August 25, 201411 yr I only gave him the attenuator boards. Not the multiamp. I had to do a lot of surgery on my multiamp boards to get them to match the current design.
August 25, 201411 yr I got the multi amp boards from Birgir, marked multi amp rev 1.0. After looking at my pcbs, other than a lot of differing parts values on the silkscreen compared to the schematic, I think it's basically the production board design except there's a missing 10k resistor by the servo, there are spots for the 4.7uf decoupling caps, and r21/r25 are combined into a single 20k resistor. I can't really tell what the 10k is connected to from your pic, could you tell me? Edit: Nevermind, found it. It's connected in between r21 and r25. May have to offboard those resistors. Edited August 25, 201411 yr by mypasswordis
August 28, 201411 yr Just (hopefully) bought all the parts needed to build the KGITSOCH minus the LSJ74s which go for a mind-numbing ~$6 a pop in sets of 8 at diyaudio, and the case which I probably won't get for a long time. Any of you buy the LSJ74s and have good success with matching?
August 29, 201411 yr Okay well I'll just get a set of eight and the closest four of the eight will be the ones I use. Audio stuff is making my wallet take too massive of a beating. Probably gonna have to order the THAT340 for the Multi Amp boards unless the other four are relatively close.
August 29, 201411 yr Author I'm sure somebody has matched J74's for sale. Has to be... Edited August 29, 201411 yr by spritzer
August 29, 201411 yr I have a bunch of matched jfets I was planning to list, but life is too crazy now... I drug them out of a pile and moved them to yet another pile and am not sure where they are, or I would check. Hit me up week after next and I should be able to have time to locate them.
August 29, 201411 yr I have a bunch of matched jfets I was planning to list, but life is too crazy now... I drug them out of a pile and moved them to yet another pile and am not sure where they are, or I would check. Hit me up week after next and I should be able to have time to locate them. Thanks, will do!
August 30, 201411 yr Hey Spritzer, what does your FET and transistor test/matching circuit look like? Am I fine just going off AMB's examples - Device matching? There are so many different test circuit suggestions >< Gonna try to get a matched FET quad from FETaudio too
August 30, 201411 yr not bad for a senior citizen http://gilmore.chem.northwestern.edu/dynalobalss.jpg I don't even do any metal work by hand anymore, even for the bottom panel which is just 8 holes, I do it in the NC mill and unlike Mikhail the holes end up in the right place the first time.
August 30, 201411 yr Author Not bad old man!!! I guess this means I have to build mine? I sure could use the NC mill having done 7 front panels by hand today... Hey Spritzer, what does your FET and transistor test/matching circuit look like? Am I fine just going off AMB's examples - Device matching? There are so many different test circuit suggestions >< Gonna try to get a matched FET quad from FETaudio too The B22 stuff will do just fine but you can build this amp without any matching and it will work just fine.
August 31, 201411 yr The B22 stuff will do just fine but you can build this amp without any matching and it will work just fine. Thanks boss! You got a drill press for all your metal work stuff?
August 31, 201411 yr Author You can't do most of this stuff without a drill press but I do need a new one with more reach. This one is older than I am...
September 1, 201411 yr What are my options if I want populated and tested amp + psu boards of this amp? My soldering skill is 0 but I want this amp. Any helps are appreciated. Thanks.
September 1, 201411 yr parts list in progress so with the pot its about $300 in parts. need mounting screws, standoff's etc... item # $ 240 ohm 4 0.2 0.8 680 ohm 8 0.2 1.6 402 ohm 12 0.2 2.4 2.74k ohm 8 0.2 1.6 3.01k ohm 8 0.2 1.6 24.9k 4 0.2 0.8 5k 4 0.2 0.8 10k 6 0.2 1.2 49.9k 8 0.2 1.6 100k 4 0.2 0.8 20 ohm 32 0.2 6.4 14 pin ic socket 0.97 1uf 4 0 5pf 4 0 100uf 8 0 4.7uf 8 2.37 18.96 op07 4 1.56 6.24 that340 2 6.4 12.8 mpsw56 22 0.44 9.68 mpsw06 22 0.51 11.22 led 4 0 10k pot 6 0 haa15-.8-ag 63.63 boards 2 10 20 galaxy 288 69 rk27 quad neutrik chassis female 5 4.29 21.45 253.55 Edited September 1, 201411 yr by kevin gilmore
September 2, 201411 yr This is what I put together for the amp board only....any errors or suggested changes let me know:http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=33c64fee31 This has R38/39 reduced to 200ohm for 20V rails so I can jack my KSA5 power supply into it. Also could not find reel or tape for the mpsw06 so went with straight legs. Typically I prefer the prebent legs. Tempted to put it in the galaxy chassis like you did with that haa15.... parts list in progress so with the pot its about $300 in parts. need mounting screws, standoff's etc...item # $ 240 ohm 4 0.2 0.8 680 ohm 8 0.2 1.6 402 ohm 12 0.2 2.4 2.74k ohm 8 0.2 1.6 3.01k ohm 8 0.2 1.6 24.9k 4 0.2 0.8 5k 4 0.2 0.8 10k 6 0.2 1.2 49.9k 8 0.2 1.6 100k 4 0.2 0.8 20 ohm 32 0.2 6.4 14 pin ic socket 0.97 1uf 4 0 5pf 4 0 100uf 8 0 4.7uf 8 2.37 18.96 op07 4 1.56 6.24 that340 2 6.4 12.8 mpsw56 22 0.44 9.68 mpsw06 22 0.51 11.22 led 4 0 10k pot 6 0 haa15-.8-ag 63.63 boards 2 10 20 galaxy 288 69 rk27 quad neutrik chassis female 5 4.29 21.45 253.55 Edited September 2, 201411 yr by GrindingThud
September 2, 201411 yr This is what I put together for the amp board only....any errors or suggested changes let me know:http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=33c64fee31 This has R38/39 reduced to 200ohm for 20V rails so I can jack my KSA5 power supply into it. Also could not find reel or tape for the mpsw06 so went with straight legs. Typically I prefer the prebent legs. Tempted to put it in the galaxy chassis like you did with that haa15.... FWIW: Kevin's BOM lists 4x OP07 a single opamp, and your Mouser BOM lists 2x OP275GPZ, dual opamps with a different pinout. Edited September 2, 201411 yr by Laowei
September 2, 201411 yr Doh, that was supposed to be OP27, not 275. Good catch! Also, I did the BOM per board, so quantities are half. FWIW: Kevin's BOM lists 4x OP07 a single opamp, and your Mouser BOM lists 2x OP275GPZ, dual opamps with a different pinout. Edited September 2, 201411 yr by GrindingThud
September 2, 201411 yr Doh, that was supposed to be OP27, not 275. Good catch! Also, I did the BOM per board, so quantities are half. Did the same on my KGST BOM too. Caught it before I ordered. Edited September 2, 201411 yr by Laowei
September 2, 201411 yr the lead spacing on the board for the .1uf cap is 3.5mm but the .1inch caps do fit. the 5pf caps are 5mm lead spacing by the way, I have a new name for the thing... PureBipolar (tm&c) would apply to the ss dynahi too. Edited September 3, 201411 yr by kevin gilmore
September 3, 201411 yr Gotta love a little Bipolar now and then.... Speaking of bipolar, how do you like that haa15 PSU? Is it quiet? Was thinking of using that with maybe a little off board capacitance if it needed it. The Krell went overboard with capacitance....this design seems much leaner. Thanks for clarifying the spacings by the way, I have a new name for the thing... PureBipolar (tm&c) would apply to the ss dynahi too.
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