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Technics FAQ: "Frequently Asked Questions"

This FAQ has two sections. The first is composed of FAQ elements that answer questions about the site itself. The second is a more technical set of Q&A elements that answer questions I receive about the Technics components themselves.

Click Here to jump directly to the "Components" section


Section One: About the Site


Q: How should I configure my browser to best view the Technics Classics site?
A: Your display should be set for high-color. 24-bit is best, 16 bit is ok if that's the best your machine can do for you. 256 color looks awful (we tested it!). The pages were designed with an 800 x 600 display in mind; smaller will make things look a bit compressed and weird, but it should work. You may have to scroll to see some of the images. Larger should work just fine.

Q: What criteria are used to classify items as Rare, Scarce, etc.?
A: These ratings reflect current and recent availability. The estimates are a compendium of what shows up on the online auction systems, in the .audio newsgroups for sale, and so on. The ratings are not related to the number made, or if they are, it is only through the current apparent scarcity of an item, meaning that if there were few made, we (naturally) see few for sale now.

If something begins showing up, the rating can be changed.

Q: Where do the images on the site come from?
A: For the most part, from EBay auctions and web sites around the net. We've gotten a few from contributors, some from scanning brochures, and I own quite a few Technics components and have used images of those units as well. All images have an attribution line under them that describes the image source.

NOTE: If you run into an image here on the Classics site that is also contained in an auction on EBay, do not assume that the auction is misrepresenting what they have.

First of all, I may have just pulled the image from that exact auction (although in that case, it should have a "caption" under it that says so... )

Secondly, many people don't have access to digital cameras and/or scanners, or they may simply not have an image of any kind. There's nothing wrong with posting a general image of the correct unit in a sale or an auction. Remember, you don't get the unit you see in the audio catalog, either!

If you're in any doubt and you truly think you have a reason to be concerned, e-mail us first to ask where the image came from. I can also check the date of the image and tell you when it was put into the database's file system (or when I last edited it.) Then, knowing the answer, you can make an intelligent decision about what to say to whom.

Whatever you do, do not hassle the seller in any way until you ask me if I got the image from them. That's just mean and thoughtless.

Q: Hey! That's my image! Can I get credit?
A: You bet. Again, absolutely.

If you spot an image you know was yours, just let me know, and you'll get credit. Nothing would please me more than to acknowledge your photo(s). No harm was intended, and only images that (a) had no copyright claimed on them and (b) had no digital watermark I could find have made it into the database.

If I have a conflict - two people claiming credit for the same image - I'll give both credit and you can fight among yourselves. I have no interest in conflict, only in increasing the accuracy and detail of the site.

If you want your image removed, I probably will do so without much ado, though I wouldn't think very highly of such a request. It benefits no one, and hurts users of the site until a replacement can be found, which in some cases may be quite some time. Then again, I might not - as I said, all images were collected from non-copyrighted venues and were free of watermarks as far as I can tell.

Q: Can I link to the pages that describe an item or items I have for sale or auction?
A: Yes. Absolutely. Please do. All images came from the web and were without statements of copyright when they were collected, or else came directly from a contributor to me. If you can, since you physically have one of the units on the page(s), check what you see there to make sure I have it right. We both want the pages to be as accurate as they possibly can be. If you find an error, use the link on the unit's page to send the corrections to me and I'll have them up there ASAP.

Q: Can I use the images here on the site in my sales and auctions directly?
A: Yes - but make sure you copy the image onto your own image server in order to do so, and if there is a credit to a source, make note of that credit in an obvious and easily noticed manner.

Without a credit, you may run into an irate photo-source/owner... most don't react that way, but some do, and they are within their rights if they have taken the time to make sure there is such a credit.

Regarding the placement on your own server, this is very important, otherwise, my poor little web server has to struggle to produce the image every time someone looks at your sale or auction. And I thank you for the courtesy.

You'd be well advised to link to the specific page for the unit, as well - there are tons of specs and feature details that are often not clear from an image, or the description you had time to write between eating dinner and watching the evening news...

No matter if the image is credited or not, you probably want to note in your sale or auction that this is an image of the correct model, but it's not your particular unit. This prevents any questions (appropriate or not) from being raised about the quality of your sales and auctions. Everyone will appreciate your candor.

Q: Can I use the database entries here on the site in my sales and auctions directly?
A: Yes - but you must provide attribution to the classic-audio site in this form:

Technics information copied from
<a href="http://www.classic-audio.com">http://www.classic-audio.com</a>

...which will look like this in your auction or sale:

Technics information copied from http://www.classic-audio.com

Place this line after the copied information.

It is also acceptable to create the link such that it points directly to the page where the data was taken; for instance, if you're auctioning off a TX-9500-II tuner, then you can point directly to the TX-9500-II tuner page instead of the root of the site.

That's all I require, but I do require it! If the data from the site is quoted and this attribution is not included, I will either contact the seller, or site hosting the sale or auction, and request that this attribution be added or the offending item be removed.

