RobertR

I'd be extremely leery about running high level, high frequency sine waves. You could blow output transistors, at an output level well below clipping. They simply aren't designed for this. RR

With a mono signal you can compare your meter calibrations, for one thing, to see if they agree. I have four A-753x amps (12 channels exactly the same as you have two of), and I can tell you that the meter readings are not 100% reliable. RR

Just to cover all the bases, you should be running a mono signal before you conclude absoultely that one speaker blows fuses more easily than the other. Possibly there is something heavier on the left in your test material. Could be that you have internal arcing in a crossover coil. You could swap them channel to channel, one at a time to test for this. RobertR

Everybody's talking about the Bose 901's imaging (Why talk about something they had so very little of?) and the impedance (I think I remember somewhere reading 0.89 ohms each - fairly silly, I'd say) - it doesn't much matter, as long as all the drivers are about the same. A far more concrete problem was what occurred in the mid-1980's as CD's took over the market. The equalizers were not engineered for input levels of two volts, and would crank out terrible clipping distortion on the loudest passages on maxed-out, highest spec modulation CD's. At least my V's (whose foam did disintegrate over a decade go) were like that...had to place the EQ after the preamp's gain control; running in a tape loop they were a disaster. Lots of components had a problem with the higher output of CD's - a good portion of the early complaints about "digital" distortion may have been just the same sort of thing. Many will remember that Bob's Phase Linear 1000 had the same issue, neatly solved by a mod from jvdtexas. RobertR

Actually the old 30" ribbons sounded great, and still do, but they need amp power almost beyond reason to run them to best advantage - real current hogs. The big improvement in the 60" ribbons was output - around 5dB. RR

The original 30" ribbons were a different design from the 60", in that the ribbon material had just two traces - just one time, up and back. So they may well have sounded different. But most of the "sound" (the voicing) comes from the crossover design anyway, and those changed lots of times. Rebuilt 30" ribbons are now done with the 4-trace ribbon - have been for some years now, as I understand the situation. RobertR

Srinath, I mis-read, I guess. If you know where the break is, just use your writer on it, clearing away any excess silver goop that could short two traces together. If you don't know exactly where the break is, an ohmmeter will tell you, but you need a very dull probe and a gentle touch, lest you puncture right through the trace. The following is for you or anyone who needs it: Looking at the ribbon from the front, we see four aluminum traces running lengthwise. Two very close together, then a larger gap for the center magnet row, then two more close together. Counting left to right, call the left-most trace (where the red wire connects) #1. The red wire connects to the bottom PC board and to trace #1. When current enters the #1 trace, it passes up to the top, enters the little PC board there and is routed to trace #3, passes down to the bottom, is rerouted to #2 and goes back up again, to be reversed by the top board again and pass down trace #4, where it is connected to the black wire. There has to be continuity all the way from red wire to black or else you hear nothing. If there is a short between two traces someplace you will have a continuity reading, but part of the ribbon will produce either no sound or screwed up sound, depending on cases. And it also might produce a nasty failure in your amp, because the impedance could go way too low. So check for that 3.6 or 3.7 ohms (with at least one of the two wires unhooked from anything else) - you should be pretty close to that value if all is well. None of the above applies to the problems of loose, buzzing ribbons, of course - that's a physical problem, not an electrical one. RobertR

Yeah - three little bolts with locking nuts. Watch out for magnetism with loose hardware around those ribbons. The contacts are just pressure - they aren't glued or soldered to the traces, just bolted. If anybody could figure out how to solder to the aluminum, the boards wouldn't even need to have contact foils. The ribbon vibrates right up to the edge of the phenolic, so the 4 aluminum traces can gradually get sort of sawed through there. That's why it's a good idea to take, say, a utility knife and when the board is removed scrape its edge a little, to dull the boundary where it contacts the ribbon. Same problem, top or bottom - 8 places in all where the trace can open up; and 8 more in the other channel. As with so many gadgets, the more you work on these things, the more you wonder how they ever f'n work at all. But they do... RR

The break right at the board edge is very common, and the board can be unscrewed and moved aside for repairing the trace - no need to open the ribbon. Before reinstalling the board chamfer its touching edge just a little, and the problem is unlikely to re-occur. I guess the problem of avoiding blobbing silver conductive material across two traces depends on how sharp a writer you have and how gooey the liquid is. It's no big deal, as long as one is aware of the possibility. If you goof up, the stuff scrapes off easily enough when it is partly dry, using a wooden toothpick or match. RR

