Whoa Reuben, Congratulations; lucky you. Sorry for the noob question but where is the tonearm and cartridge?
My Lenco L75 Master Turntable Build
- Thread starter reubensm
- Start date
hildebrand
Active Member
Congratulations. Great News! Very happy for you!!
reignofchaos
Well-Known Member
Wow! Pretty amazing - the table is in spectacular condition. What arm and cartridge are you planning to add to the table? The plinth build will also be crucial.
reubensm
Well-Known Member
Thanks RP, you're the man.
Yes I was fully aware that this was an early Garrard with the Flat Strobe. I read on the internet that these are very desirable but did not actually set out to accquire one. Came across this one by chance and did'nt waste a second to decide.
Change of plans, skipping the Thorens idea for now. Lenco on the back seat, may use it ultimately as my second deck. I am planning to set up a home-office for which I will need it.
reubensm
Well-Known Member
Thanks Captain, always great to hear from you. Not decided yet but I have the Jelco with me, will probably make a start with it.
reubensm
Well-Known Member
Yes, the plinth build will be crital and I will be reaching out to Mr. Kuruvila to guide me on that aspect. With regard to the tonearm, for now I will be using my Jelco Tonearm, will move to a better one after listening to it. I've always been a Shure cart guy so will have to give this aspect some thought.
reubensm
Well-Known Member
Yes, this deck was owned from the day it was purchased new, by the same audiophile owner. He had 2 decks and as he is in advanced age, he wanted to let one go to free up some money, for supplementing his medical expenses. Both were in absolutely pristine condition (purchased new and single owership, with no break-down or mod history). I decided on this one as this was the rare (and extremely desirable) flat strobe model. Also as it is an older 401 model, it could be as close to the 301 (atleast from a period perspective), that I can get to, at the moment.
Apart from getting the deck, I was extremely happy to be of some help to the old gentleman.
Congratulations Reuben. The player looks in real mint condition. Amazing acquisition. And truly, its raining 401s on our forum. The TT Gods must be happy and are showing their grace on our forum members and helping them acquire what they have been looking for long.
When is Sir Garrard coming home?
When is Sir Garrard coming home?
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Gerry_the_Merry
Well-Known Member
Quite an awesome looking deck, Reuben.
shafic
Well-Known Member
Sir Reuben!! Congrats!!
The deck looks awesome. Helping people is a great feeling. BTW how come there is no plinth and arm?
The deck looks awesome. Helping people is a great feeling. BTW how come there is no plinth and arm?
reubensm
Well-Known Member
Yes indeed, on another note Saket, people like myself have a lot of experience with good turntables like Technics Direct drives and can talk for hours about them. However at the end of the day, these TTs are not in the same league as the big ones and we've never played in the big league. Shafic, Record Player and my accquisition of the 401 is great for the forum as we too can add to the already knowledgeable crowd on the Thorens', EMTs, Garrards and Sondeks.
On another note, the 401 also realizes my dad's dream. He always wanted to get one of the big Garrards but being a Central Govt. Engineer, he could afford only a TT like the Garrard SP25 (which he bought during one of his foreign visits back in the 70s). Unfortunately he is not around to see Sir Garrard make his entry.
My colleague's assignments gets done by the last week of March so Sir Garrard will arrive with him. If he gets done earlier, then Sir Garrard will make an early arrival.
reubensm
Well-Known Member
The gentleman who owned it had a single plinth and SME3009 and used to switch between 2 401 decks, using the same plinth and tonearm. He was gracious enough to let me choose which deck I wanted and I opted for this one. It would have been difficult for my colleague to carry the plinth anyways, so in a way, getting the deck without the plinth was a blessing in disguise.
reignofchaos
Well-Known Member
Actually not having an arm and plinth is really good. You can build the perfect plinth to your specs and purchase a really good arm based on personal choice. A jelco is a good first choice.
However that turntable deserves a lot lot better - a schroder/sme 3012/graham/scheu/thomas schick would be ideal based on personal tastes.
However that turntable deserves a lot lot better - a schroder/sme 3012/graham/scheu/thomas schick would be ideal based on personal tastes.
Exactly. These turntables are the real men. That is why I am looking forward to quick arrival of the 401 in your stable. I will be waiting impatiently to read your review of the 401. That is surely going to be insightful - as it will be coming from you. Also, eagerly waiting for 'Sir' RP to put his views too on the 401.
