Vintage DD turntables. Are we living dangerously?

Hi Halcro,

On another thread you indicated that you've transitioned from a metal skeleton metal frame plinth to a solid Granite plinth for your TT-101. From the picture, I didn't see holes in the circular Granite to accomadate hardware for securing the TT-101. Is the TT-101 resting on the Granite without being fasten to the Granite?  Would you please describe what are the sonic differences? Thank you

Norm

Hi Halcro,

I should begin by saying, “nice job on the granite plinth”, which I neglected to mention on my earlier post. The black granite matches the armpods beautifully.

Thank you for the in-depth explanation to my inquiries.  The reason for my curiosity is because I’ve recently joined an exclusive” Are we living dangerously?” club. My JVC/Victor TT-101 was sold to me with a CL-P2 plinth and acrylic dust cover.  The Victor CL-P2 plinth is made from particle board with a veneer clad, faux Rosewood, as with most plinths made from this era. The plinth itself is quite heavy and comes with four large plastic footers.  The TT motor is evenly secured with hardware to the wood plinth.  I’m looking for ways to improve on this plinth; whether it is a custom plinth as you have done or tweak the existing CL-P2.  An Elgar 6000A line conditioner is used to feed 100VAC to the TT-101. I’ve dialed down the Elgar to the lowest possible voltage of 105VAC to best meet TT-101 requirements. I need to shuffle my equipment around to accommodate the TT-101 before spinning any vinyl on this TT.

Since my inquiry on how your custom granite plinth is coupled to the TT-101 motor, several posters have commented to your approach.  To me, it seems intuitive to mechanically fasten the motor to the plinth for best sonic results. What was the rationale to have the motor “sit” on the rubber points rather than have it bolted in place? I noticed the metal skeleton plinth also used rubber supports.  Did you experiment both ways before concluding that this was sonically the best approach? It seems intrinsic that the plinth material selected has a lesser degree of importance when the motor just “sit” on the plinth as opposed to mechanically coupling the motor to the plinth.    

Furthermore, is it possible the granite plinth sounds better than the open metal skeleton design because the granite design encases the TT and is able to shield air borne vibrations reaching the motor?

Regards,

Norm 

Hi Halco,

My primary TT is the Scheu Premier with Verus Rim Drive and Talea II tonearm sitting on a Minus K.  I also have a Technics SP-10 Mk2a in a DIY plinth and EPA-100 arm.  I will audition the TT-101 with a SAEC WE-506-30 arm.  Eventually, all three tonearms will be heard with the TT-101. My end goal is to have multiple tonearms on one TT.  

 I have put the JVC TT-101 through its paces and verified everything works as it should. The KAB Speedstrobe confirms its speed stability as well.

Thanks for sharing your thoughts on the JVC wood plinth and its short comings.

You will agree I have a tedious task ahead of me to determine if the TT-101 truly merits a place on the Minus K.

To all Victor TT-101 owners:

I’m hearing a “hum” when I press my ear up to the platter mat. Sounds like a transformer hum.  Doubt very much this is normal. Would other JVC DD table owners please chime in and comment on this?

All the electronics are original. Will replacing the caps in the PS board eliminate this hum? Or is it something more seriously wrong? Like a bad/noisy transformer? The wall voltage measures between 102-103VAC.

Plans to replace all the electrolytic caps are in the works.

I’ve also noticed on several occasions the speed briefly jumps from “33.33” to “33.32 or 33.34” during lp playing. Is this normal? Playing one side of an lp, this may occur once or twice, or no at all.  

Halcro, is this what you mean by “Are we living Dangerously”?

Hi Lewm,

Yes, the platter is stationary where the constant hum is travelled up to the platter mat.

I'm in Canada where 117v is standard. I'm using an Elgar 600A power conditioner adjusted to the unit's minimal output voltage setting of 103VAC. 

There is a diagram on the TT-101 transformer depicting 100vac as primary and 2 x 16.5vac / 1.2a, and 10.0vac / 1.0a as secondaries. 

I've replaced all the capacitors (8 in total) on the PS board in hopes of curing the hum. No luck. However, the speed fluctuation that I was experiencing earlier seem to have disappeared with the new caps.  

Following other TOTL DD designs, I've decided to move the xfmr into an external chassis.  I'll post my results when this is done.   

Dear PJ & Lewm,

A step-down voltage transformer is on order. 

Thank-you

Norm

Tried a new step-down transformer. It is now 98% hum free. A BIG improvement over the Elgar. Which confirms I have a broken Elgar. With ear pressed against the platter mat, I am still able to detect a difference between on/off.

Would other TT-101 owners check this with their units if they can detect any difference between on and off?

Thank you.     

Hi Peter,

Sorry for the late response. I like to resolve my hum noise first before deciding on a USA made step-down transformer. I will reach out to JP at a later date to see if he can help. Thanks for asking.

Norm 

Hi Halco,

Sorry to hear about the TT-101. Hope your Tech can return the TT-101 back to its original glory. We can only make assumptions why the TT-81 sound better than the TT-101.  Could it be possible that the TT-101 performance deteriorated overtime and went unnoticed?  Your redundancy in power surge protection should have kept the TT-101 from harm.  Is it possible the power outage was merely a coincidence the TT-101 failed? It’s difficult to imagine two models made by the same company where their “top” model is trumped by a lower model. When the TT-101 is back on-line, you will undoubtedly do another side by side comparison again.  That should settle the ambiguity