Srinath, Wish you'd spoken about need for circuit writer repair earlier. It can be employed successfully without splitting the ribbons - much safer, easier, and quicker that way. The stuff really works, but of course you have to assure you don't bridge the tiny gap between traces... The first time I fixed a 48" ribbon with that stuff I put an ohmmeter on it while it dried. Started around 30 ohms and as I watched the reading went steadily down. I stopped watching when it reached under 4 (new ribbon is around 3.6, so not bad). That ribbon worked OK until it was rebuilt a year or two later, for other reasons. You're certainly right about the perils of transport/bumping. The original glue gets brittle and fails. Loose magnets can flip and destroy the ribbon in a wink. There is extra-thin super glue (often available in hobby stores) that can seep into cracks in dried out original glue and re-secure magnets. Tricky to apply, of course - maybe a hypo syringe, handled very skillfully. Some magnet locations are more accessible than others, but maybe worth a shot to forestall a complete tear-down. RR

Srinath, As to your capabilities in re-engineering Bob’s flawed, lousy designs, I did not and will not comment. I didn’t think such nonsense worthy of mention. What I did do was to ask two questions. I got an evasive response to the first and no response to the second. Well then... I have to assume that the answer to both of my questions is NO. One has to wonder why anyone would continue in trivializing the complexities of ribbon repair, as if it were just as easy as changing a flat tire. This strikes me like somebody with a toothache who decides to extract the tooth himself and plans to then perform his own dental implant, all the while saying, "I can do this!" No, you can't. You aren't impressing many here, though I fear you might tempt one or two into nasty mistakes; otherwise I'd just ignore the whole thing... More often than not, faulty ribbons need to be opened up and have the Kapton replaced. But sometimes ribbons have a problem that doesn't require rebuilding, and the rebuilders will let the customer know when they find that to be the case. If the owner tries to open it up, rebuilding becomes the only option, other than $hit-canning. This is why it's unwise to open one’s own ribbon. Fortunately, except for broken magnets, DIY fix attempts on torn up Kapton are not usually an irretrievable disaster, even though the known failure rate to date is exactly 100%. The driver can generally still be repaired - by the same guys to whom it should have been sent in the first place. It might take somewhat longer and cost a bit more, as more magnet breakage can result from opening the assembly. Replacement magnets aren't free and it's a bit messier to get the surviving magnets cleaned up and glued back into their correct places. So there is nothing to gain from pulling your own ribbon apart. Even if you could somehow remove the aging Kapton without tearing it (very unlikely), it is cut shorter now than when it was installed, and there are holes punched all along the edges. There is no place to get hold of it. You will not be able to put it together again successfully. It might just play, at least for a while, but It Won't Sound Right! Getting an old ribbon reassembled and tensioned correctly would be nearly impossible even for a seasoned pro. But you could be the first. Good luck. RobertR

Srinath, A couple of questions on your ribbon work, as I can't help being curious: Did you ever really take that ribbon all the way apart, somehow without totally destroying the Kapton, or did you stop at the point where the picture shows it? Did you ever get that (or any other) malfunctioning Carver ribbon successfully back together again, repaired and working correctly? RobertR

Despite the claims of Parts Express, the Bolander-Graebner ribbons are NOT a drop-in replacement for the Carver type. They simply don't sound the same, period. Get on James Sauter's list for rebuilding - the voicing of the rebuilts is that of the Bob Carver factory ribbons, and the reliability is actually better than new, several longevity tricks having been learned over the years. As to scratch-building your own, anybody's free to give it a try - you would learn a great deal, no doubt. RobertR

It took me several years to figure out to post pictures - problems with my browser, and with my head. I hate it that somebody can do it in less than an hour But welcome anyway! RobertR

