easyeyes Posted January 13, 2003 Share Posted January 13, 2003 I have a pair of KLF 30s with 10 foot runs on them. For some reason the left channel sounds muffled and isn't as loud as the right channel with the balance knob set a equal. Before, I did not pay very much attention to it, I guess it all blended in together. I received my rebuilt 299A on the past Friday night, after connecting everything that was the first that that I noticed. The right speaker (B-Channel) over powered the left (A-Channel)one. With the 299 I was able to equal this out. Last night the left channel would not play very loud at all, it played but there was static in the sound and again it was not very high. I began to think that it was a problem with the amp, I called Craig and he told me what to do. One of the tubes was not seated properly, this fixed the low sound coming from the speaker, but it did not fix the the unequal sound. Even when I used the channel selector on the 299 (the one to the far right), the right channel sounds good even though it's the only one playing. When I do the same with the left one, it's muffled and less inspiring. I've read enough post on here to know that I should spell out everything, so here goes: I checked and rechecked all of the connections, everything is connected correctly. I rechecked all of the adjustments on the amp and they are according to the book. The only thing that I haven't tried is switching the speakers to see if the problem persists. I have a buddy with KLF 30s and his sounded muffled when connected through his DSP A1, but both channels were muffled. Just wondering if anyone has experienced this before. Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted January 13, 2003 Share Posted January 13, 2003 Try switching tubes from one channel to the next. Do it systematically starting with the 2 power tubes for the right channel switched with the two power tubes for the left channel. Note if problem moved with change. IF not, move back to original location. Retest. Do the same thing with the input tubes, switching channels, done so you can isolate which tube might be the culprit. Hopefully, this is a tube problem. First thing ANYONE should do in this situation is try the easiest solution which is to possibly isolate a tube problem. OF course, the connections/sockets/pots must have been cleaned with contact cleaner. I assume this was done when rebuilt. After that, then other troubleshooting options exist. kh Quote Link to comment Share on other sites More sharing options...
easyeyes Posted January 13, 2003 Author Share Posted January 13, 2003 I'll have the check with Craig on the contact cleaner bit. I switched the two middle tubes last night and the problem persisted. I have to get smarter on exactly what tubes are where. Can't get to it tonight but I will by end of week, this is a busy one for me. EE Quote Link to comment Share on other sites More sharing options...
Mighty Favog Posted January 13, 2003 Share Posted January 13, 2003 So far I think your on the right track. Swapping the speakers left for right is the next step. Or, at least swap the speaker cables. Heck, these things do weigh a little over 100lbs each! If the problem does not follow the swap (the muffled sound still in the same channel then it's something in the source components. If the same speaker is muffled after the swap then it's in the speaker. A tweeter diaphram maybe?? I had a similar problem only I'm using SS gear. It turns out when I rewired the insides of the cabinets I accidently had one of the woofers out of phase. That only took 5-6 hours to figure out . To boot, throughout all this I could have sworn it was the crossover. Quote Link to comment Share on other sites More sharing options...
easyeyes Posted January 13, 2003 Author Share Posted January 13, 2003 In hind sight, I noticed this problem about two years ago when I used my old sony processor. I was just getting it klipsch and the music/ht thing then. I'll try to swapping of the speakers/wire tonight. The new amp made it much more noticeable though. Quote Link to comment Share on other sites More sharing options...
NOSValves Posted January 13, 2003 Share Posted January 13, 2003 Kelly, Yes all the pots, switches and tube sockets were cleaned. This was a complete rebuild and sounded perfect when leaving here so somewhere between here and england something is amiss. I seriously don't think its his speakers . It could be the bias pots were moved during packing and unpacking but I draw a line on those as a reference but I havn't had him check that. This is the second amp to make the jump across the pound and have a small problem. I can see the shock of shipping them over seas is going to be a problem. Please Quit advising people to move the output tubes on these amps this would be the last set of tubes I was would move before moving on to something else. The reason is it can throw the bias off and this person has never biased a amp and it will just cause confusion. I think I'm going to start putting a note in every amp "If theres a problem until I get done trying to work you through it don't post in the forum it just confuses the issue" Once we get stuck then the forum would be a good idea. To many heads are not always better than one Craig PS I just recieved a Email from Ed and he told me he had a similar problem with the previous amp so this may be a speaker problem. I just advised him to switch the speaker terminals so the left channel is powering the right speaker and see what happens. Heck this could even be a room acoustics problem. Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted January 13, 2003 Share Posted January 13, 2003 You have to work on your tone craig. This is absurd. Moving the tubes to the other channel for a TEST is completely FINE Craig. IT is done ALL the time, just to isolate the tube problem. OF course, you always mark where the tube came from to RETURN to their locations. The bias should not shift when moving the tubes. Besides, the amp should be checked for bias after shipment REGARDLESS. This is a TEST and not something that someone should leave. If the bias between the output tubes is enought to harm the tubes, then something is seriously wrong here. In addition, biasing tube amps is VERY easy, especially if you did the bias mod. If you DID do this, then I would hope you included a set of instructions for the simple exercise. I taught my old girlfriend how to bias a Jolida 302b in about 5 minutes. She does it once a month. Again, this should be checked and adjusted after receiving amp from shipment. Instructions MUST be included here (anyone can do it). Again, as a test to see if tubes are a culprit, then moving tubes to opposite channels while noting position to and from is a test done in mere minutes; when completed, if you find the culprit tube, return all to positions noting bad tube. kh Quote Link to comment Share on other sites More sharing options...