Good on you Reuben to think like that. Even I miss my dad when I think of how nice it would have been if he was around. I am sure, he would have enjoyed even my humble Technics DD more than myself. He probably loved vinyls more than I do and bought whatever he could afford at that time in the early 70s, and he is solely responsible for developing my love towards the medium. I remember the first day when he took out his HMV Fiesta from storage and gave it a spin for me when I was 6-7 years old. Thankfully, I did not do any damage to his vinyl records and the player even as a child and in fact cared for it so much that the player still sings immaculately with some good speed accuracy. Though, as you would recall, it has gone some electronic changes under its hood, but cosmetically, it's untouched.
Regards,
Saket
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shafic
Well-Known Member
Yes Reuben,it also gives you the freedom of choosing the plinth and tone arm as per your wish.
reubensm
Well-Known Member
musiklava79
Active Member
@ Cat's Squirrel
Your post gave us some deep insights into the factors that should be taken into consideration while constructing TT plinths. Thank you so much for your thoughts on the subject. I have a few questions to put to you - more so to clear certain doubts...
A. You have selected the Ironwood and Ironbark as your choices that qualify for plinth construction, but you have not stated the criterion for your choices. The damping quotients are not available for these varieties of timber in the link that you provided. In any case, after comparision with some varieties mentioned there, the damping quotient is likely to be low. Hence, I presume that hardness and/or density of the timber would be one of the factors because the average density of these timber varieties are about 1150 to 1260 kg/cu.mt. If that is so, would the following timber varieties meet the same criteria? Please note that these are India-specific timbers and hence are locally available, whereas the cost of the imported would be prohibitive indeed.
1. Mesua Ferrea - English names Ceylon Ironwood, Indian Rose Chestnut, Indian Ironwood. Local names Nagachampakam, Nahar. Found in South India and North-east India. Density - 940 - 1195 kg/cu.mt. Have you ever tried driving a nail into seasoned Ironwood? Try it once!!
2. Acacia Catechu Wild - English name Catechu. Local name Khair. Found in Southern and Western India. Density - 1050 kg/cu.mt average.
3. Tamarindus Indica - Tamarind Found all over India. Density - 1280 kg./cu.mt average.
4. The outer layer of the palm tree can also be considered as its density is about 1050 kg.cu.m.
There are many other varieties of hardwood available, depending on the local region.
B. When we discuss the need for damping a plinth, are we talking about damping mechanical vibrations or resonance? Which requires more attention the former or the latter? I think thats because each individual moving component of a TT has its own frequency and hence, resonance and mechanical vibration!
C. My other question concerns CLD. This concept has found application in a variety of other fields like construction, Industry and so on. If you state that if some form of CLD be applied to TT plinths, then it would be in the form of a sandwich construction where the wooden plinth would be divided into two (or more) parts and some sort of visco-elastic substance be inserted between the harder layers (the wooden parts). When you mention plinth thickness I presume that you mean the height of the plinth. But let us not forget that the plinth wall (plinth height) also has thickness. Except for stock factory releases which have uniform thickness, all DIY designs have varying thicknesses, that is, after leaving out the portion that has been cut out of the plinth block. Doesnt this thickness also have a role to play in the mechanical vibrations or resonance? I hope I have been able to convey my doubts clearly and Id like to hear your opinion on this.
My queries also refer to your comments in Mr.Kuruvilla' thread.
Your post gave us some deep insights into the factors that should be taken into consideration while constructing TT plinths. Thank you so much for your thoughts on the subject. I have a few questions to put to you - more so to clear certain doubts...
A. You have selected the Ironwood and Ironbark as your choices that qualify for plinth construction, but you have not stated the criterion for your choices. The damping quotients are not available for these varieties of timber in the link that you provided. In any case, after comparision with some varieties mentioned there, the damping quotient is likely to be low. Hence, I presume that hardness and/or density of the timber would be one of the factors because the average density of these timber varieties are about 1150 to 1260 kg/cu.mt. If that is so, would the following timber varieties meet the same criteria? Please note that these are India-specific timbers and hence are locally available, whereas the cost of the imported would be prohibitive indeed.
1. Mesua Ferrea - English names Ceylon Ironwood, Indian Rose Chestnut, Indian Ironwood. Local names Nagachampakam, Nahar. Found in South India and North-east India. Density - 940 - 1195 kg/cu.mt. Have you ever tried driving a nail into seasoned Ironwood? Try it once!!
