JMCMAN

wisconsin

unfortunately I do not have an oscilloscope.

Stray voltage= 0.35 ac volts measured on main preamp out to amplifier the voltage will change if I lower the bass tone control to 0.1 ac volts, likewise if I use the high or low filter a slight variation in voltage. the preamp is close to original the only changes were a new rectifier and volume control.

I have a Marantz 7C preamp that recently made a sound like a car engine revving up. Quickly shut it down. After looking inside the preamp I noticed some stray voltage when using the high line input selected. When I switch to low line level it zero's out. Not sure where to look for bad resistors or capacitors or switch in that high line input circuit. Any help would be greatly appreciated. thank you

Did your Speakerlab folded horn plans call for any stuffing in the rear woofer chamber, or did you use any ? Yes the plans called for 18sq ft of 1" thick damping material, but after read some posts about stuffing I decided not to use any.

JMCMAN:Here is a pair that I built using only the bass bin speakerlabs plans. They sound great. Nice Horns! WTH are those mid and tweeter horns and drivers ? Crossover ? On your plans, did you use the speakerlab driver for bass ? Did your plans call for any dacron stuffing in the rear chamber of the woofer ? Okay, to answer your questions about my horns. The mid horn I built and modeled after the Fostex H200 with the Klipsch K55 driver, the tweeter is the standard K77. For crossover the ALK universal network. The bass driver is the Bob Crites standard replacement for the K33. With a sound testing CD I am able to go down lower than the Klipsch Khorn according to Klipsch's specs. I am very pleased.

Here is a pair that I built using only the bass bin speakerlabs plans. They sound great.

Thanks Mike, the sound is coming from both channels. Any safety precautions needed when checking filters? Jim

I have isolated my problem to my amp. With nothing connected to my amp ( no pre amp ) I get a hum (while tubes warm up 10- 20 seconds) that turns into a midrange sounding tone that is constant. I have checked all the tubes over and replaced two weak tubes ( 12AX7, 12AU7) one of the output tubes shows weakness in the life or filament test but reads okay otherwise. The sound does not change when I turn the output gains down all the way. I could use some advise as to where to start looking for a problem. Jim

Thanks Bob, I did not use the same midrange horn, just the driver. But the upstream equipment is the same. So the hiss was there all along but I didn't know it. BTW I'm using your woofers in the bass bins. The sound is very good. Thanks again Jim

The hissing is in both tweeters. I notice that the E type reverses the positive and negative, whereas the A tpye does not have any components out of phase. Maybe I should have one component out of phase? Jim

Last night I had the pleasure of hooking up my Khorn's that I built. I used the tweeters and midranges form my heresy's. I also converted the Type E crossovers to the Khorn A type. I heard a hiss from the tweeter, and was wondering what could I do to remove that hiss? Any ideas? Jim

I noticed on my Heresy's a small cone that covers the tweeter screen. My question is if I am placing a K-77 or CT-125 in a wood horn that I made for my Khorn project do I need to have a cone covering the screen on the K-77 driver? I have attached a picture ( I hope the attachment works ) so you can see what I am asking about. Thanks