NOSValves Posted January 13, 2003 Share Posted January 13, 2003 Well Kelly if you read your post you never advised him of this ! Ed is a great guy but as no experience with these things and needs to be told every detail of these procedures. I never said it would harm the amp in anyway I said it confuses the issues here !! I seem to remember me having a HF-81 here that had the fuse bypassed and you jumping in and telling me to just plug it in. Sometimes I just feel your to quick to the trigger (keyboard) with these things and don't realize that everyone doesn't know what we know !! Craig Quote Link to comment Share on other sites More sharing options...
NOSValves Posted January 13, 2003 Share Posted January 13, 2003 Oh and your wrong the bias WILL shift this is not a self biasing amp this is not a HF-81. Will it hurt the amp NO !! Will it throw the bias off YES !! You are correct the bias does need checking after shipment and he is ordering a MM right now. Your all together to defensive here. The point I'm trying to make and you won't listen too is having to many people advise a complete newbie to tubes isn't a good thing just creates confusion !!! Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted January 13, 2003 Share Posted January 13, 2003 See my email. I KNOW this is not a self-biasing amp like the HF-81 and in my post it discusses the idea of BIAS setting procedure and the need to bias upon unpacking. So why even write this? It makes it sound like I assumed the amp was self biasing (you have told me you do the individual bias mod on 95% of all Scott amps you do a major rebuild). My point is the tube switch is a simple test for a newbie to do. And ONLY a test, not meant to be left in that position. In addition, I think that ALL AMPS with fixed/user adjustable bias should be re-tested after unpacking amp and inserting tubes. I assume you labeled your tubes to go in the sockets you set the bias for. He should still have this labeling with his tubes/amp. In addition, he should be told to have a VOLT METER there for amp setup, especially if a fixed bias amp. ALL manufacturers recommend setting this adjustment again when amps arrive at customer. But doing the tube switch test is a simple newbie operation with the caveat that he keeps the tubes labeled from repair or manufacturer. I assume you did label the tubes to sockets from your test. kh Quote Link to comment Share on other sites More sharing options...
easyeyes Posted January 14, 2003 Author Share Posted January 14, 2003 After further review last night I discovered that none of the above mentioned is the problem. After switching the cables around the muffled sound was still there. I decided to place my ear up against the non working speaker, it turns out that my midrange driver in that particular speaker has no sound emanating from it. Just to ensure that it wasn't my hearing, I placed the same ear to the other speaker. It did not take very much deliberation with myself to ascertain that something was wrong. As stated earlier by Craig, we have talked several times on the phone and other times through email. I apologize to Craig for throwing this on the forum for other's advice without at least determining what the issue was, if nothing else this would have reduced some of the friction that my topic has caused. I know that this goes on all of the time, but I try my best not to post stuff that I can find the answer for on my own or go directly to someone else. Craig, again I apologize for putting you on the spot like this. The problem was there all of the time, the new amp amplified the issue even more. Obviously, since the amp was the latest addition to the mix, the problem would be attributed to it. I have the utmost respect for your talent, ability and time that you have given me with the amp. Mobile and the others I thank you for your helpful hints/advice. Now that the issue is with the driver, can someone help me with this? There are about six screws on the outside of the driver to remove. Is this a simple process? EE Quote Link to comment Share on other sites More sharing options...
NOSValves Posted January 14, 2003 Share Posted January 14, 2003 Ed, Thanks for the kind words. But Apologies are not required. I just feel that questions on the forum should be asked after I have worked thru the problem. Although this thread actually brought the solution anyway. I just would rather not have 12 different people telling what to do to a amp that I am ultimately responsible for especially with you being so new to this type of thing. As far as your speaker goes I'm not familiar with the speakers you have and how to get them open to inspect the wiring to the mid driver but that would be the first thing I would check. It could even be blown which I'm sure is repairable. When you acquire a multi meter let me know and you can give me a call and I will walk you through biasing the amp for the first time. Craig Quote Link to comment Share on other sites More sharing options...
AnalOg Posted January 14, 2003 Share Posted January 14, 2003 Craig As for me being in the technical field I would have to agree with you. It's hard enough trying to trouble shoot on the phone, let alone people making suggestions on what to do to complicate matters. I know Kelly did this with all but the best intentions, but when adviceing one on a procedure you can not assume that they will take all the necessary steps to assure proper procedure in putting things back the way the were, only to possibly complicate the issue at hand. Oh and by the way channel A = left, channel B = right? Tom Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted January 14, 2003 Share Posted January 14, 2003 I could say quite a few things on this matter dealing with this issue since the early days on tube amp interest here. In addition, there are other aspects that complicate matters, again, not necessary to address in public here. I do think it wise to stay out of recommending any fixes, ideas, or debugging with amplifiers coming from Craig. So, in that, we are in agreement. kh Quote Link to comment Share on other sites More sharing options...
NOSValves Posted January 14, 2003 Share Posted January 14, 2003 Yup A = left and B= right goofy that all these companies either named these things channel 1 or A and 2 or B rather then right and left back then huh !! Oh and thanks for the support and yes Kelly always has his heart in the right place and really the advise he gave was correct . I would just rather walk my Customers thru my own process of elimination one step at a time. Craig Quote Link to comment Share on other sites More sharing options...
AnalOg Posted January 14, 2003 Share Posted January 14, 2003 Damn, I've been listening to my music backwards!! LOL! Tom Quote Link to comment Share on other sites More sharing options...
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