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Messages - crystaltech56

#1
I'm operating on the assumption that every one knows about www.goldmine-elec.com. I've had good service from them. Their selection is wide/varied/weird but some excellent prices on some items that we in particular are interested. I'd avoid their "tools"(probably from China,UGGH!), and as always,shop comparatively;but look at their semiconductors and cap's and switches, excellent! Downloadable pdf catalog and update flyer every two months. I am in no way associated with their business, other than as a customer(neutral party). Also check out www.allelectronics.com. I use to work across the street from them in L.A. ; it was hard not to spend the whole paycheck there sometimes; a weird and wonderful selection, but shop comparatively, they ain't saints. Never shop RadioHack again. We should create a list of vendors recommended/rejected or also put an alert section when some vendor has a chip we would all want. Check 'em out. Crystaltech56
#2
One good place to look is www.colomar/Shavano/speaker_design.html. In fact, the entire site is great. And on that particular page, there is another page you should download as well! These used to be called "musical Instrumment speakers", but now are called "musical instrument and Pro Audio speakers", (see how out of touch I am? I'm old enough to remember seeing the Grateful dead play at M.I.T. on May 5,1970 the day after 4 students were killed at Kent State(no I wasn't I student at either place). The guy who did there sound for a while was named Bob Heil ( of Heil Talk Box fame). He has his own site, is still in business, and has a book still in publication,I think it's "Professional Guide to Concert Sound". The book isn't on the site, but I e-mailed him and he sent a phone number(I'll post it later, can't afford to buy any toys this week) to call to order. It really is a great book. Do an Amazon search on it(it is available if you can't afford new) and also Goole "Bob Heil" I'm reluctant to post any of it because of copyright infingement and Bob desreves the money.  CrystalTech56
#3
Yes, excellent reason is you will probably tear the cones off the rest of the speaker assembly the first time you play. Don't despair because inexpensive musical instrument grade speakers are available ( from, and I hate to use this word, RadioShack) and others ( on the web, cut out the middleman). I'll do some more research and get back to you personally, (unfortunately I've been away from the repair industry for so many years I don't know whose in Business still). The point is a hi-fi speaker cone and coil cannot handle the power( unless you want to sound like a cat chasing a mosquito both ductaped in a shoebox with holes). On the other hand, hang on to the cabinet that you have. It's a good staring point. CrystalTech56.
#4
Preamps and Effects / Re: boss dd-3 hums, advice?
April 29, 2008, 01:52:36 PM
This is gonna sound dumb but......some times your easiest fixes will be what you need. Have you cleaned the connections: power supply, input and output signal jacks? Dead serious, since you say it's old. the technique consists of removing all three jacks from the housing (you probably have to remove the board too, I assume you have a clean bench where you can do delicate work) and use what use to be called a "typewriter eraser" to clean all contact points. Also clean the point where the power supply enters the board. When I say clean, I mean rub off all solder flux with the eraser( sometimes can also use ordinary pencil eraser) then use acid brush to wipe away residue with rubbing alcohol. Clean your input and output connector jacks as well, then put new flux(micro amount!) and reflow solder on it carefully. Old solder flux can breakdown and become conductive, and corrosion can grow around all three connectors causing ground loops and internal oscilations from out of no where. At the same time clean and corrosion from all three areas. Next step would be to clean large deposits of flux on pc board. Next step would be replacing first capacitor in Power supply input line(not in the plug in power supply, on the device board itself). Remember, work slowly and carefully. Crystaltech56
#5
Amplifier Discussion / Re: Gibson G-80
April 29, 2008, 01:25:40 PM
Have you Google'd "Gibson G-80 amplifier schematic", (in quotes)? It only comes out to one source, and that seems to cover all factory mods,upgrades and generic substitutions. It's $15.00, plus probably a few for shipping,handling so $20 tops. When you're doing work like this, it seems the wisest choice. Plus, there are many sites that have NOS semiconductors, once you've bought the above manual, just plug them in to google(the p/n) and see what comes up. Even if you are a starving student/artist the $20 would be worth waiting for/spending on what seems to be the factory service manual. CrystalTech56
#6
Amplifier Discussion / Re: kasino powered cabinet
April 28, 2008, 09:22:09 PM
I know you'll hate me for this, but I did see some Kasino Amp schematic/service manual reprints on Ebay recently. I say I know you'll hate me because I myself find Ebay search engine to be insane-logic(not fuzzy-logic) driven. If I see the actual site I'll send it to you. Crystal Tech.
