Springs Under My Speakers: What's Happening?

[Phantomuser]

Those HK T-xxx series all had very springy feet in the first place. The T-65c was a pretty cool unit with a single point bearing, ITO arm and a quartz locked BSL motor driving belt to the platter. I have one here for parts actually, I was about to strip it. Fully restored a HK T-xx for Dad last year after he felt sorry for it when I said it was going to be scrapped.

The feet I removed from it were the originals and they were not springy at all ..just regular rigid plastic screw on feet.
The spring feet work a treat on it!
Btw does your HK have it's original rubber mat ? Ive been looking for one

 

[restorer-john]

The rubber spring cover/ dampers on my PL L1000 T/T were crumbly/perished with age.

I found these replicas as the originals are unobtanium in NOS condition - click on thumbnails.

View attachment 113297

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The seller makes small batches as the mood takes him and puts them up on Etsy. They sell out almost immediately.

https://www.etsy.com/au/listing/266683207/pioneer-peb-102-replacement-pl-630-pl

Details: https://www.etsy.com/au/listing/266...how_sold_out_detail=1&ref=nla_listing_details

When I was looking he only shipped to the U.S. from Etsy(no exceptions).

Occasionally he put some up on Ebay with international shipping. After a few misses I snagged a set.

Sorry for the diversion but it may help some vintage Pioneer T/T 'tragics'.

@restorer-john it may be worth your while checking the condition of your original spares. They may look fine but could disintegrate to the touch.

Yes, I threw out all the rotted rubber over the years. There's a number of good ones left, last time I looked in the container.

 

[restorer-john]

The feet I removed from it were the originals and they were not springy at all ..just regular rigid plastic screw on feet.
The spring feet work a treat on it!
Btw does your HK have it's original rubber mat ? Ive been looking for one

You are right, the T-65c has threaded rigid feet and relies on the suspended subchassis. The models below have a rigid subchassis and springy feet. I couldn't stand the bounciness of the model I restored recently for Dad, but he loved the sound of it and the isolation. It was on his desk for many months along with a couple of other TTs and an amplifier for headphone listening in his "office system".

Good question on the mat. I think I gave my Dad the mat and the heavy central record weight with the strobe markings on it. I'll check the box out.

Edit. Yes, I gave him the rubber mat, headshell and the record weight for the other HK I restored for him. Just checked my mat stash.

The T-65c is just a parts donor now (I think I've lost the platter somewhere in the storeroom too), it has an issue with the main bearing brass collar to the steel plate. There is movement with the platter on. Not the bearing but the swaging? to the steel mounting plate. I remember writing it off years ago as a viable restoration, but I never stripped it. I recently found out the bearing was the same as the lower models and I could have robbed the turntable I ultimately restored for Dad! Can't take it back now

 

[Phantomuser]

Incorrect . The HK T60 has the suspended sub chassis too.

 

[restorer-john]

Incorrect . The HK T60 has the suspended sub chassis too.

That's what I meant. Your T-60 chassis is likely identical underneath. The T-60 was TOTL 1983, the T-65c was TOTL 1984/5. Just an update. A bit like the PM-620/640/650/660 became the PM-645/655/665 etc the next year.

Incidentally, I have the original full range catalogues from those years if you are interested. I can scan them when I retrieve them from Dad's clutches..

Several pages on the Citation XX and XXP...

 

[Wombat]

Yes, I threw out all the rotted rubber over the years. There's a number of good ones left, last time I looked in the container.

That's good,

I don't know if the 'rubber' rots through endogenous reaction or exogenous reaction to air/pollutants. If the latter there may be a sealer that can be applied as a preventive. Any Chemists, here?

 

[restorer-john]

That's good,

I don't know if the 'rubber' rots through endogenous reaction or exogenous reaction to air/pollutants. If the latter there may be a sealer that can be applied as a preventive. Any Chemists, here?

OK, I had to check didn't I?

Here's the general "foot" stash from stripped turntables. You name it, there's some there. Complete sets and odd ones.

And the Pioneer foot container. There's 7 good boots and 1 marginal one, along with a many pillar/spring sets.

45 rpm adaptors

Counterweights

And you don't want to see the DD motors, BD motors, control PCBs, arms and mechs...

