Quote:
Originally Posted by Electronic M
Pure class B audio should theoretically never exist. It always has to be at least slightly into class AB in order to prevent highly noticeable/objectionable crossover distortion, and I can't imagine any properly working piece of audio gear that would be designed to be pure class B.
My radios are both newer designs having ICs in the output and tuner stages. The one in that link looks like an early 60's design that was modified to allow for a tape system to be added.
I tried the switch on the stereo unit, and I can't definitely locate it in the Quad unit.
I don't have a source of proven caps for transistor gear, and don't have an ESR meter to check what I have so a shotgun recap would likely just create new problems....Also the troubles are somewhat intermittent which makes signal tracing/injection trouble shooting a must.
I've maintained several home 8-track decks and a healthy collection of tapes for over a decade now so I know what that entails. I collect recording formats, and love messing with an unusual format or mechanism. Also I know many shortcuts such as ordinary clear scotch tape and or super glue to fix the foil splices (less than a 10 minute job for me.)
I listen to 30's-80's popular music almost exclusively so most of what I care about is represented, and I have a home deck so if I don't have or can't find what I want I can just dub a new tape. I also have cassette to 8-track adapters (some of which I view as poorly as you view 8-tracks) of varying quality. With one of those the machine becomes dual format, and if I add a one of those CD to cassette adapters (you know the 'cassettes' with the 1/8" stereo phone jack coming out of them) the number of formats I could attach becomes only limited by my desire to do so.
My big problem getting a correct schematic was that the model numbers were obliterated on my units, but I got a good idea since my last post....I looked up my machines on ebay (since they are both factory correct options for my car it was easy), and lifted pictures of the model #s, and from that found that they are in sam's AR-228, and AR-333...Now to find someone with those manuals that don't want 44$ for the pair like the sam's web site does.
BTW it was not until the model year after my car was made that Lincoln started offering cassettes in that model, and not until the early 80's that the quad 8-track units stopped being offered despite quad being essentially dead in the market place by the time my car was made.
|
I have a friend who has a 72 Lincoln Mark IV with the factory 8 track, in his the radio doesn't work but the 8 track does, and he is always listening to the same couple tapes. His is maroon, with a maroon and white leather interior. It has a Cartier clock in the dash! I have offered to repair it for him if he can remove it, I can't imagine being stuck without a working radio. Then again he only drives it on nice days. I've been preparing a script in my head for the eventual conversation "if you ever want to sell your Lincoln, please keep me in mind!" Hes a car collector so things are always coming and going but I know he especially likes the Lincoln. It's been way too long since my driveway was graced with the presence of some Detroit iron!
Yes of course the transistors won't be biased into full cutoff, or like you said crossover distortion would be abysmal, but they're also not exactly biased into the most linear region of the transistor either, because if they were it would harm efficiency too much.