#7
Hello, I don't see if you conducted the test for arc'n'spark at the in put jack. How did it go? If you did ,and there was no improvement with a) a new jack installed and b) by substituting a new,known good guitar and cable; then it's time to move on to deeper trouble shooting. Questions for you: Do you have a voltmeter or preferably a VOM meter, a small signal generator( 2 or 3 transistor) , some sandstone load resistors, an O'scope? Just asking, so I can more directly answer future questions. Do you have schematic, or is it available on web? Loud hum often means problem in power circuit because some one dropped it and knocked loose a capacitor from it's mount on circuit board, or broke a printed circuit run on the board and now there is no signal but the oscillating of 60 HZ power or another circuit (input volume control on tone), Let us know how it's going. Have you read my "Your Governtment Wants to Help You" post in the newcomers? section? Have you downloaded the manuals? They are free and they are very good. Let us know what equipment  you have to work with and your level of skill; it makes it easier to give appropriate answers.  Crystaltech56
#8
It's the old trial/substitution of a know good device until you come to the bad part. No rocket science here. I'm totally unfamiliar with the amp,but..... First off, disconnect power then examine the input jack for a good soldered connection (a visual inspection, that's why I say I'm unfamiliar with the amp, the jack might not just be visible from the back , you might have to do 30 to 45 minutes of disassembly, which you'ill have to do if the jack itself or the soldered connection is damaged, in order to do the repair). The jack may have been mechanically damaged( it only takes one good pull on the cord in the wrong direction). If the input jack is good proceed to next step: find a known good guitar and cable( proved good on another amp, no noise,  no arc'n'spark ). Connect good cable and guitar prior to powering on the amp ( loud transient noise breaks trons, speakers and you ears. Set volume to one (don't go above two) and give the plug-in-the-jack the "wiggle test" . If you get noise you know you at least have to resolder the jack if not replace it. Maybe it's best not to re-assemble amp in case until this test is done. Good Luck.
#9
I've been away from electronics and the web for several years, so I am out of touch. While surfing I found two guys who know much more than me; so if you want to know "where to begin?" be sure to check their sites out and download appropriate info. www.drewdaniels.com and //myece.ucsb.edu/bobsclass/2C. on the last site, download all datasheets( from the datasheet section ofcourse!) and read them over and over, like 100 times apiece. This will get you in the frame of mind you need for learning to compose the questions that you don't know how to ask yet. Crystaltech56
#10
Okay, I'm a little behind in my schedule. I apologize( in the middle of moving). The book I'm copying them from is about 1972, so I'm not sure about copyright violation. I guess I'll do a few and see what happens. What is the best format to use as an attachment to post to this site?  If you're bored while you wait for me to get it done, take a look at www.swptc.com/mholley/RadioElectronics/Jun1974/RE_Jun1974.htm CrystalTech56
#11
The Newcomer's Forum / BOOKS SECOND HAND
April 12, 2008, 08:55:14 PM
You want books, cheap, secondhand and good condtion; but HOW? Well, whenever you pass a second hand store(Goodwill, Salvation Army and now there are so many Thrift Stores that benefit a particular Charity) go in and look at their bookshelf Books to look for are any ARRL Manual (why? because trons are trons and if you get the yearbook(no matter the year 1952-2008) It will be full of circuits and Tutorials on soldering, construction, power supplies, audo preamp, compressors, etc. (year boo is approx 2.5 inches thick) The one published each year is about $45 bucks(search ARRL website), but you CAN pickup one at a second hand store, charity event Ladies Auxiliary once a year event lawn sale, or any yard sale for probably under 5 bucks. And ARRL has Many other publications including one on op amp design. Also remember while you're ant the yardsale/second hand store to look for RadioShack's build a 35. or 101 or 301 electronics projects kit. It's a big seller at Christmas for $40.00 (see the radioshack website), but you can get it for $2.00 at a yard sale;Quite The Bargain for prototyping! Also, Most Large Public Libraries sell off books that don't circulate much; sometimes once a year at a bookfair, sometimes the have a room set aside that is taffed by a volunteer. I recently picked up what would have been $100 new or near new (second hand book store charge high prices) for $10. Remember tron theory that YOU wan to Learn hasn't change in 50 years, so these reference books WON'T ever become obsolete for you( the librarians think they are that's why the get rid of them). More Later, crystaltech56
