| Author | Message | ||
| thefishingline |
I just picked up a a Music Man HD 130-210 to match my other one. I have a couple of questions. 1. I have two of the same amps. Is the lower serial number the older of the two? I notice the size or font of the numbers on the dials are different in size. 2. The one I already have sounds great...as does this one I picked up yesterday. However...the one I already had is much hotter and louder when all control dials are set exactly the same. The tubes on the louder one I can't tell what they are as they are silver and I have to remove the back to see...while the output tubes in the one that is not as loud are clear and labled Sylvan, CA tubes model number ET-E34Ls...any ideas which were the original tubes in the HD 130-210 and why these ET-E34Ls may not be as hot as the others? Would love to speak with some one on the phone about this. 516-889-6895 or e mail me your phone nunber and I wil call you. rjohnson@thefishingline.com | ||
| thefishingline |
Is anybody home? Would love to see more folks here. | ||
| Langley |
To compare both amps to each other, 'ya needs a level playing field. Bring both amps to a tech - who understands MusicMan. Just like when buying a used car, get them bench checked. Figure at least on a couple of hours of bench time and new tubes. These amps are 'mature' and often require TLC and $$$ to make them 'whole' again. Tubes and biasing may not be the only issues requiring address. Therefore, I strongly suggest that you seek a qualified and reputable tech to execute any repairs. (Check out the postings here. Some excellent technicians post here regularly.) But, FYI... The tubes that you mentioned - E34LS are from Svetlana, relabled by Groove Tubes in California. The E34LS's have a higher output rating than most other EL-34's. They require a slighty higher bias setting. Sounds like you've a cold bias, relative to the the requirements of the EL34LS's. A cold bias value may cause the tubes to run cooler and also create crossover distortion (this may be the 'clarity' issue you mention). Re., the other amp, thats 'loud and clear' I really can't comment on that one with the info at hand. It might use 6L6's instead of EL-34. (EL-34 is the european #, 6CA7 is the US #. Not exactally the same tube.) It might be biased correctly or 'more than correctly'. I can't tell from here. And please don't hesitate to come and ask questions. We like 'em. And we're home. But, we wake up - when we wake up. | ||
| thefishingline |
Great answer...my tech guy is none otehr the Jess Oliver of Ampeg fame. The first one an the hotter of the two we'll call #1. That was bench checked a year ago and has been a great amp, clean and distored ever sinces. This new amp #2...has what looks lik ebrand new tubes and wityh all levels set the same is no where near as loud at the same volumes as #1. I am seeing Jess in the morning and getting them both looked at (reverb in #1. no wher near as good as the new amp #2) and have this set up so both amps wil be the same. He did mention I may 6l6's in the # 1 amp. What is biasing the amp mean? i have we'll call | ||
| thefishingline |
By the way..can oyu answer my otehr question I had on the difefrence between 210's and 212's inthe otehr forum thread I started ? | ||
| Langley |
Amps amplify sine waves. Sometimes sweetly clipped ones  In a 2 output tube amp, one tube amplifies the bottom half of the sine wave while the other tube amplifies the top half of the sine wave. (An amp with 4 output tubes will have 2 tubes assigned to each wave half.) It's preferable that the top and bottom of the wave have the same wave form. Having matched output tubes facilitates that need (although a slight mismatch can often sound nice...). Setting the bias means aligning top and bottom halves of the sine wave adequately. It's like setting your car's idle. Of course, theres more going on in the amp than I've stated here... ----- The difference between 210 and 212? I have to answer "2". A 12" Celestion Vintage 30 sounds different than a 12" Eminence Legend, while some 10's may spec out like a 15". It all depends, so use your ear. (The 212 has a larger cabinet than the 210 which will probably add some bottom end.) __ My regards to Mr. Oliver. Tell him R.C.A. Institute is out of business. No more evening courses. And "Kirchoff" isn't something guys do in the shower. | ||
| thefishingline |
I showed Jess your note "My regards to Mr. Oliver. Tell him R.C.A. Institute is out of business. No more evening courses. And "Kirchoff" isn't something guys do in the shower." It rang a bell but he couldn't put his finger on it and requested to know a little more about who you are |
Tue, 03/25/2014 - 09:57
#1