DizRotus

Space Cowboy, I found "How to Service Your Own Tube Amp" by Tom Mitchell a useful primer on tubes. It's available from Amazon.com. I've enjoyed getting my feet wet with a Dynaco SCA-35. It's spartan by comparison to other tube gear, but it's a leap over the SS receiver it replaced. BTW, if you think NOS stands for New Old Stock, you're wrong in this case. NOS440 refers to Craig's 440 cubic inch Camaro that runs nitrous oxide. Craig is a man of varied interests and talents. Craig, please check out my post on Squealing 7719's. I'd like your advice regarding testing pin voltages. Regards, Neil

lynnm, NOS440 & mdeneen, Thanks for the input. To answer mdeneen's questions, yes I replaced parts, but no I did not change circuits (unless replacing the multi-stage electrolytic can capacitors is changing circuits. In any case, the oscillation problem manifested itself before I changed anything other than the Sovtek 7199 tubes. I was hoping that the new parts might solve the problem, but no such luck. In the interest of full discloure, I bought the fibergalss cap and output boards sold on eBay by John Sullivan. I used his suggested parts list to replace the can capacitors. The output boards received all new coupling caps and resistors of the same value. Only the two ceramic disc capacitors on each output board were re-used. They tested OK, and I could not find modern equivalents. I also installed ceramic tube sockets. I'd like to take the advice about measuring pin voltage, but, as a tube tyro, I'm not certain as to how to do it. I assume that the negative lead of the DMM is attached to the chassis and that the positve lead is sequentially touched to the pin terminals, with the DMM at the proper settings. If my assumption is incorrect, please let me know before I destroy the amp, the DMM or myself. Has anyone had experience with the cap replacement sold by John Sullivan on eBay? If so, what are your opinions. Is there a better alterantive to forty-year-old can capacitors? NOS440, someday I'd like to drive to Burton to check out your new La Scalas and that Camaro. Now that my kids are too old to get excited about a ride on the Huckleberry Railroad, I don't get up that way often, but I would make a special trip to meet you and get some expert tube advice. Regards, Diz

As my first venture into tube gear I have restored a Dyna SCA 35 to drive Heresys. Everything went well until I replaced two different brand 7199 tubes with Sovteks. Upon powering the unit, with the volume at zero, there is a squeal from the speakers that varies in pitch and volume and sounds like a doppler demo. It lasts approximately three seconds and then everythingg is fine. If the unit is turned off then turned back on within a few minutes it does not happen again. After the unit has been off awhile the noise returns when first turned on. I experimented by replacing a single Sovtek with one of the old 7199's. The squealing returned in both channels as long as at least one Sovtek was in either channel. What gives?

Thanks to one and all. The information is right on target.

Guy Landau, Thanks! Those are just the kind of sources I'm looking for. Similar suggestions from others are still welcome.

I'm finally getting around to restoring some old Dynaco tube gear. In addition to Parts Express, Antique Electronic Supply, Triode Electronics and Radio Shack, what are some mail order and/or online sources for the resistors, capacitors, etc. that would be needed to restore vintage tube gear? No one place seems to have a full range of parts and a few of the oddball parts are not at any of the places mentioned. Thanks for any suggestions.

SIX SIDES TO A CUBE, i.e., SIX POSSIBLE WAYS TO BE LOADED INTO A TRUCK.

HDBR, Now that I think about it, riding on their backs in the FedEx Ground trucks from San Diego to Michigan would have been the safest position, as the weight of the assembled motorboards would have tended to hold them in place against the glue blocks. Riding on their faces would have hade the opposite effect. Of the eight possible ways they could have been loaded into the trucks, only face down would have prevented the weight of the motorboard assemblies from pulling against the glue and staples. My speakers have cosmetically rough cabinets so their is no reason to preserve ariginality for the sake of collector value. The components are in excellent shape and the speakers sound great when the motorboards aren't flopping against the glue blocks. Therefore, I will remove the old glue and reglue and secure the motorboards with 1 5/8" #6 drywall screws located at the sites of the old staples. The black phillips heads of the countersunk screws make for a neater appearance than the bare wood divits and exposed staple heads in the black motorboards. Those exposed staple heads always looked bad to me, even before the motorboard came loose. I realize that the glue alone should hold the motorboards in place and that the staples merely served to temporarily secure the motorboards during assembly, until the glue set-up. Nevertheless, the screws and glue eliminate any possibility of another loose motorboard. Based on your comments, I will resist the temptation to seal the horns to the backs of the motorboards. With the motorboards and backs securely in place, I'll assume the enclosures are "air-tight ENOUGH" to satisfy PWK. Thanks again, Neil