It is not acceptable to take the information on site here and use it in any manner that would give any viewer the impression that this is your own data, either directly or by omission of attribution.

All database formatting, indexing and textual content of this site is copyrighted, and any use of same must comply with the description here.


Section Two: About the Components


Q: Where can I get service and/or owners manuals for my Technics?
A: Service manuals for many Technics units can be had from A. G. Tannenbaum's. There is a link to Tannenbaum's, among other useful things, on the Links Page.

Owner's manuals are extremely rare. In most cases, owners learned how to run the gear and then discarded or misplaced the owners manuals. There are no dependable sources for owners manuals, however, you can sometimes find them on EBay.

Q: What do the Multiplex filter or Hi-Blend functions on my tuner or receiver do?
A: FM broadcasts that are in stereo use the multiplexing system described in the FAQ item just above. As described there, one of the restrictions on the design of FM stereo broadcasts was that it could not affect the ability of a monophonic receiver to receive the mono component of the signal. There wasn't quite enough room to broadcast two complete channels in the spectrum allotted to an FM channel, so the only choice left was to reduce the amount of spectrum given to the stereo signal, instead.

What this does is reduces the amount of signal available for the FM Stereo encoding as compared to the mono (L+R) encoding; as a result, the tuner must have a stronger signal from an FM station to get the same amount of "quieting", or noise reduction, in stereo as the quieting it can achieve with the same signal in mono. If you'd like to try an experiment so you can see this happening, just tune to a moderately distant FM station. If you have a hi-blend or multiplex filter function, turn them off. Set the tuner or receiver to mono; and then pay attention to the amount of noise on the signal. Now set the tuner or receiver to stereo - notice how the noise level increases? That is the direct result of the FM stereo encoding being a less powerful portion of the broadcast signal.

When noise occurs in an FM signal, the way human hearing works ensures that it is most objectionable in the higher frequencies - to put it another way, we are more annoyed by a quiet "hiss" than by a quiet rumbling.

In order to allow weaker stations - in other words, the noisy ones - to be listened with the benefits of stereo, the FM multiplex filter (sometimes called "Hi-Blend") mixes the higher frequency portions of the mono signal (which is stronger, remember) with the midrange and lower frequency portions of the stereo signal.

As an example, one result of this would be that a struck triangle (a classical instrument that produces a very high and clear bell-like sound) that would have been mostly in the left channel will instead appear in the center of the stereo field. However, a guitar chord or kettle drum (these are mid- and low-frequency sounds, respectively) will appear properly positioned in the stereo field.

Because the high frequency component of the stereo signal is not fed to the output of the tuner at all, neither are the objectionable noise components. The end result is a better quality stereo signal from the weaker stations. When you switch the multiplex filter on, you should be able to readily hear higher-frequency components of the signal move to the "center stage", while mid- and low-frequency components remain normally separated.

Generally, you would only want to use this function if you are hearing high frequency noise when listening to a station in FM stereo. Otherwise it should remain off, or you may be giving up high frequency stereo separation available on strong signals for no reason.

Q: What does the FM Multipath function on my tuner or receiver do?
A: When an FM signal reaches your tuner or receiver, it is important that the signal is received directly from the station - think of it as looking right down a flashlight beam. FM signals can reflect, just like that flashlight, off of certain types of surfaces such as metal buildings and even geological rock formations. When this happens, the reflected portion of the signal has traveled a longer distance to reach your tuner or receiver, and this causes the phase of the sine waves that make up the signal to differ from that of the direct (non-reflected) signal.

Since the two types of signals are traveling over different paths, the term "multipath" was coined to describe this condition concisely.

The reflected signal mixes with the direct signal at the receiving antenna, and the combination of the two is what reaches your tuner or receiver. From basic algebra we know that when you add two identical waveforms that are out of phase with each other, you get a third, new signal with a new waveform shape - which, in the case of FM reception, means that you are receiving a signal that now contains a distorted representation of the audio component within it. That, of course, is not what we want to be listening to.

The FM Multipath options on tuners and receivers allow you to either hear, or see, the component of the signal that is out of phase. That, in turn, allows you to direct (turn or aim) your FM antenna so that the amount of reflected signal is as small as possible as compared to the direct signal. This results in the least possible distortion when your audio system presents the recovered FM audio to you.

In the case of a "listen-to" design, the button is usually a momentary push-button This means you have to hold it in... it will spring back immediately when you release it. That is because the designers felt that you would not want to listen to the distorted (reflected) portion of the FM signal. It may also have been done, I believe, so that they would not get calls about the "audio being distorted" from customers that had somehow accidentally left the button depressed. It would be more useful if it stayed depressed, because some users have to cross the room to reach the controls that turn their antenna rotators, if indeed they have such gear (highly recommended, by the way!)

In the case of a "see" design, either a meter of some sort or an oscilloscope display is used. With these, you simply adjust for the least amount of displayed signal. Usually the designers of the tuner have allowed you the option to leave the oscilloscope or meter in the multipath measuring position, because simply viewing the multipath component doesn't affect what you hear at all.

