Scott Grammer

As far as I know, these are original Klipsch oil caps. The crossover is a real Klipsch type B, and the caps look to be fully original. They still measure fairly well.

So my 1968 Cornwalls are still dead stock, except for adding crimp-on connectors to the wires connecting the drivers to the crossovers. These were in storage for about 20 years, and have just now been put back in service. All screws tightened, crossover caps test OK but not perfect. A couple of solder connections have been touched up. Here's my question: I kept noticing a particular frequency, if excited by whatever music I was listening to, would be extremely resonant and bothersome. I knew it was in the upper mids, but over the weekend a little spectrum analyzation and a little tinkering with a parametric EQ and tone generator have narrowed it down to approximately 2,300Hz, and it appears to ring out about 8-10dB louder than the rest of the midrange, in both speakers. Any suggestions as to what it could be and how to fix it? The Q of the resonance is so high that on certain songs one does not hear it at all, while other songs are unplayable because of it. Thanks in advance for all responses.

OK, just a warning: To enjoy this, you must: A. Like metal. B. Have a sense of humor. C. Turn your volume up LOUD.

Boy I know that's right! That's why I tell my clients it should only be done if absolutely necessary. Time = money, and so recapping is EXPENSIVE.

Thanks, I appreciate any help offered. I have one in my shop for for service, and I will be doing a full recap on it. Three of the four filter caps are leaky (two are showing bulging seals), and several randomly-chosen caps on the power amp and power supply regulator boards are off-spec. It would be a lot easier to put together a parts list for ordering the smaller caps if I had a parts list, which would be part of the service manual. I can work from the schematic, if I have to.

Thanks, but that's just a schematic, and an incomplete one at that. I had downloaded that one and found a better one before posting. I actually need the full service manual, if I can find it.

Hey, if anybody knows where I can find a complete service manual for a Concept 16.5 receiver, I sure would like to know about it. Anybody? Anybody? Bueller?

Not only The Band. RR was a great producer of other artists' work. For instance, RIP, RR.

Push-pull tube amps that use negative feedback, such as, for instance, the Dynaco Stereo 70, can have fairly low output impedances. It's single-ended amps with little or no NFB that tend to have high output impedances, but this is not necessarily a problem, especially with speakers designed with higher source impedances in mind. Some speakers really open up in the bass with a higher source impedance. Unfortunately, some speakers have a problem with these amps, or more accurately, some of these amps have a problem with speakers that have a highly reactive load, as their output will tend to rise and fall with the speaker's impedance.

One more young artist and I promise I'll be quiet. This is Josh Turner.

Lawrence is a brother and sister duet that has really taken off in the last few years. Check them out.

IMHO, this video represents (1) a wonderful performance of a song that I never really cared for before; (2) a great recording thereof, and (3) another amazing example of the work of one of the most talented young people I have ever seen. Check out Allison Young's channel, https://www.youtube.com/@allisonyoungmusic.

When I tore down my "CCAR" (Cheap Chinese Amp Refit) to begin redesigning it the way I wanted, one of the first parts I planned to get rid of was the twenty-nine-cent volume pot that originally came in it. I was amused to find that this crappy volume pot had a very hefty, nicely-machined solid-aluminum knob about 2" (50.8mm) in diameter, with setscrew, attached to it. The knob didn't even fit the knurled shaft of the pot. Now it sits firmly on a nice, full-sized, smooth-turning Alpha Electronic stereo volume pot.

I got to use a pair of those in a live sound gig once. Very impressive, and they inspired me to build a slightly smaller set of W-bins for my own sound reinforcement system. Somehow, I feel they'd be a bit out-of-place in my current one-bedroom apartment. I don't think they'd even go through the door.

I don't doubt it, but those speakers are bigger than my apartment....

Yeah, that explains why I look so big in photos! It's the lens! (J/K) 🙂

My lord, those things are HUGE. A Mac 275 is not a small amp, but those speakers make it look tiny!