2. Acacia Catechu Wild - English name Catechu. Local name Khair. Found in Southern and Western India. Density - 1050 kg/cu.mt average.
3. Tamarindus Indica - Tamarind Found all over India. Density - 1280 kg./cu.mt average.
4. The outer layer of the palm tree can also be considered as its density is about 1050 kg.cu.m.
There are many other varieties of hardwood available, depending on the local region.
B. When we discuss the need for damping a plinth, are we talking about damping mechanical vibrations or resonance? Which requires more attention the former or the latter? I think thats because each individual moving component of a TT has its own frequency and hence, resonance and mechanical vibration!
C. My other question concerns CLD. This concept has found application in a variety of other fields like construction, Industry and so on. If you state that if some form of CLD be applied to TT plinths, then it would be in the form of a sandwich construction where the wooden plinth would be divided into two (or more) parts and some sort of visco-elastic substance be inserted between the harder layers (the wooden parts). When you mention plinth thickness I presume that you mean the height of the plinth. But let us not forget that the plinth wall (plinth height) also has thickness. Except for stock factory releases which have uniform thickness, all DIY designs have varying thicknesses, that is, after leaving out the portion that has been cut out of the plinth block. Doesnt this thickness also have a role to play in the mechanical vibrations or resonance? I hope I have been able to convey my doubts clearly and Id like to hear your opinion on this.
My queries also refer to your comments in Mr.Kuruvilla' thread.
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cat's squirrel
New Member
when choosing a material for plinth duty, there are three main parameters to consider, stiffness, mass and damping. Of these three, damping is the most important, as it is the hardest criterion to satisfy (enough damping!) but also it has effects right across the audio spectrum (and above!). So choosing a material starts by looking at that material's damping factor. A damping factor of 0.4 or above is the target to aim for, but 0.4 is good enough for our purposes. Stiffness values are considered, more from a structural point of view, and more stiffness can be added using thin metal plate, for example.
Mass is a product of size and density, but a low density, stiff and highly damping material would make a suitable plinth, as much as a high mass equivalent. And don't underestimate the importance of the thickness of the material. Thickness means the vertical component if a panel is laid flat on the ground. So density, per se, is not important.
The damping factor values for the woods I recommend are here:
best natural wood yet : new topics on this forum
One cannot guess (or calculate) the damping factor value (I've tried to guess, and I am usually wrong! ), the only way is to test it. If you want it tested (for free) you will have to send me a piece, 100mm x 100mm x about 20mm.
As regards vibrations and resonances, these terms are often confused, and used interchangeably, incorrectly. When it comes to plinths, we could have vibrations, some of which may be resonances. A resonance is a natural vibration where maximum amplitude is reached with a minimum of energy input. Pick up an object, and hit it, it will usually make a sound, these are the resonances. However, we could have a vibration source (like a motor) and place it on a panel of wood, and sense the vibrations in the wood. These are vibrations, and not resonances. Only if the forcing vibrations from the motor were at the same frequency as the natural resonance frequency of the wood would we have resonances, (and a big problem)!
The plinth is there to support the turntable mechanicals, but more importantly (in my opinion) to reduce the amplitude of vibrations from the turntable, floor and air which could vibrate the whole system. To reduce the amplitude of the vibrations from the turntable, it must be connected to the chosen plinth material as well as possible, so-called 'coupled'. This is because the plinth vibrates (mostly) by moving up and down. The goal is to couple the turntable bits to the plinth material, so that they move up and down together. That way, the chosen material, if it has a good damping factor, will reduce the amplitude of the vibrations very quickly, so that they don't have time to build. This is where most plinths fail, the chosen material/s do not disperse the energy in the system fast enough, and the vibrational amplitudes build to unacceptable levels.
cld found its way into hifi by the term being misapplied, as mentioned. It has been used in the aircraft industry for a long time, where vibrating panels have been damped using this technique. It is most effective where the thing to be damped is a thin panel. I would not make a plinth by sandwiching a viscoelastic layer between two pieces of wood, in that case, it is wrong to support the lower layer while connecting the turntable to the upper layer, as the viscoelastic layer will de-couple the lower layer.