 

[restorer-john]

I don't know if the 'rubber' rots through endogenous reaction or exogenous reaction to air/pollutants.

All I know is rubber "rot" is completely unpredictable. I can have a bag of belts and one will rot, infect another or the whole lot. Sometimes one belt will turn to "goo" and its three identical twins will not- side by side in the same bag.

 

[puppet]

I've used pieces of these under "heavy" (altec valencia sized) enclosures between the cab and stand. Quick and dirty comparo between with and without ... Without, wood floor (platform frame) vibrations you could feel. With, no more vibration transferred to the floor. Cut off the hooks and use the flat section.

 

[ROOSKIE]

I like this design.

https://www.mesanovicmicrophones.com/iso-platform

 

[Purité Audio]

I will measure my RT`m10’s with and without their isolation platform, I have an engineered floor here, layer over floorboards with some ‘acoustic’ membrane in between.
Keith

 

[MattHooper]

Apropos of the question asked in my OP, this is an interesting video.

It's a video from the swiss speaker manufacturer Credo, explaining the effects of isolation vs a speaker sitting on a floor or spiked, demonstrated with measurements.

It includes measurements of a Townshend isolation platform along with their own platform measurements. It seems to map quite well to the effects I heard in my room:

 

[pjug]

I really don't get why the difference can't be measured with a microphone if these are significant. It seems obvious that differences in floor and cabinet vibrations would be found, but are these enough to make any real difference in what is heard? I am looking forward to what @Purité Audio finds.

 

[MattHooper]

I really don't get why the difference can't be measured with a microphone if these are significant. It seems obvious that differences in vibrations would be found, but are these enough to make any real difference in what is heard? I am looking forward to what @Purité Audio finds.

If you watch the video I just posted, towards the end they do indeed measure how the sound changes in room using a microphone at the listening position. That starts at 11:15 in the video.

 

[pjug]

Ah, thanks. I didn't make it that far. Interesting and convincing.

 

[MattHooper]

Ah, thanks. I didn't make it that far. Interesting and convincing.

Agreed.

I liked how it showed the frequency response remaining the same, just reducing additive distortion/ringing energy.

That's just what things sound like with my speakers on the springs. Same frequency balance and tone, but everything just more focused and cleared up tonally and spatially. Like seeing the same scene but with a better glasses prescription.

 

[ernestcarl]

If you watch the video I just posted, towards the end they do indeed measure how the sound changes in room using a microphone at the listening position. That starts at 11:15 in the video.

There is a small difference. Eh... which I kind of expected. Just nothing significant enough for me to be wow’d into running of and buying...

 

[Deleted member 65]

This is what I use, works well.

http://www.soundcare.no/measurement.htm

 

[BluesDaddy]

I remember way way back, trying the suspended from the ceiling thing guys were talking up in the mid 70s. A nightmare!
I can't remember what I used for a spring holding the deal up, and a large planter basket with a piece of 3/4 plywood in the bottom
a little bigger then the size of my AR-XB table. Getting records on and off the thing without setting the basket to swinging all around or bouncing up and down was a terrible chore. Needed some trick dampening but I never could figure out what to do. After about 2 months it all went in
the garbage except for the AR table. LOL
We've gone thru some crazy stuff trying to get those LP's to play decent.

I briefly tried this in or around 1980 while living in a "pre-manufactured home" where any footsteps caused my turntable to skip like crazy - and I had a fully manual one. Yes, it was a nightmare.

 

[MattHooper]

There is a small difference. Eh... which I kind of expected. Just nothing significant enough for me to be wow’d into running of and buying...

This could be one of those cases were simply looking at measurements or a graph isn't a good substitute for hearing it yourself, where what look like subtle differences on a graph have a larger subjective impact. (After all, subtle-looking differences in an upper frequency response in a speaker measurements can translate in to someone finding a speaker "too bright" to enjoy, vs another slightly flatter response).

In my case, presuming the spring footers I'm using are causing a similar type of improvement, I'd probably look at those graphs and think "eh...kind of interesting I guess." But when I actually hear what it does for the sound, like I just truly upgraded to better speakers, it's extremely significant and worth doing.