April 22, 20179 yr comment_762547 GRLV +14.99 -14.98V GRHV +419.98 -419.89V getting very very close Report
April 22, 20179 yr comment_762549 Woah seems you recieved the package,congrates! but looks like some of your 10m90s aren't flat on angle bracket? Edited April 22, 20179 yr by ang728 Report
April 22, 20179 yr Author comment_762552 the copper ground straps are a bit of overkill. definitely make sure all the tab transistors are flat to the heatsink Report
April 23, 20179 yr comment_762621 I got music!!! Thank you Kevin, Soren, Joe (beautiful chassis) and all that helped me!! running at 18mA. Edited April 23, 20179 yr by Whitigir Report
April 23, 20179 yr comment_762647 Thanks! And happily reporting that there is no "hum", not even a fainted bit . Excellent transformers, thanks again Joe and Ang! it had been running for 3 hours now, and temp is steady at 39 C on the chassis. Edited April 23, 20179 yr by Whitigir Report
April 24, 20179 yr comment_762729 On 4/23/2017 at 8:12 AM, joehpj said: Push'em harder! 20mA at least I just turned her to 20mA and using reissues mullar el34. She dives deeper but and finer trebles but has more distortions on deep Sub bass and some trebles at complex passages. No weird glowing plates or such...... Is GG ok with 20mA ? Gotta wait on 6ca7 and see if it helps anything... well, after reading some more, it appears the Mullar just....sucks....lol Edited April 24, 20179 yr by Whitigir Report
April 28, 20179 yr comment_763117 Swapped in 6CA7 from Electro harmonic and the sub-bass is better ..... Tubes rolling is fun and GG is amazing ! Thank you Kevin !!!! Can't thanks Kevin enough The LED switch is awesome from Joe and Ang, 2 tones, so white is my warmed up and warmed orange is operational Report
May 13, 20179 yr comment_764465 How much should we bias the EL34 ? Is it 20 mA like the Carbon, or more 25 mA, like the many designs with EL34 ? Or personal taste ? Report
May 13, 20179 yr Author comment_764467 18 to 20ma guitar amps will bias them much more, but they run at only 400v total Report
May 14, 20179 yr comment_764492 I noticed that it will drift from 20-21mA from cold to warmed up. So far it is stable and running great Report
May 14, 20179 yr comment_764531 2 hours ago, Laowei said: Are you using the servos? Yes, opto Servo is engaged. It settles much faster than Carbon does, and is more stable with offset and balances values as well. The only thing is the current which may slowly drift upward from 20mA to 21mA, but then it stays stables over hours without problems and heat dissipation is not an issues Report
May 17, 20179 yr comment_764845 Hey Vince, mind if I tap into your build experience here? I'm working on a GG with joehpl cases. I believe you wrote your amp was without hum. For your umbilcal cord, did you do anything more than twist the heater AC wires together along with scramble bundling the others carrying DC supplies? Report
May 17, 20179 yr comment_764860 I only tried to separate the AC heater as far as possible using the empty pins for spaces on the umbilical cord and as far away from other wires as well for the PSU cable wirings, I twisted the AC heater together with ground wire and the other wires twisted in pairs, and cover them in a braided shielding and a sleeve. You can also overkill this by using a huge aquarium hoses and cover these 3 to create spacer away from the rest of the bunch. I don't care for a flexible PsU cables, just as long as it work great. I did not use the hose though The main hum problems should be from the main AC that may get too close to other wires, especially input-output. Just as long as you manage to keep them away from those, you should be safe. That is just my experiences Edited May 17, 20179 yr by Whitigir Report
May 19, 20179 yr comment_764985 my personal experience is no hum，but I twisted all the ac wire including umbilical cable Report
June 3, 20179 yr comment_766358 On 1/2/2016 at 0:30 PM, kevin gilmore said: zener needs to change to 18v Just powered up my GG amp and was having issues with the offset. Going over this thread for possible clues, and just now saw this note by Kevin. I stuffed that spot with the 12V zener marked on the PCB. Should I replace with an 18V? BTW, found the source of my offset issues. Since the 10M90S are structural, I built them up with the angle brackets leaving them loose to align the tubes thru the tight clearance holes in top cover and forgot to solder them in. Doh! I earlier set the CCS at 20mA with the LV supply, without B+/B-, so I thought things were good. Fully powered up with tubes, set the balance and tried to set the offset and the best I could measure were left: -60VDC, right: -243VDC. Finally found the problem after some trouble shooting. Soldered them and everything is running measuring good ATM. Will try with music and my SR-009 soon. Report
June 4, 20179 yr comment_766379 The voltage there was 10.xv as I recall. Change to 18v will avoid clipping but 12v should be plenty during normal usage. Congrats on the successful build! Report
June 7, 20179 yr comment_766651 Not so successful so far. One of the channels is on the fritz. Balance and offset now both skewed in opposite polarity extremes. More troubleshooting to get it working correctly, fitting a huge RK50 and cleanup my mess of wiring before I post more photos here. Edited June 7, 20179 yr by Laowei Report
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.