a little less. I'm calling it good. All the smoke stayed inside this time, except one BC550 and it's zener buddy next door. I am pretty sure it was occasioned on first fire up. I saw a tiny spark on one end of a fuse holder in power supply. Fuse popped in that location, light bar next door went dead. That is when I figured (with Salas"s help) the BC550 and zener were toasted. Once they were gone, offset adjustment was for naught, turning them had no effect, offset just cruised up and down never settling.
When I checked continuity on the mosfets, trouble, several buzzed. What I learned is the tightness required isnt as much as I thought, and over tightening compresses everything so much contact is made. Loosening them a touch solved the continuity issue. It has played wonderfully since.
Thanks Salas not only for the design and efforts, but for walking me through this build when I was having trouble! And, thanks to Teabag, who constantly measures these parts, tracks them down, puts kits together, mails them out etc, thank you for your efforts as well.
My power switch has not arrived yet, I "borrowed" the one from this for my Iron Preamp when I was building it, should be here in a day or two.
Russellc
When I checked continuity on the mosfets, trouble, several buzzed. What I learned is the tightness required isnt as much as I thought, and over tightening compresses everything so much contact is made. Loosening them a touch solved the continuity issue. It has played wonderfully since.
Thanks Salas not only for the design and efforts, but for walking me through this build when I was having trouble! And, thanks to Teabag, who constantly measures these parts, tracks them down, puts kits together, mails them out etc, thank you for your efforts as well.
My power switch has not arrived yet, I "borrowed" the one from this for my Iron Preamp when I was building it, should be here in a day or two.
Russellc
Sounding really good. Going to keep things like this awhile and get used to it. Changing phonopre from Pearl 2 to Sala's kit as wel las changing the Ironpre for the DCG3 made changes. Right now, ultra folded phono pre to DCG3, to DIY Pass AlephJ, to Tekton Enzo. Initailly had it hooked to Econowaves with phone feeding it. That worked well, very efficient, 15 inch JBL 2235H in 5 cu ft and B&C 250 CD on wave guide. Bass on Ja Wobble "Usual Suspect" shook the house.
Russellc
Russellc
In the original older pcb version the output relay when not energized just cuts the signal output open. In the current version it shorts its moving contact to ground. You were probably "measuring" the DMM's self noise in DC mV scale across an open circuit if with the former pcb version.
*The current board has a tiny V1.03 printed on its right front corner to discriminate.
Russellc, glad you have everything working. I am interested to know how the DCG3 differs in sound from the Iron Pre. I've never heard that one.
I think you will like the USFPS (or whatever it's called). A buddy borrowed mine and liked it better than both his CH Precision and CAT stages.
I think you will like the USFPS (or whatever it's called). A buddy borrowed mine and liked it better than both his CH Precision and CAT stages.
Which one have you not heard? The Iron pre? Its very nice. Im leaving all as is for a minute, made two changes ( this pre and the phono ) and that's tricky enough. After a good period, When I am refamiliarized with familiar recordings through this setup, I will plug the Pearl 2 in and listen for a while to familiarize. Once done and switched back, trade Iron pre back in, familiarize then put DCG3 and USFP back in. Phono pres vary, but the comparison that interests me is what you ask about, DCG3 vs Iron Pre. One thing for sure, neither one is a stinker obviously. It will likely be a system dependent or taste dependent difference.
I believe at least one member here, pfarrell has both pieces as well, and had them finished longer than I. Maybe he will pop in and tell his experience with this comparison. Until now, My Iron pre has been impressive. It is in my opinion, the all around best for me and my room, equipment and personal preferences of the DIYstore choices. ( I also really like and have the B-1 buffer preamp, BA 2018 linestage and the BA3 as preamp)
The board is especially nice that on one end, it has the pads for relays, so it sort of has the utility of the I-Select built in. Also on the board are two very nice shunt power supplies, making it a compact single board. All that needs added is a transformer for the preamp, volume pot, RCA jacks, selector switch, on/off switch, fuse holder and power inlet. It is extremely pleasant to listen to, relaxed. Plenty of gain (6 dB or 12 dB).
So far the DCG3 has been rock solid. It seems transparent with impact and loads of bass. No doubt it will be a contender.
Russellc
I love Iron Pre—it's an excellent match with F5 in my taste testing. Our daily beasts are M2X/Norwood monoblocks, and DCG3 is a better matchup there for us—maybe M2X + Iron Pre is too much of a good thing (Iron+Iron)? Also, DCG3 is dual mono by default and that has proven to be some audible goodness here that all of us can hear (I frequently blind A/B the family with various projects to factcheck my builder-bias). I was also able to pull off a Muses volume with Apple remote in my DCG3 build...and that too gets points with the family. One must build all the amps one can IMO! Lots to experience and learn (just ask the 8 guitar amps I have sitting around! Good company with the host of Pass related and Salas projects).
Congrats Russellc! It was quite an adventure.
Congrats Russellc! It was quite an adventure.
One of the very inexpensive pieces (Qa and Za) were cooked when I powered up with some continuity between mosfet tab and heat sink. They were fine, but when I "snugged" them tight, contact was made. No smoke, just a tiny point of spark on one end of fuse holder on PS. Light bar associated with it went dead.
Restoring fuse brought the light bar back, but Qa and Za were toast, and caused all that fuss. Should have checked for continuity again after the snugging.
Live and learn. Hey I'm like wolfgang puck! Live, learn build...
Russellc
Restoring fuse brought the light bar back, but Qa and Za were toast, and caused all that fuss. Should have checked for continuity again after the snugging.
Live and learn. Hey I'm like wolfgang puck! Live, learn build...
Russellc