It has been my recent experience that the interaction between the amplifier (in this case, three amplifiers, one of which has been tried with two different types of output tubes) and the speakers can have a serious effect on the sound of a speaker which presents an unusual load. My '68 Cornwalls do just that. They swing from a low of four ohms at very low frequencies and at the trough between the two bass resonances, to a high of nearly 70 ohms in the midrange. My SE tube amps don't care much for that, but my SS amp cares not one whit. Still, changing from EL34's to 6L6GC's in my "CCAR" tube amp makes for a pretty decent sounding system. The 6L6's have a lower plate impedance, which makes for more current output. There is still some shrillness in the mids at certain frequencies, but that has been noticed on all the amps, and so I expect it is either the response curve of the midrange drivers, or it is due to the interaction between the speakers and the room. I'm not sure which it is.

In order, I'd say: 1. Room 2. Speakers. 3. Recording quality 4. Amplifier (although, unless it's a really sorry specimen or the speaker exhibit an unusual load, the amp should not have a major influence) 5. Preamp 6. DAC (unless it too is a really sorry specimen).

Right now, I have the speakers returned to dead stock, save for the addition of crimp-on connectors on the crossover end of the wires connecting the drivers to the crossovers. Tightening the woofer bolts also seems to have made a considerable difference in the bass. They still don't sound quite like what I want, but the "vocal-forward" sound is growing on me, and as I said, the bass is improved since tightening the woofer bolts. I'm going to leave them stock for now, until I can decide on a course of action that I feel sure will result in an improvement. Also, I changed the output tubes in my CCAR amp from EL34's to 6L6GC's. These have a tad less output, but they also allow for a lower output impedance, making it easier to drive the 4-ohm woofers. I like the sound better than my SS Nikko. One thing that has struck me since tinkering with the toe-in of the Cornwalls: these things image like no one's business! My JBL's NEVER imaged like this. I think it's due to the fairly narrow dispersion of the mid horns.

I know I'm a bit late in answering this, but maybe I can help. First, you need to make very sure that your amp uses a common ground between the two channels. A call to the manufacturer's tech support or a look by a COMPETENT technician will answer this. If it does, then here's a very "old-school" way of doing it. It's not ideal, especially for dissimilar speakers, but it will work with similar speakers. If you try this, do so at your own risk. I have not verified that your amplifier uses a common ground between channels, and SOME amps do not like having speakers connected in any unusual fashion. Connect the positive leads of the left and right channel speakers to the amp as usual. Connect the negative leads of the left and right speakers together, but NOT to the amp. Connect the positive lead of the center channel speaker to the connection between left and right negative leads, and then insulate this connection well. Finally, connect the center channel negative lead to one of the negative connections on the amp. A 25-30 ohm, 100 watt potentiometer wired in parallel with the center channel speaker can be used to turn it down if it's too loud. DO NOT try this with the usual dinky "home theater" center channel speakers. Ideally, all three speakers should be identical, but the Forte's and the Heresy are similar enough in design that they will probably work like this.

Yeah, the OPT's surprised me with their sound, although their measurements are a bit wacky. The 4-ohm tap is not at 4 ohms, more like 3, and the HF is lacking. With no NFB, it begins rolling off at 13KHz. But the bass was stellar. Flat down to around 10Hz! I imagine the primary has a great deal of inductance, which would explain both the lossy highs and the excellent bass. This one was not a kit, it was prebuilt. They had the primary of the OPT's wired backwards, so the ultralinear tap was at the wrong percentage of the winding. And the suppressor grids of the EL34's were not connected to anything! Just left floating in space. Finally, with an 8-ohm load on the 8-ohm secondary connection, the primaries are the wrong impedance for EL34's, actually better matched to 6L6's. I'm currently running 6L6's in that amp, and they sound pretty good with mt Cornwalls - better than the EL34's in the picture.