I have been considering plinths as a flat panel, but some plinths are more of a picture frame construction. In that case, each side can be thought of as a panel, where the thickness is considered the smallest dimension. The stock Lenco plinth is like this. In which case, each part of the frame can be considered for vibrational analysis, but that requires software called 'finite element analysis', which is expensive, and I don't have.
HTH
Mass is a product of size and density, but a low density, stiff and highly damping material would make a suitable plinth, as much as a high mass equivalent. And don't underestimate the importance of the thickness of the material. Thickness means the vertical component if a panel is laid flat on the ground. So density, per se, is not important.
The damping factor values for the woods I recommend are here:
best natural wood yet : new topics on this forum
One cannot guess (or calculate) the damping factor value (I've tried to guess, and I am usually wrong! ), the only way is to test it. If you want it tested (for free) you will have to send me a piece, 100mm x 100mm x about 20mm.
As regards vibrations and resonances, these terms are often confused, and used interchangeably, incorrectly. When it comes to plinths, we could have vibrations, some of which may be resonances. A resonance is a natural vibration where maximum amplitude is reached with a minimum of energy input. Pick up an object, and hit it, it will usually make a sound, these are the resonances. However, we could have a vibration source (like a motor) and place it on a panel of wood, and sense the vibrations in the wood. These are vibrations, and not resonances. Only if the forcing vibrations from the motor were at the same frequency as the natural resonance frequency of the wood would we have resonances, (and a big problem)!
The plinth is there to support the turntable mechanicals, but more importantly (in my opinion) to reduce the amplitude of vibrations from the turntable, floor and air which could vibrate the whole system. To reduce the amplitude of the vibrations from the turntable, it must be connected to the chosen plinth material as well as possible, so-called 'coupled'. This is because the plinth vibrates (mostly) by moving up and down. The goal is to couple the turntable bits to the plinth material, so that they move up and down together. That way, the chosen material, if it has a good damping factor, will reduce the amplitude of the vibrations very quickly, so that they don't have time to build. This is where most plinths fail, the chosen material/s do not disperse the energy in the system fast enough, and the vibrational amplitudes build to unacceptable levels.
cld found its way into hifi by the term being misapplied, as mentioned. It has been used in the aircraft industry for a long time, where vibrating panels have been damped using this technique. It is most effective where the thing to be damped is a thin panel. I would not make a plinth by sandwiching a viscoelastic layer between two pieces of wood, in that case, it is wrong to support the lower layer while connecting the turntable to the upper layer, as the viscoelastic layer will de-couple the lower layer.
I have been considering plinths as a flat panel, but some plinths are more of a picture frame construction. In that case, each side can be thought of as a panel, where the thickness is considered the smallest dimension. The stock Lenco plinth is like this. In which case, each part of the frame can be considered for vibrational analysis, but that requires software called 'finite element analysis', which is expensive, and I don't have.
HTH
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musiklava79
Active Member
Thanks, cat's squirrel, for that prompt reply. The Indian Ironwood is used for structural purposes such as posts, beams and railway sleepers (once upon a time). Carpenters generally hate them as the seasoned timber is very tough and can't be sawed or planed very easily! One can presume that some of the factors you mentioned must be inherent!
Thickness as a vertical component for you, not in my line!
However, I'll be happy to follow your line of thinking as far as plinth building is concerned....
I'll be glad if you can do it, please. If you will PM me your address, I'll try to send you a sample of the wood once I get hold of a carpenter who will be willing to cut this size for me. Mind you, the timber is over 50 years old. My power tools are too light for this kind of job! May I also send one or two other hardwood samples which are typical to our area, please?
If that be so, why not build plinths like the manufacturers do but with better materials and support, that is, braces and side panels, with one solid panel (Which is also suitable damped before being affixed to the braces) above to support the turntable brace plate with some damping material placed between the two solid surfaces? You've got a thin, hard and flat panel with the desired damping factor and some kind of a strip of a material like sorbothane or similar visco-elastic material placed between the two plates. Won't that be enough to reduce most of the unwanted vibrations and resonance and also achieve a simultaneous up and down movement of the components?
Would appreciate it if you can provide us with a sketch of your proposed plinth which I find, also gets mentioned in the link that you provided.
Thanks once again.
P.S. - There's another query addressed to you in the link below. I'll be glad to hear your opinion on this subject as well.
http://www.hifivision.com/phono-tur...chnics-sl1200mkii-tonearm-rewire-damping.html
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