Multiplex Tuner Repair


Hi Folks,

As most of you remember, I was having trouble with distortion in my Scott multiplex stereo tuner. In mono it's good but while music plays in stereo, there's a good deal of distortion. I took it to a local technician but they had it running through a $10.00 receiver and speaker system. I mentioned to the tech that the problem was most noticeable with classical musical (honest) but they balked and said they didn't find a problem. By the way, after I paid the bench fee, I again mentioned a Scott Multiplex Charger and their two technicians said they never heard of that.

So now I'm at home with the 350 tuner and experiencing the same issues. I live in Cincinnati so I'm wondering whether or not someone near enough to me could fix this tuner the right way?

Also a proper FM antenna might help as I have changed stations and it becomes a little more listenable. I could purchase a Magnum Dynalab ST 2 and bracket it to the brick facade of my apartment building but I don't know how to ground it to the inside of my flat. As mentioned previously, mono sounds great and my thought is that it is getting enough reception in mono but not so much for stereo? At this point I'm frustrated and disappointed in the technician that I took it to.
goofyfoot
Two questions:

1) in your apartment building, are the window and door frames made of metal, as these frames are often regulated to be in most major cities? If such is the case, no indoor antenna will ever bring in the stations in stereo halfway decently. Sorry ... that's the physics of it. It may also be that the classical station does not broadcast at a particularly high wattage.

2) what are you presently using as an antenna?

Rich
Hi Rich,
I've got threads going on about basically the same thing so thank you for being patient. Yes, Ive got metal window frames in this building as it was built in the 1960's. The station wattage shouldn't be too much of a problem, currently I'm listening to a weaker station that's further away and it's clear in mono. The tuning meter gets buried to the right when I have the classical music station on and mono sounds beautiful but stereo is a nightmare.
If the fm tuning is slightly out of alignment as well as the multiplex, could this explain an inconsistency between stations? My other thought is that classical recordings can be very delicate with a good deal of open space surrounding the instruments which could be the reason why the problem becomes more noticeable.
What it comes down to is that this is my first tube engineered component and so I'm learning a lot in a very short period of time. I'm enamored with the tube sound so far, I have it fed into an ASR Emitter II Exclusive. What's frustrating is that I replaced the 4 multiplex tubes with all Telefunkens and 2 of them are military grade so I'm impatient.
Sorry Rich I forgot to mention that I've got a single Monster 12 gauge copper wire on the 300 ohm antenna screw and that's connected to the thinnest wire of a TERK Edge without a power connection. No ground, I take it out of the window sill if I anticipate a storm.
Thanks!
What I suspected ... metal window frames. In three words ... lots of luck.

You need an outdoor antenna ... window sill placement can be iffy, roof placement would be ideal. Can not imagine your building being ok with attaching anything to the facade, that is usually a municipal violation, as facade attachments are associated with falling bricks.

If I include the years working with my dad in his TV repair shop that had tin ceilings, no less, then this has been my experience for the past 50 years. I have given up on using receivers, all together.

Will your building allow you to place an antenna on the roof? Does the local cable company provide antenna hook-up?

On the plus side, you have good mono reception.

Rich
I have good mono sound and bad stereo sound. I have good mono reception and good stereo reception according to the meter. My thought however is that my stereo reception needs to outshine that of my mono reception but I am at a point where I don't believe the issue lies in reception alone.
The window sill is cement and it's possible that I can bracket an MD ST2 to the sill but I need to bring the ground into the apartment somehow. For what it's worth, the upstairs neighbor has a satellite dish mounted to the front brick facade.
I appreciate your familiarity with this Rich, can you give me any suggestions as to how I might ground the MD ST2 dipole?
It is all about reception. It may help to view the reception dilemma in the following way ... if several people were throwing balls at you at the same time ... it would be easier to catch one ball (mono) as opposed to two or more balls (stereo) at the same time. Also, the balls would not be thrown to you at the same speed. That is what you are asking your tuner and antenna to do and produce audiophile quality sound, at the same time.

The easiest thing to do and the one thing that would have the best chance of succeeding is to ask your management company if you can install the following on the building's roof, AnntennaCraft FM6 .

If the building already allows FIOS or DirecTV or Dish Network to install antennas on the roof, this type of antenna should be allowed.

The physics behind this is simple ... an antenna which has a direct line of sight to the radio signal will do a pretty good job of reproducing the sound.

The MD ST2 is very similar to the old style car radio antennas that were mounted vertically off to the side of the front or rear hood. That is pretty much how you would install this antenna.

You could place the antenna in a vertical position in a room corner near your tuner and see if it improves the situation any. Bracketing a 5 foot antenna vertically to a window sill may catch management's attention though. The ground, I believe, can be attached to a radiator, pipe, or outlet box.

My focus on management attention is because I am a coop board president and deal with this fairly often, as NYC takes facade attachments very seriously for multiple dwellings ... a $2500 fine per occurrence if outside of NYC regulations.

Rich
Thanks Rich, the MD ST2 is likely the first and possibly only option, as the landlord would probably object and getting to the roof would involve a good deal of risk. As I mentioned before, the satellite dish is on the brick facade, the front of the building and not on the roof, so they wouldn't care in the least about a dipole antenna. I can place the antenna in the direction of the signal easily as my building faces in that direction but I need to ground it to something inside my flat.
From the installation instructions for the , MD ST2 :

If the antenna is installed outdoors, it is recommended that the cable be run through a ‘static discharge unit’ or ‘grounding block’ that can be connected via a ground wire to a nearby earth ground, such as a grounding rod or water pipe.

Can you run the ground to a fire escape or other metal on the outside.

Rich
Being a newer building, this is one of the few buildings in Cincinnati without a fire escape. In fact, if I had a fire escape, I would put an antenna on the roof.
The cable lines are somehow grounded, so I'll need some time to look around to see what I can find.
You can get a ground source on the screw that is on the face plate on an electric outlet in your apartment. I think you will be wasting your time and money installing the ST2 only to find out it is not any better than a simple ribbon antenna. If the tuner sounds good in mono why not just listen to it in mono? When I get a noisy station I listen in mono,that's what the mono switch is for. Stop spinning your wheels and enjoy it the way it is.
Yogiboy, I appreciate what you have to add but I believe you're over simplifying. The intention from the start was to make this a project of no half measures. If there is nothing to be done to improve this tuner, then I will stop investing in it but I haven't yet reached that aggregate.
Maximizing my reception capability is only a small part of what's being considered, the tuner also needs to be aligned.