Q: What is "Dolby FM"?
A: Note that this explanation is simplified, but fairly accurate. Here goes...

Dolby FM is a system where the broadcasting station modifies the transmitted signal to contain more of the treble frequencies - the higher pitches. These are the same pitches where the "noise" is most objectionable. So when the FM signal arrives at your FM receiver, it still contains the same amount of noise, but more of the treble signal components.

Then, when this signal is processed by a Dolby decoding system, the total amount of treble is reduced according to the limits and methods of the Dolby technique, and as the treble is reduced... so is the noise!

Since there was more treble in the first place, and in just the amount that it is now reduced, the signal now has the original, correct, amount of treble, and less noise - because the noise is high frequency and it gets reduced right along with the real treble information.

The 25 uS de-emphasis switch changes the receiver or tuner's method for receiving FM to allow more treble through, but that is only a portion of the Dolby noise reduction method. The rest of the job requires a Dolby Decoder module, which is a fairly complex device. If you turn on the 25 uS de-emphasis switch without the decoder, you just get more treble... and the signal is no longer correct. Worse, if the signal is even a little bit weak, it will have more noise than it should.

For Dolby noise reduction to work properly, you need these three things: the proper de-emphasis (25 uS),the Dolby decoder, and for the station to pre-emphasize the signal using the Dolby standards at the time it is transmitted.

As far as I know, there are very few, or no, stations using Dolby processing at this time. So this feature is generally not of use any longer. Unfortunate. It worked very well.

Q: What does an "Antenna Attenuator" switch do?
A: It's there for people in environments that are very near a broadcast station's antenna. If you're really close to a transmitter, it can affect reception all across the dial in a negative way. This could be another FM station or even a transmission from a utility service such as police or fire radios that are very near to the receiving antenna for the FM tuner.

With the switch on, the attenuator reduces the signal strength of every signal coming into the tuner, effectively moving all the stations further away.

In an urban environment, where most stations are close anyway, this usually eliminated the problem of the too-near transmitter(s) and left the other stations perfectly listenable.

In a more rural situation, where you're trying to receive stations that are further away in the first place, using the attenuator can make an otherwise listenable station unlistenable - but if you're suffering from severe interference, this may be your only option.

This kind of interference usually occurs in the receiver's front end and mixing stages, before the IF stages, so even tuners like the ST-8600 that have good adjacent channel rejection characteristics can suffer from this problem.

If your tuner doesn't have an attenuator, you can make one or buy one. A really good solution is to pick up a Magnum Signal Sleuth, which is a purely linear device that preselects signals before it gets to your receiver's mixing stages. Check out the review on the reviews page for more on the Signal Sleuth, including links to the manufacturer. I have no connection with them other than being a very satisfied owner of one I purchased from Antenna Specialties.

Q: Where can I get the factory wooden cabinet for my Technics unit?
A: Factory cabinets are rare. In most cases, units were purchased without the optional cabinets.

There are no dependable sources for cabinets, however, you can sometimes find them on EBay.

Q: What does the "DC" designation of some components mean?
A: The "DC" designation refers to the fact that this preamp, amplifier or integrated amplifier can amplify signals over a much wider range than non-DC designs. Here is why that is useful:

The sounds that most people can hear from their stereo are created by speaker surfaces that are being forced to move back and forth by precisely controlled positive and negative surges of current driven through them by the audio amplifier. This occurs at rates of from twenty times a second, to as high as twenty thousand times a second.

For the slowest rates (20 times a second), the amplifier has to correctly amplify these slow signals; if it does not, the sound that comes out of the speaker will be different than the sound on the audio source. Many amplifiers do a fairly poor job of amplifying such slow signal changes - they are designed to cover a wide range of signals, but at the edges of that design, the amplifier's performance limitations begin to affect the signal adversely.

The reason that designs like this are marketed successfully is that most people cannot hear very well, or at all, at the outer limits of their hearing range (20 times a second, or 20 Hz, for instance.)

DC amplifiers, preamplifiers and integrated amplifiers are designed to be able to amplify signals that are much slower than the 20 changes per second that you can hear if your hearing is very discriminating. They can amplify signals at 10 changes per second; at five; at one, and even signals that don't change at all! That last type of signal is a special one called a "direct current" signal, or "DC" for short. That's precisely where the term "DC" comes from when you see "DC amplifier" or "DC Preamplifier".

This example should serve to explain the term DC a little further. If you connect a battery to a lamp, the battery steadily provides a current that does not change (until the battery runs down, of course.) A DC amplifier should be able to respond accurately when a battery is applied to an input - the current output to the speaker should then change until the amount of amplification set by the volume control is reached, and then stay there. Note that you would definitely not want to actually try this, as it is not good for the speaker at all!

The idea of a DC audio component is not to actually amplify a direct, steady current, but rather to extend the amplifier's ability to correctly reproduce a signal so far below the 20 changes per second it needs to that the 20 changes per second is no longer at the "design edge", and so benefits from the same benefits as the majority of the middle range of reproduction does.


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