I am resto-mod'ing an early 1960s console stereo including using speakers capable of more bass output (and lower) and a 70s vintage TT with magnetic cartridge. One of my concerns is isolating or damping vibration to both the turntable and the vacuum tube phono preamp that I will be building for it.
My question is what is the best (reasonable cost) way to accomplish this? Spring mounting the TT and preamp chassis or perhaps an oil filled suspension platform. Would just a slab of granite (I happen to have one) to set the TT on provide good damping of vibration or would it just pass right through?
Any recommendations appreciated.
My question is what is the best (reasonable cost) way to accomplish this? Spring mounting the TT and preamp chassis or perhaps an oil filled suspension platform. Would just a slab of granite (I happen to have one) to set the TT on provide good damping of vibration or would it just pass right through?
Any recommendations appreciated.
Hi, using newer and powerful ( bassier ) speakers would put the whole structure under stress. Most things are to avoid nowadays, and one should be not house two speakers in the same chassis/enclosure. They are recessed from the baffle, have horrendous grill/cloth on the front and...it's one body!
Really, speakers should be separate.
Once you understand this, you can go on with your search for killing the vibrations, which of course would be much minor than if used in an all-in-one console but not less harmful.
Really, speakers should be separate.
Once you understand this, you can go on with your search for killing the vibrations, which of course would be much minor than if used in an all-in-one console but not less harmful.
Avoid spikes, springs, rubber but try a triple ball-and-cup arrangement and perhaps an air cushion underneath.
For the ball-and-cup, you need 3 concave shallow and smooth surfaces, as well as three hard smooth balls whose upper side will go above the rim of the concave surface.
On this should rest a smooth, hard, non resonant platform. This is either an extra slab that you install between your equipment and the balls, or else the bottom of your equipment if at all possible.
This will provide seismic isolation for low-level disturbances (and perhaps some measure of isolation vs air-driven vibrations), which are very detrimental to SQ.
For this project I want to stick closely to the original concept. The original speakers were good to 60Hz the new ones to maybe 40Hz or so. The really deep bass will still need to be handled by an external sub.
I plan to reinforce the console with internal bracing and the new drivers will be mounted from the outside and appropriate grills built to cover them.
I plan to reinforce the console with internal bracing and the new drivers will be mounted from the outside and appropriate grills built to cover them.
The other hole is where the original tweeter was. If there is enough room in front of the preamp and tuner chassis I plan to cover those holes and mount the Mark Audio 4" full range drivers a bit further outboard for better stereo separation. The woofs are Dayton (Parts Express) 8" DVC sub-woofers. I am going to try to incorporate small aperiodic enclosures for the woofs but even open back they are doing reasonably well. The crossover I have put together is 2nd order on the woofers and first order on the full ranges at 100Hz. The FR is already starting its natural roll off at that point so they should integrate pretty well that way.
The original console had a SE Pentode mode (no GNF) and rudimentary preamp on the amp chassis. I plan to convert that to a better preamp with active Bax tone controls and use a SE UL KT-88 PA that I built along with it to provide the electro-motive force. 🙂
I am in the process of running the simulations on the intended phono preamp (two stage passive EQ with cascode input stage, CC triode second VAS, and CF output buffer. I removed the original ceramic cartridge equipped TT and plan to set a 70s vintage LAB-440 TT with Shure magnetic cartridge in its place using the isolation we discussed here.
To brace all the panels of the cabinet I was planning to sandwich some pressed rubber (parts is parts) matting in between the existing panels and some 1/8-1/4" panels inside with battens and braces glued and screwed. The simple Masonite grill panels will be replaced with 1/2" or 3/4" thick MDF or OSB panels secured via screws from behind.
If the vibration can not be tamed enough for the TT and phono preamp to be in the cabinet I will just set it up for line level sources and put the TT and pre elsewhere and patch it in.
May seem like a lot of fuss for a little cheapo console but I think it will make a nice little apartment bomb. 🙂
mike
The original console had a SE Pentode mode (no GNF) and rudimentary preamp on the amp chassis. I plan to convert that to a better preamp with active Bax tone controls and use a SE UL KT-88 PA that I built along with it to provide the electro-motive force. 🙂
I am in the process of running the simulations on the intended phono preamp (two stage passive EQ with cascode input stage, CC triode second VAS, and CF output buffer. I removed the original ceramic cartridge equipped TT and plan to set a 70s vintage LAB-440 TT with Shure magnetic cartridge in its place using the isolation we discussed here.
To brace all the panels of the cabinet I was planning to sandwich some pressed rubber (parts is parts) matting in between the existing panels and some 1/8-1/4" panels inside with battens and braces glued and screwed. The simple Masonite grill panels will be replaced with 1/2" or 3/4" thick MDF or OSB panels secured via screws from behind.
If the vibration can not be tamed enough for the TT and phono preamp to be in the cabinet I will just set it up for line level sources and put the TT and pre elsewhere and patch it in.
May seem like a lot of fuss for a little cheapo console but I think it will make a nice little apartment bomb. 🙂
mike
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Sorry but I can't really think of it. For me it's a nonsense. There are some basic design guidelines that I follow and one is to keep everything separated in order to minimize the damage that may happen ( and Murphy's Law never fails...).
It the same principle that dictates that the motor of a TT should stay separated from the plinth, with only the rubber of the transmission being the mechanical joint.
🙄
It the same principle that dictates that the motor of a TT should stay separated from the plinth, with only the rubber of the transmission being the mechanical joint.
Well, springs made of rubber tensioned to a point is the key of a seismic base
🙄
I would not try to put a decent speaker in the same box as a decent turntable. Cheap low performance ones, as used in radiograms, are OK to share a box because the speakers don't go very low and the turntable suspension will be stiff and use a heavy tracking weight - and people don't expect good performance, just a 'nice sound'.
As I say, if the TT in the cabinet doesn't work I am prepared to set it up with an external table.
mount these beasts over a thick Styrofoam based foams, these materials can absorb vibrations and damp other noises.
Could you please post the image of the whole system.
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