Recent content by SPEC2man

Mr P, You old softie. Great story, I had a similar experience but my friend ended up dieing on me. It was a sad tale but I was so glad we reconnected and got back into music. Doug and I had 10 great years together and I was there for him at the end. I'm amazed at how strong that friendship...

Did anyone else make it to the Christmas tree? I feel like I earned something ...

Great article, I had always heard the name "Ahmet Ertegun" but never fully understood his contribution to so much of the music I love. I was aware of Jerry Wexler and I even toured the studios of Muscle Shoals. He had his fingerprints all over Muscle Shoals Music and Fame Studios. Funny how...

Hey, did someone say " AV garage unit, cement floor, canned beer sparkle? I'm IN !!!

I swapped the tubes from the good and bad amps - I didn't apply power due to the fact it was 95 degrees and the garage was unbearable. I will test them out Sunday morning - I have the bias turned all the way down and will let them warm for a few minutes before I touch anything, If they stay...

Thanks for the information, I have a set of KT-120s but I haven't cracked the boxes yet. In addition to the Mac 75's I'm also running Quicksilver V4's - hence the need to stockpile lots of output tubes. I bought the KT-120's for the V4's. I think the V4's will even run the KT-150's but I'm...

Funny you mentioned that, I was sitting drinking coffee watching the sunrise and that very thought popped into my head. Of course - use the good tubes from amp A and see how things roll in the suspect amp B. I'm an idiot - my troubleshooting skills have 25 years of rust on them. As for the...

Picked up a quad of kt88's for my Mac 75's - I will use one of the old pairs (working perfectly) to test the MKIII. Interested in hearing the new Telefunken KT-88 - spendy little buggers. O'h the sacrifices we make for our brothers.

This weekend I'll pull a fresh pair of KT-88 and see if the issue repeats itself. Step by step ... there problem is in there somewhere. Worst case - I buy the new driver boards and have at it. I'm slightly intimidated but I'll have time this fall - I have one more 150 foot fir tree to deal...

Well it's not great news ... I plugged the second amp in with no source, I let it come up for maybe 45 seconds, I checked the bias - it initially showed 5.3 volts - so I killed the power. Nothing got too hot and the tube heaters did start to light up. I double checked the bias pot and set to...

I got the bias set and the amp ran for 3-4 hours straight. Seem to distort a bit at high volume but that might just be normal and I'm not sure of the age of the Gold Lions I plugged in. I will have my brother purchase a new set of output tubes - I stuck JJ 12AU7's and EH 12BH7's - if he wants...

The good amp is up and running - tested for 1-2 minutes no signal. Then hooked it up and ran it for 2-3 songs. Sounds great. Time to check the bias. Is it as simple as plugging in the meter with banana plugs and measuring 1.56 VDC?

I checked the picture and proceeded : The good amp has a new precision bias resistor, 1000V 390pf capacitor installed, 1 K resistor soldered back in place and the electrolytic cap is soldered back in place. I'm going to fire it up - any last words of wisdom? I have the bias pot turned all...

I think I finally have the time to do some work. My brother is coming over tomorrow to check my progress. Attached are some pics - The first picture is the jumper I soldered in, to tie one of the electrolytics to the trace. I think it should work. The second picture is of the bias...

I have all the stuff and I am going to dive in a bit this afternoon. One of the bigger electrolytics came lose and it looks like the end of the trace has disappeared, so I need to take the lead as it pokes through the board and extend it 1/6 of an inch to meet the trace. It's going to be...