HDBR, Thanks for the reply. Unfortunately, I can't post photos, as the 60 gig hard drive in my primary computer crashed. This old back-up computer lacks the programs needed to retrieve photos from my camera. The glue blocks seem to be solidly attached to the sides of the enclosure. A rather anemic "glue line" is evident on the surfaces of glue blocks. It was obviously not enough glue to hold the motorboard in place (the speaker probably rode on its back in the FedEx truck when it made the trip from San Diego to Michigan). I will take your advice regarding the reattachment of the motorboards in both speakers. Neil

I've seen the Heresy described as having an "airtight" enclosure. In reality it seems far from it. The removable back does not appear to seal tightly. One of my 1982 speakers had the motor board (I was surprised to see that it was merely stapled to the cleats inside the enclosure)pull loose. I removed the staples, put some thin foam weatherstripping on the mounting surface for the motor board and used drywall screws instead of staples. While I was at it, I put the weatherstripping under the back panel too. There certainly are fewer air leaks now, but without sealing the tweeter and squawker to the back of the motor board, the Heresy is still not "airtight." All of that undamped plywood on the interior, the lack of seals between the horns and the motor board and the removable back is unlike most other "sealed" speakers. Would Heresy speakers benefit by being truly sealed and by having the plywood panels dampened? Last, has anyone else experienced the stapled motor board pulling loose? Given the construction of the rest of the speakers, those staples are a shock.

I have the E Network schematic. In adition to the 33uF cap, there appear to be other changes. For instance, the wire from tap 2 on T2A goes to the positive lead to the squawker on the E2, but to the squawker's negative lead on the E schematic. I would like to see the E2 schematic. Thanks for your help.

There was a typo in the original post. The year on those Heresy speakers with "X" in the SN is 1982.

Does anyone have the schematic for the type E2 Network in my 1985 (SN 145X559)Heresy?

It has been suggested that the vertical orientation of the tweeter and squawker horns in some CW's produce a better soundstage. Has anyone tried modifying other Klipsch speakers with vertical horns? EV used vertical orientation of the horns in their speakers. It appears that the horizontal orientation used by Klipsch was a compromise to make the design more compact, to reduce material costs and to facilitate construction. As my wife could attest, there are very few things in our home that have not been modified--I say improved, she says modified. I'm a tinkerer. For proof, got to http://members.aol.com/ROTUSROTUS/Specs.html to see a car that I built. I'm not afraid to break eggs to make an omelet. The 4 Speakerlab SK-horns I used in '76 in a mobile DJ business had the T-35's in a vertical orientation next to the metal squawker horns. I would occasionally put 2 of the 4 SK's on their sides so that the floor and the wall became the "corner." The bass remained good. That makes me wonder what would happen if the K-horn bass units were placed in the wall corners but on their sides so that the wall becomes the floor. The squawker and tweeter horns could then be placed vertically, with the tweeter on top. They could be moved away from the corner while being kept near the bass unit. The potential benefits could include: better imaging, felixibility of placement (no longer restricted to firing at 45 degrees) and less visual domination of the room. The recumbent bass units and the narrow profile of the vertically oriented horns, might stop people from asking why the wooden refrigerators are in the corners of the room. Due to the crossover point from the bass to the squawker used by Klipsch, the mid/high horns could not be removed too far from the bass, but there would be more flexibility of placement. If the benefits of vertical horns are genuine, they could be also applied to Heresy and La Scala as well. The modifications could be done in ways that would not prevent returning the speakers to their original configurations. Unlike eggs, the Klipsch drivers could be safely returned to their shells. Now the dangerous part begins. As I'm typing, the thought occurs to me that a larger bass horn could be designed to utilize more of the wall or the floor. The bass units could be designed and constructed to extend from floor to ceiling or to extend for more than ten feet, if placed along the floor with the "bottom" placed in the corner of the room. The modifications I suggest are more practical than the concrete bass horn buried in the audiophile's yard that teriminated with the mouth being the entire end wall of the listening room. A simple experiment could be performed by someone with access to 4 Heresys. With one pair on their sides on top of the other pair, the woofers could be disconnected from the upper speakers and only the woofers would be connected to the lower pair. What do you think? Neil a/k/a DizRotus

