67 Seeburg SS160

Hello I have a Seeburg SS160,

I have done the following...
Replaced big cap in the Auto speed unit
New motor mounts/coupler
New needles
oiled it according to the manual
Had Bill Bickers rebuild the Amp
adjusted the tone arm weight to 2 1/2 grams
cleaned all points and contacts
added a "free play" box

The right side/B side plays have distortion in the vocal range new or old. The Left/A sides sound great. It has the red tone arm and a Pickering P340 cartridge.

OK--I love to play Jeopardy---ah, I assume the question is--why the distortion only on one side ?
Assuming I am correct about that, I would further assume that the problem lies somewhere between where the mechanism audio cable attaches to the tone arm cradle assembly, and the needle. This could mean that the tone arm wire is "rubbing" somewhere when it shifts, or the cartridge socket is faulty when pressured on one side, or the cartridge is bad on one side , or that needle is no good---
Chance are it's the socket, and /or needle broken, which is common on the red tone arm--I assume that you have read something somewhere, and know the red tone arm on that model was re-called--??
Ron Rich

"New needles" -that is probably the key.

Today we only get copy styli for these carts and they sometimes have defective damping. Most of the copies are made from diamond "splints" which are inherently less strong than a quality diamond.

Nothing new here, in early 1988 I was given several sets of yellow copies. They had awful lower-midrange distortion similar to an overdriven amp.

The tips were Ok and the highs were clean.

If you haven't done so, reverse the styli.

Rob/NYC

Yes sorry, I was asking about the distortion. I had written a more detailed post which was lost in the log in process. Ok so the damping action on the red tone arm has failed. I assume this is why it flops around as opposed to gently setting down on the record? Alright cool. Ron I will be contacting you about a tonearm and mech book. Other than this issue the box works great, very easy and straight forward to work on.

I have new needles i do believe I flipped them awhile back to no avail. Will try now again that there is less variables in the mix. My guess was the socket, cartridge or needle.

Ramblinman wrote:My guess was the socket, cartridge or needle.

Measure the impedance of both pickup channels at the RCA plugs that go into the amp. That pickup should read approx 460 ohm/ch. While measuring, slightly wiggle the cart to check the quality of the connections at the socket -do not touch the stylus while you do this as it will generate a slight voltage and confuse the meter.

There is near zero likelihood that the cart itself is causing this distortion. The coils and magnet structure is common to both sides.

There is also no good reason to change the tonearm.

Trying to diagnose these sorts of problems by "remote control" places us at a disadvantage, but my bet is defective stylus -a problem we'll probably be seeing more-of.

Rob/NYC

Hi All,
As you may know from previous posts, Rob and I dis-agree on this subject. I contend that it is necessary to have damping action, on the Seeburg tone arm. I base this contention on the study Seeburg, and Pickering did, when this style cartridge was introduced, and there were many complaints about "faulty needles". Their conclusion was that without damping action, the needle pressure, at set down, was too much for the needle suspension to handle, and resulted in failure of either the suspension, and/or, sometimes, the needle itself. Seeburg's solution was to redesign the damper chamber, and to "re-call" all of the red tone arms. They offered "free" replacement parts for at least 5 years. Distributors were encouraged to provide an inexpensive service, offering to change/re-balance the arm, if the mechanism was brought into the shop, for that problem. If any of you know anything about "bean counters"--that caused a "war" between them and the "quality assurance" dept. !!
It seems as if I have changed at least 1000 of them--never had a return complaint, so I still advise doing so--
Ron Rich

Which pins are the left and right channel? I tried getting an ohms reading several ways before hooking up to the two front pins and then the two back pins. I say front and back pins in relation to me standing directly in front of the jukebox. I would have thought the two pins directly below each stylus would be each of the separate channels but I only got erratic readings that way or none at all for either set of pins. My final reading one side reads 626 ohms and the other side reads 606 ohms, hooked up to the 2 front pins and then the two back pins. So from my understanding this should checkout fine for this cartridge.

I swapped the stylus around it had no effect on sound quality. I have performed a test recommended by Ron Rich: "One "test" you might try--remove a record and select that "slot--holding the tone arm with one hand, use your finger to put "sideways" pressure on the top of the cart--on both sides--if the cartridge is loosing contact, you will hear a "popping" sound from the speakers".

