JacquesB's first LENCO prototype

[JacquesB]

since two days, I have added to my system MY FIRST PTP4B BASED LENCO PROTOTYPE !  It is fitted with the old Goldmund T3F linear tracking arm, and a DENON DL103 cartridge. The first listening results are stunning, and I can say that , at that point of preliminary development, it sounds already at least as good as the Goldmund Ref TT, particularly in terms of bass firmness and definition, overall soundstage stability and precision…. more to come later

The plinth is made of 5 layers of 19 mm thick medium

I am now using the experience I have acquired to make this prototype, to design a new prototype which will be entirely made from a block of aluminium, machined with  precision .

I hope to be able to show you soon the first photographs of the aluminium block (around 130 pounds)

[hatehifi]

Jacques, I think you got the Lenco bite...  I don't miss 'other' TTs anymore either. Glad you are having fun! That is, IMHO what music appreciation is about.

Cheers!
John

[bluemike]

Jaques thanks for sharing these pictures with us - they are spelidid !

I'm interested on getting your take on how your LENCO prototype differs from your regular table in terms of overall musical enjoyment 

[JacquesB]

Hello !

sorry for this delay

I reported elsewhere on the site some kind of comparison between my regular TT, a 20 years old Goldmund Reference Turntable (GRTT), and my first PTP based Lenco prototype. But perhaps this thread is a better one for this comparison:


Comparison between Goldmund Reference TT  and PTP based LENCO PROTOTYPE:

First, I have to mention that the Goldmund  (GRTT)is now, after more than 10 years in my hands, at its best condition. I have used a new oil for the bearing, which is a personal creation, and which has impressively improved the qualities of the original GRTT.  Then , three years ago, I had big troubles with the motor power supply, which has not yet been solved , and I found an alternative solution with the Verus motor system from Teres Audio. This system drives directly the platter through its outer edge, like an idler wheel would do, and gives me  great satisfaction. I can say that the GRTT fitted this way sounds even better that the original one. You must know that, for economical purpose, the original motor used in the GRTT is not the best that could have been choosed at that time thirty years ago. This is a general problem in industrial gear, the price of the separate elements must stay below 1/5 of the final retail price, for the business to remain possible. For this reason, even great quality gear like Jadis for example , can be easily improved by replacing the cheap components by better ones.

the other important element of the GRTT to be replaced was the T3F Linear tracking arm. This arm has great qualities, but his conception was made with the technology  and the knowledge that were available 30 years ago.  The main negative points of this arm are:
-lack of rigidity of the mechanical parts, and especially the bearings, which are too loose;
-enormous difficulties to adjust the tracking force, due to counterweight conception
-difficulties, which can be overcome ,to adjust azimuth

After reading lots of reviews, I finally choosed the KUZMA 4 POINT  tone arm. After designing and machining of a proper aluminium board to adapt this arm to the GRTT chassis, I must say that I do not regret my choice: this tone arm is the most seriously constructed that i have ever had in my hands. all adjustments can be made easily with great precision and reproducibility, even delicate adjustments like azimuth or antiskating . The VTA can be adjusted while the the TT is running, which is very important.

The result was stunning, with the same Clearaudio Stradivari cartridge that I was already using on the GRTT since a few months:
The general tonal equilibrium seemed immediately better, with firm bass, and delicate treble, without any agressivity. The sound stage gained in stability, in a tridimensional impressive way. The focusing of all instruments or singers was greatly improved . For example, the choirs in the "Cantate Domino" LP , let distinguish clearly all the individual voices, which was not the case before.

Then, I moved to my first PTP based LENCO prototype, which , as you see on the photographs, is made with a very ordinary medium plinth, on which I mounted the T3F linear tracking arm fitted with an old DENON DL 103 cartridge. The only particular features are:
-my special oil for the original Lenco bearing
-a special design for the treatment of bearing and tonearm vibrations, which uses a very simple steel rod  pressed against PTP4 and T3F armboard, through the plinth, and transmits directly all parasite vibrations to the concrete floor.

The result is stunning. There is not much difference that can be heard between the two TTs !
I am making constant comparisons every day since a couple of weeks , between the two TTs. What I can say is that all the qualities that I loved in my GRTT, have been fully found in the Lenco !  Perhaps, the GRTT, with its better tonearm and cartridge, goes a little bit further in soundstage precision and precise focusing, with slightly better tonal equilibrium.  But the lenco  shows  clearly better bass, and an overall credibility and stability to the soundstage.

At the present stage of development, I am clearly unable to choose between these two TTs ! So does my wife too !

I am now working on a new design for the lenco, based on a plinth which will be machined in a 120 pounds aluminium block...and fitted with the kuzma tonarm ...

[ropie]

The result is stunning. There is not much difference that can be heard between the two TTs !
I am making constant comparisons every day since a couple of weeks , between the two TTs. What I can say is that all the qualities that I loved in my GRTT, have been fully found in the Lenco !  Perhaps, the GRTT, with its better tonearm and cartridge, goes a little bit further in soundstage precision and precise focusing, with slightly better tonal equilibrium.  But the lenco  shows  clearly better bass, and an overall credibility and stability to the soundstage.

Hi Jacques,

Thanks for posting a detailed write up of your existing tt.  Although I'm not surprised by your findings (having heard similar stories from many experienced ex-hi-end turntable users here) I am pleased you've had such good results!  I do like the visuals of your T3F linear arm but it does look like it could also be a bit of a trial to set up.   Does it work on a similar principal to the Revox linear arms?

[JacquesB]

The T3F tone arm is not so difficult to set up

The principle is the following:
the tonearm and the sensor arm are both suspended to a mobile chassis which is moved by a  step by step motor, through belt and two pulleys. The tone arm has a certain degree of liberty in the lateral plan, and can  follow the groove. As soon as the sensor arm detects an angle of more than one degree between the tone arm and himself, by means of an electro-optical system, it commands the motor which moves the mobile chassis forward.

The main difficulty in the set up of this arm , is the adjustment of the tracking force : due to inappropriate conception, the counterweight is blocked by an Allen screw. Once you have determined the good position of the counterweight by means of a balance, you try to tighten the Allen screw, and this is almost impossible to perform without moving the counterweight !  so you can spend up to one or two hours to adjust tracking force !

[rfgumby]

  I have a friend who I think has the same Goldmund Reference turntable (I haven't been to his place in a while).  Great sounding unit, smooth yet powerful.  Kind of a different beast, though, but the lighter arm probably balances the calm dark and quietness of the table.    Isn't that the arm with the little laser mirror behind the head shell to run the linear arm drive motor?   Regardless, that is a cool table.

  Nice to hear about your positive impressions so far with the Lenco project.  Already kind of fun too, no?  Lencos have probably been the largest influence of playing music and having fun in audio I've done in a long time, maybe ever.  A useful pleasant forum doesn't hurt either.   

Please keep us informed, I already love reading your posts, they're informative and interesting. 

[hatehifi]

Hi Jacques,

I am interested in how you 'earthed' the PTP4 and arm board. Any photograph?

I've heard good things about the KUZMA 4 Point but never actually auditioned. Have you had only the Goldmund arm in your system till now?

Cheers!

[gut_man]

Nice table, and an interresting comparison of the Goldmund and the Lenco. I can vouch for the Kuzma 4 point and the match with a Lenco PTP. One other thing to take into consideration is an upgrade of the bearing. I understand you use the original Lenco bearing. I use Jeremys Legend myself, and am stunned with the results!