What a fun 8 hours of work and worry. In my quest for answers to what this thread started to be about, I was going to first try to edit Window Media Player's settings according to a geek forum person's advice, but it didn't even show up in my start menu's programs list, so I thought it must be flawed, I'd best reload it. Big mistake, turns out. Before anything I asked for was loaded, a lot I didn't ask for was. "search.conduit" and "appbario8" both arrived together. They take over your search engine (I had to search for Google!), add toolbar crap, ads pop up, etc. You cannot uninstall them, or in the latter's case even find it. Conduit gives the appearance of being uninstallable, but it's all lies. The scan that Windows contains ran 75 minutes and found NONE of it, in over 300,000 files. Malwarebytes got a lot of it, but not the last 36 files - for that I had to go pretty deep, guided by a forum, and zap them one at a time. It worked, finally. But pretty nerve wracking. I got rid of appbario8 simply by following the same forum's advice and uninstalling, then reinstalling Firefox, my default browser. And even then, at the last second the bastards tried to sucker me into retaining it. But it all seems to be gone now. BTW, Explorer, Google Chrome, and others are just as vulnerable, I'm told. A couple of very well designed pieces of treachery. RobertR

My HD is a one terabyte that I bought in Taiwan for around $100. I certainly would never dispose of the original CDs; just don't want to haul them to Florida every winter. I plan to back it all up in another drive, just in case. The project is on hold for a while, though, since in trying to download some software for this I managed to snag a nasty, immovable, invasive virus. My next move will be to empty this computer and write zeros on it's hard drive. So I'm signing off for now, for as long as it takes. RobertR

Thanks Greg - I'll check it out. I'm afraid that a lot of the info simply isn't on the intenet, so no program can find it. But still it seems strange that info for different volumes of the same series of CDs would sometimes be available, sometimes not. RobertR

I have plunged into a big project lately, but am having trouble. The job is to rip my entire CD collection to computer hard drives. It should be straightforward, though tedious. Tedious it is; straightforward it certainly is not. The ripping is simple. The problem lies in getting the track titles and other information to load off the internet. The results are terribly inconsistent, inexplicably so. Every third disk or so simply doesn’t work right. Either it is proves to be completely unknown, or the proper title comes up but there’s no track information, or no album cover picture, or no artist name, etc. There seems to be absolutely no pattern to these screw-ups. Big label or small, old recordings or new – no correlation. As often as not I will have three volumes of the same composer’s music, same label, same series, same artists, etc. Two will copy OK, but one will have no information at all, or maybe just the CD name. In another case, within six CD’s of the same person’s albums perhaps half work, half don’t. In one instance Volume One ID’s as Volume Two, including the cover picture and track titles for the wrong CD! Tried on another computer with same results, so have to figure that it’s a general problem, not just my own junk. Some albums ID correctly but give all the wrong songs. In one case (so far) I had a piece that IDs as a different label’s version of the same work, with different album picture, conductor, timings, and orchestra. So what the hell is going on here? I have simply too many disks and not enough time to type in every track. Just the ripping, if it were straightforward, would take me months. I’ve been using Windows Media Player for the job. Would some other program be any better? Or is the information online simply that spotty and screwed up? Computers hate me RobertR

I'd use a pair of Marchand XM-1 two-way crossovers, or equivalent in any good brand. http://www.marchandelec.com/xm1.html You can order them set to any frequency you choose (changeable later if desired). They split the signal quite neatly, with a sharp 24dB per octave cutoff, and no phase inversion. Then your electrostatics no longer have to deal with bass at all, and will sound better than ever in the rest of their range. Getting the system balanced is the only trick, and if neither of your power amps has input level controls you would need to add simple voltage divider pots on the x-over's output of either the high or low signals, depending on which is overly powerful - one is almost sure to overpower the other a bit. When you're all done the whole rig might overpower you a bit, too, as you will have noticeably more power. RobertR

The round things look ever so much like coil forms - spool-like plastic components of a crossover. They or thew copper they're wound with shouldn't exude anything like that. But an electolytic capacitor could, I suppose. More likely some crap from the outside got it. RobertR

I guess that's what these little Carvers are. They certainly sound diffuse. I just don't care to add ambiance beyond what's in the recording, generally speaking, so I seldom use them. RR

When you say out of phase, I guess you mean therear unit's drivers are out of phase within it itself. Or is it a case ofthe rear channel just being a normal speaker hooked out of phase with the frontchannels? RR

So disexual would be what? (Hint: The di prefix is Greek.) RR

There's a lot of presumption in the question. I use no rears at all, though I have a pair of little Carvers here that were designed for that. I think they were the rear part of a mixed set of five speakers, made in the early 1990's, showing no model number. They have drivers firing from both sides. As a rear channel know-nothing, I need help with the jargon. Are they bipolar or dipolar? Bi and di both mean two, to me. RobertR