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Thorens TD-160 Heavy Buzz

R

r3000

New Member
I had to move my stereo from one space in my apartment to another. I didn't drop or excessively bump anything, but when I reattached my Thorens TD-160 to my Marantz receiver, there was a heavy buzz in one channel (a buzz so loud you can only hear it and not the music...the louder the volume, the louder the buzz).

I have isolated the problem to the turntable (buzz was replicated with a different receiver) and to one channel/cord only (i.e. I can play a record in mono with the other RCA cable which is buzz free).

I looked at the headshell and everything seems still attached. I used deoxit on the cords.

I would guess this is a grounding (?) issue but my understanding of the concept with this particular turntable is limited at best. I am the second owner of this table--the original owner replaced the original RCA cables with Audioquest cables.

Thanks in advance for any suggestions!
 
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I suspect this is not a 'buzz', which is technically a high pitched interference, but rather a 'hum' which is a low (mains voltage) frequency disturbance.
A 'hum' disturbance in turntables is typically a cause of one of two states. No grounding or a ground loop. Since you did not report to have altered any
wiring, I suspect the transportation of the turntable had severed one of the internal ground wires or had shorted it. For reference, have a look at this default
Thorens grounding scheme:

KVNoZaS.jpg


The yellow line from platter to chassis, is in practice a very thin grey wire leading from the middle of the sub chassis to the metal tab in the wiring
hub (see:the original wiring on the left):

6LxGHOi.jpg


The tonearm is grounded via a pinkish thin teflon wire that leads from the wand (attached with a screw and washer), above the pillar to the same
metal tab. It's this metal tab that is also connected to the shield of the right channel (green wire) thus grounding the entire table via the RCA cable.

You can trace your tutrntable ground using a digital multi-meter continuity test, cart pins to RCA plugs. The green pin should beep (close a circuit)
with both the shield (circumference) of the right channel and any metal part on the chassis, including the tonearm gimbals and bearings. The red
pin leads to the live (center) of the right channel, the white is the live of the left and the blue is the shield/return-path of the left channel.

Visually inspect your turntable connections and verify both grey and pinkish thin wires are intact and in contact with the metal tab of the wiring hub.
It would also be wise to tighten the headshell wiring on the cart pins with a pair of long nose pliers.
 
^^ Good info above but maybe you won't have to dig in quite that deep. It could also be poor contact between the headshell pins and the socket. Carefully unscrew the collar (just behind the headshell if you have a Mk I, or along the armtube closer to the pivot for a Mk II) and pull the headshell off. The material Thorens used for those contacts was good quality when new, but tends to tarnish over the decades. Carefully rub the gunk off the pins with a Q-tip and reinsert the connector a few times and see if that helps.
 
Thanks so much to both posters for their suggestions.

On closer inspection, the RCA plug head of the right channel (the one producing the hum/buzz) detached from the rest of the cord (!) I believe this cord was already fatigued and in being plugged/unplugged several times in the move/testing, probably became further so.

Again, excuse my basic line of inquiry, but could a fatigued cord/head connection have been responsible for the hum/buzz?

Also, is it recommended that I change the entire cable (or enlist a more advanced friend to do so) or can the plug head just be reattached (it is an Audioquest cable)?

Thanks again!


IMG_7424.jpg
 
Lop off an inch or so of the old cable and reattach the RCA plug with nice new solder joints. Probably time to do the other one, too.
 
Success!! Had a friend reattach and solder both RCA plugs and the hum/buzz is completely gone! Thanks for all the suggestions.

Somewhat of an odd coincidence, but in the time when the TD-160 was not working, I acquired a Thorens TD-125 MK II when I went to look at what turned out to be a disappointing record collection for sale.

The TD-125 is in good working order and to my ears, sounded great even with a cartridge of unknown age (it has an Audio Dynamic Corporation tone arm). It also seemed a bit sturdier than the TD-160 which is appealing to me as I moved the TD-160 in the first place because of a small child running around. On the other hand, I am somewhat sentimentally attached to the TD-160 because it is the exact model my parents had when I was growing up.

Anyhow, I know I could "google it" but I was wondering if any Audiokarma Thorens aficionados had any opinions/strong feelings on the relative merits on each machine. Is one generally considered better than the other and why? Is one considered more reliable than the other? Thanks again for any thoughts!
 
It's a hum. Congrats on getting rid of it! :thumbsup:

Nothing is more reliable than the TD-160 b/c nothing is simpler. All it needs is to be kept free of grease and oil residue in the belt path, an oiled up bearing and a good condition suitable drive belt.
The TD-125 was Thorens's flag ship model after the TD-124. It is indeed sturdier than the TD-160, it has a formidable thick alloy deck and it's suspension is so effective, it's practically oblivious to it's plinth.
It is also speed controlled by electronics employing a, then state of the art, Wein bridge circuit which is responsible for delivering the correct voltages to each of the two motor windings evenly. Needless to
say, late 60's - early 70's electronics in audio gear can always use some TLC, components refresh and definitely some periodic tune ups. The trimmers on the TD-125 PCB tend to grow touchy and lose
their settings and adjusting the speed control circuit, as per the service manual, is probably a must. With that said, the turntable performs best with an original and good condition belt, just like the TD-160.
It is a well respected, true hi-fi, highly capable, excellent performer turntable. The 125 can easily outperform any of the stock TD-16X series turntables. It was also a lot more expensive at it's time.
 
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