ckt

Schematic....you may have to print it, to view it right, depending on screen resolution This message has been edited by ckt on 03-11-2002 at 08:12 AM

basic troubleshooting. if you swap the drivers and the problem follows, its the driver. if you want to pay $100 and up, for troubleshooting, take it to a dealer.

Most of the multi-media systems for computers are crap. I can't beleive that some of the older companies in audio have put their name on these systems. Its probally because the average person can't tell any real difference. I do a little bit of audio editing, some home recoding, some remote live recoding, and have done some clean up work for a local TV station. What I found out, when I first got into it, that the consumer sound cards are not up to the specs they claim. Some of the most popular brands can't handle moderate levels of high frequencies without generating audible IM distortion. I measured a well know brand card one time, and it only had a 75 db s/n - and it was rated at below 90 ! We'll known vendor was not about to replace it. In my quest for a decent two channel audio card for serious audio work, I found a company, Lynx Studio, who fit the bill. The card is more than a lot of folks want to pay, $500. They met their specs and exceeded them. Turns out that several companies use this card for test equipment because it exceeds it specs (s/n greater than 103 db, can push +18 dbm/600 ohms, can be set for -10 for consumer equipment or +4 for pro equipment, 24 bit A/D, and digital in/out, and timing I/O, balanced or unbal analog I/O). And it sounds great. Most of the time I monitor (on the computer/editor) via the old Koss Pro4s headphones. I have an older SAE preamp and power amp on the system (don't see much of their equipment on the used market !) . The speakers are old AR-18s bookshelf speakers. The headphones usually will find any problems and defects, but if I need a serious listen for soundstage/width, I can burn the music on a CD R/W and carry it to the living room and listen on the Cornwall's.

Try Antique Radio Supply (http://www.tubesandmore.com/) They have a catalog that has a ton of books on old radios. A lot of these books are just schematics. Also trying searching on the net.

Hen I was about 15, somebody gave me an old Grundig console - had the SW radio, phono, and amp. Later it was an old Bogen PA amp, Garrard turntable, and a couple of 8 inch speakers from Layfayette (kit). Like several posters, I also played the trumpet and later moved on to bass guitar (which is probally responsible for the 4 db loss in my left ear). My neighbor, a doctor, knew I was into music, and invited me over to hear his system - Cornwalls powered by McIntosh. It was the first system that I had ever heard, that sounded like the band was in the room with you. WHen I turned 21, and got married, the wife wanted a stereo console. I asked if she wanted to listen to music or did she want some furniture (say what?). I found a store that had Klipsch. We walked out with Herseys, a SAE preamp and power amp, and a Thorens turntable. I could not afford the other Klipsch speakers, at the time. The system still runs, and I have added on to it in time. I use to mainly listen to rock and roll, but over the years, I have come to appreciate classical, jazz, and blues. I still like to turn it up, but I find I can't play it loud anymore - the ears will start ringing in about 5 minutes. What I have allways have appreciated is Klipsch could reproduce the spectrum with clarity at about any level (I know the Herseys are a little shy on the low end). I have heard a lot of speakers that get muddy on bass at moderate levels. Some that could not reproduce bells, chimes, and tri-angles. Horns that did not sound like horns. I do not know about Klipschs new line of speakers, but I beleive the reason that the older units did so good, is they were very efficient and you could get away with a smaller amp. Paul Klipsch wrote a "dope from Hope" titled something to the effect, what we need is just a good 5 watt amp. I beleive it! A little humor - when I was in the Philippines, I had a yardboy and maid (about $10 a week for the both of them). The yardboy told me my speakers were cheap, because they were not JBL or any of the other popular Japanese brands at the time! I never told him otherwise as stereo equipment was a very high theft item.

Its good for protection, if an output transistor fails - which in most cases short - which puts the speakers strait on the power supply rails.

I basically lay on my side and drop a small amount of hydrogen peroxide in the lid of the bottle. Then drop into ear. Let it go a couple of minutes and dump out to a towel. Then repeat one or two times, until it does not fizz anymore. Then turn over and do the other ear. Most hydrogen peroxide is so duluted now days, that you can use it strait. My freq response is 300 to 3000 +/- 0.0001 db when I get thru....!