HDBRbuilder, Congrats. I'm glad they're going to a good home. Due to the misspelling, I wondered if true Klipsch aficionados were aware of their availability. It bothers me to see Klipsch speakers (most frequently Heresies) dismantled and sold piecemeal on eBay. I trust that you won't pillage those classics. Please share the details of the condition. Even if none of the drivers is operational and the cabinets were destroyed, you still got a great deal.

The seller misspelled Klipsch when listing these La Scalas. If I were close enough to avoid shipping. I'd bid higher on these. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1346230788

Can you go blind from replying to your own post? The record cleaner post reminded me of a cleaning system that I used and liked in the past. While confirming its continued availability from Old Colony Sound Labs, I discovered a plethora of calibration CDs. The web address is: http://www.audioxpress.com/bksprods/cdindex2.htm If you are unfamiliar with Old Colony, you might find it interesting.

Years ago I found a collection of old 45's that were essentially un-playable until I used the cleaning system from Old Colony Sound Labs. After using the cleaner, most of the records were almost like new. It works like a facial. It also makes the records less subject to static charge, i.e., they tend to stay clean longer. There are other things at the Old Colony site that would interest most visitors to this forum, especially the DIY types. Lest you wonder, I do not have any connection with Old Colony Sound Labs, other than being a satisfied customer. The address is: http://www.audioxpress.com/bksprods/kits/km-9.htm Texti.e.

Years ago Shure had a record called "Audio Obstacle Course" with which one could confirm speaker phasing, left/right balance, etc. Does anyone know of a similar CD? On a simialr note, what is your favorite CD for showing off your Klipsch speakers to the Bose refugees?

NOS440 That's OK. The passion is good for the hobby, so long as the discourse stays civil. I wish I could go to Lima.

Mdeneen, Thanks for the reply. This is just the sort of advice I was looking for. Always love an excuse to get more tools. After reading several tube-related posts, I see an EICO in my distant future. But, for now, I will experiment on the SCA-35. The only modification made to the current SCA-35 was a new three conductor power cord grounded to the chassis. As soon as I get another SCA-35, I will start by "restoring" it with upgraded parts. When it is in service, I will experiment on the existing SCA-35. As a prodigal kit builder, I enjoy the journey as much as, or more than, the arival. Your offer of further advice is appreciated and will be accepted.

I just bought a pair of Heresies and a Dyna SCA-35 on eBay to use in my office. They both work fine but I've gotten the tube bug and want to learn how to improve ths SCA-35 before moving on to PAS 3, ST-70, mono-blocks, etc. As background, I built several Dynakits and Heathkits (all SS) in the 70's. I used a Dyna ST-400 to drive four Speakerlab SK-horns in a mobile DJ business. I had an open account with EV for the T-35 voice coils (then $11.00 as I recall) that got fried regularly. Therefore, I know how to read a schematic and solder, but I know nothing of tube gear. My plan is to buy another SCA-35 to restore/modify and on which to begin the education. What tools/equipment would anyone(are you reading this Mobile Homeless?) suggest to add to my multimeter and soldering iron? I ordered the CD with Dyna schematics from Greg Kaufman. For now, I'm not intereseted in Bottle Neck/Head/Whatever and the like. The sound levels from those four screaming SK-Horns did a job on my high frequency hearing. I just want to play with the Dyna tube gear and then listen to the music. Any suggestions would be greatly appreciated.