#12
Do most of you realize that all manufacturers have their products with Data Sheets and Application Notes ON THE WEB, DOWNLOADABLE in pdf, for absolutely free! The only one they would charge for are stuff less than two years old. AN Application Note is a printable form of documentation that gives you several( if not MANY) schematics and parameters for the use of each chip. As an Example go to the Home page for Analog Devices (I'm leaving for you to Google it as part of this exercise, you want to learn, right?) and look at every category. Learn to use this manufacturer's website. Do a search on AN-347, AN-937, and AN-131. DO NOT BE AFRAID OR INTIMIDATED. YOU CAN LEARN TO READ AND USE THE DOCUMENTS! All manufacturers have the Application Notes(or AN's). It's how engineers pick and choose an item to put in a prototype product to show to management to see if they want to mass produce. Learn to use this! Crystal Tech
#13
The Newcomer's Forum / Re: Crate GFX-212T
April 09, 2008, 10:13:53 PM
St Louis Music (produces of Crate Series) still exists and I think the web site is www.StLouisMusic.com/ so I'll bet they have schematic/service manual available (maybe even free on the site). I know I have the warranty card for a small crate that I bought new in 1989 (never sent it in because I haven't had trouble), so if your search comes up empty let me know and I'll send you the address. Theire ownership may have changed hands(show me something that hasn't in the U.S. in 20 years), but I'll bet they still offer support. I know I have an MPC Guitar made by them in 1975 with a plug-in phaser and fuzz box(each the size of a pack of cigarrettes) and I was able to find the schematic for each of the web. CrystalTech56
#14
The Newcomer's Forum / Help from Your Government
April 09, 2008, 10:05:19 PM
Yes folks Your Government wants to help You! You may not realize it but there is a series of Publications available from the U.S. Navy called NEETS(Navy Electronics Education Training Series); gotta love those acronyms! At any rate, I was a Navy Calibration and Repair tech for ten years, and I have to admit this series is very good for many things including a general introduction to soldering, use of test equipment, and general theory. It's best if you download them at  www.phy.davidson.edu/instrumentation/NEETS.htm. You know the routine; it's in Adobe Acrobat, so shrink your browser down to just show the speed of the down load to make it faster. You can go to several Navy sites too, but they seem very slow. Really, you owe it to yourself to try it, because you already paid for it with your taxes. The series is also available on CD; your local Navy recruiter (both Active and Reserve(there is a difference)) might have a few copies laying around( so call and ask). If you're in highschool, call and ask them to send a recruiter to speak to your ham radio club(why doesn't your school have one? tied into your computer/electronic music club?) and say," ... by the way when you come to speak could you bring 20 copies of that NEETS Module CD? I know alot of guys want to see what Navy electronics traing is really like....", and don't be embarassed because it doesn't cost them. No lie G.I. Real Deal. CrystalTech 56
#15
Okay, maybe this the wrong place to request this :Schematic for Marlboro Soundworks CA-12 Combo Amp, late Seventies vintage. I've only found one users group where I guy admitted he worked for them but then didn't want to talk about it. He said they were a portion of Music Instrument Corporation of America(now probably defunct as well). I apologise if this is the wrong forum; I'll do better next time. I also have some schematics to post, but I'll wait until I see them requested. Gerry Mac(the crystaltech56)