I did this and I heard no popping at near full volume. I did notice that the records do not get clamped fully by the clamp arm/turntable. the shaft the turntable is on has some play in it, 1/8th of an inch? at most. could the record grooves be at the wrong angle due to this causing the distorted sound. Sorry I know its hard to make a diagnosis over the internet. The suggestions so far have been very helpful.

'rambler" The pins on the sides of the cart at oblique angles to the styli are the correct points and as you note, the only places to get readings.

I dug out four of those carts along with my list and all were in the 460-472 ohm/ch reading so yours do seem a bit high.

In a more normal phono preamp this would not have potential to matter, in these Seeburg amps the cart is part of the forward bias voltage divider for the first stage. Higher impedance can cause too much forward bias and push the transistor into it's nonlinear region causing distortion particularly on loud records.

A couple of things to check:

I assume the tracking pressure (2 grams) is set for both A&B sides.

If you have a turntable with magnetic cart, try plugging that into the amp (w/machine in-play of course) How is the sound? Also try plugging the juke's RCA plugs into your stereo amp's "phono" (magnetic) inputs.

Locate C5143 (100mfd @12v). This is the AGC time constant. With the amp lugged in and muted you should see approx 9vdc on this cap. When a record is playing this voltage will decline to a point where the signal level from the record will control it. Typically for a loud record this will be at/near 2 vdc. If you temporarily touch this voltage to chassis ground the machine's level should get louder if the AGC is functioning correctly. If this voltage does not vary with record loudness or can not reach even 1 vdc it is likely that the AGC is not working correctly and this will cause distortion. While this would not account for the apparent difference in levels between record sides, I suspect that something is being overlooked here and without having the machine in front of me we have to take these roundabout tactics.

Rob/NYC

Ramblinman,
Couple of thoughts--needles, if "aftermarket" may be some of the problem, as is the lack of damping. Amp MUST be a TSA-5 code C, at least, or you WILL have some distortion problems. If C43 is still the original brown paper cap--change it, as most are no good. One other thing--speakers on the SS-160 model are "critical"--if you do not have the original speakers mounted as shown on the speaker itself, all "kinds of things" may happen--
I just read two carts--all readings were in the 485 ohm range--however, this may depend on the meter used to read them, and if it was done through the socket, or directly on the cart. itself--which is what I did--
Ron Rich

Thank you Rob and Ron, I spent some time studying the Mech and noticed that the B side record play position the stylus was jammed too far right. the spring mount on the tone arm was upside down and not putting tension on the arm at all. I flipped the spring around and re checked the pressure and now the really noticeable distortion from the B-side is gone it sounds very close to the A-side when playing the same song in either position. There does seem to be some mild distortion on both sides of play. I do not have a new record thats "full range" enough to really test if its a record quality issue or if its something in the jukebox. The new records I have are re-issues of 50's rock and 60 surf/fuzz, lots of distortion in the music to begin with. There is a clunking sound as the record turns and the sound distorts during this, I going to try and adjust this out first.

I had Bill Bickers do a full rebuild of the amp, he replaced all the caps, but I will check out the AGC. I will also check the resistance at the phono inputs and check the amp with another turntable and speakers. The speakers are original to the box and mounted correctly as far as I know. Can I hook up just any speakers to this amp? It's a TSA-5, or is there a certain Ohms rating that must be maintained? The speakers are original to the box as far as I know.

Thank you Rob and Ron, I spent some time studying the Mech and noticed that the B side record play position the stylus was jammed too far right. the spring mount on the tone arm was upside down and not putting tension on the arm at all. I flipped the spring around and re checked the pressure and now the really noticeable distortion from the B-side is gone it sounds very close to the A-side when playing the same song in either position. There does seem to be some mild distortion on both sides of play. I do not have a new record thats "full range" enough to really test if its a record quality issue or if its something in the jukebox. The new records I have are re-issues of 50's rock and 60 surf/fuzz, lots of distortion in the music to begin with. There is a clunking sound as the record turns and the sound distorts during this, I going to try and adjust this out first.

I had Bill Bickers do a full rebuild of the amp, he replaced all the caps, but I will check out the AGC. I will also check the resistance at the phono inputs and check the amp with another turntable and speakers. The speakers are original to the box and mounted correctly as far as I know. Can I hook up just any speakers to this amp? It's a TSA-5, or is there a certain Ohms rating that must be maintained? The speakers are original to the box as far as I know.