I "boil" mine out about every two months with hydrogen peroxide. I have to turn down the treble about 3 db, after cleaning. When the treble comes up by 3 db - time to clean the ears ! This message has been edited by ckt on 11-10-2001 at 03:11 AM

My first CD player cost $700. The CD's were about $30. I made the classic mistake of turning it up trying to set the volume via noise floor - got my ears ! It lasted about 4 hours. I noticed it had a buzzy sound to it, and I did not pick up on it so quick. I found a test CD, and it really stood out on a single tone. So it went back and I got a different brand - and it was a little better. A lot of the early CD where not that great. I had records that sounded better and I think it was due to tape generation loss that was induced by the time the CDs came out, plus bad A/D converters. I bought a lot of the MFSL CDs, they were alot better. I think a lot of the audio producers like to push the equipment into limits when mastering - they were use to pushing tape past the limits, which was somewhat forgiving. Some of the best CDs, I have heard, have been recorded at lower levels to leave plenty of headroom.

I did not see the article. Wonder if they left the cable on a reel, or did they spool it off and spread it out? And how did they match for testing purposes ? Ironically, there is a trend in audio transmission for long distances to use a very low impedance source and a medium terminating impedance. It gives a lot more bandwidth than matching. Come to think of it, its kinda the same for an amp and speakers. Most amps have a very low source impedance. I reckon thats why we had all the discussions on damping...

you can check it with an ohmeter - it will probally read below 8 ohms - dc resistance of the speaker is allways lower. the crossover can have problems, too - such as a inductor or capacitor going open.

A lot of zip cord is sold with one conductor tinned to use for polarity purposes. Also some zip cord may have a flat edge on one conductor and a round edge for the other conductor. Usually if a copper cable has problems, it tends to get very dark (starting to oxide) and sometimes develops a green corrosion.

We'll, from what you described about it helping, the power line must have a lot of trash on it. The isolation helps by not providing any path thru your system. The SOLA I described also gave isolation. I noticed it dropped the hum level quite a bit, when I was using it in the Philippines. Since I moved back to USA, the power is very stable and I could not tell a difference using the transformer (I live about 1 mile from a major power substation - so they power is very stable). I keep the transformer on my electronics bench now, and if I run into an old AC/DC radio, where the power line is directly coupled to the chassis, I use it. I also use it when I am working on microphone and phono preamps as it makes everything a little bit quiet when making performance measurements with test equipment.

Its probally a ferro-resonant transformer. Several companys in the US make them. I used one (a Sola 500 watt unit) while overseas, as the power was very unstable. One night the lights went just about all the way out for about 10 seconds and the stereo just kept on going with no change in the sound. But, the transformer sure got hot making up the voltage difference. Our voltage was allways low, around 105 volts. It was not uncommon for it to brown out to 60 and 70 volts. Most audio power amps does not have a real voltage regulator in the power supply. So at high levels the voltage drops down due to the increased load. The more load you pull, the more voltage drop on the wall outlet wiring back to your electrical service entrance. Basically you are regulating the voltage to a constant level at your amplifier. If the voltage is low to the amplifier, it will not be able to develop full power. We don't need full power, but we need the peaks to be clean. By regulating the input voltage, you are insuring that the amplifier will have maximum dynamic range. Let me point out a couple of problems with the voltage regulator transformers. Some have a high THD on their output (Sola low distortion unit is 3 percent - I think their normal unit is around 15 percent). Also, the transformer needs to be located as far away as you can get it. It can induce a very large magnetic field, enough that you can hear it on a turntable pickup or tape head if it too close. I had mine mounted about 18 feet away from the system. This message has been edited by ckt on 08-13-2001 at 04:37 AM

After reading again, I realized he was talking about summing - I went to delete my own post and thats not allowed ! Mr Moderator, a user should be able to delete his own post ! You have option for it under editing !

Its not good on the amp - also, you will be left with the difference of audio between the channels. Anything common to the channels will be cancelled out ! Back in the "old" days this was the way they made a psuedo surround sound for the rear channels. The rear speakers were put in series with each other and connected to the left + and the right + on the amp. But, it also had the normal left and right channels for the front.

Around late 60s. A Bogen 50 watt tube PA amp. A 8 inch coax speaker and cabinet kit from Lafayette. A hand-me-down Garrard turntable (think is was a lab 55) with a cheap Shure cartridge. The Bogen was also abused by my bass guitar.

About 20 years ago, I bought a set of Heresy's. I broke in the wife, kids, dogs, and neighbors with them. They sounded alot better about 40 hours later because everybody was running for cover.