| gurevise |
Guys,
I have old Linn Basik TT. It has DIN style connector at the bottom of the tonearm. I'd like to build a better phono cable between TT and phono stage. I have found a good Cardas DIN and RCA connectors.
I'm not sure about cable to use for this project. I need about 2...3 feet cable.
Can you guys recommend a good phono cable?
I would appreciate comments/suggestions about shielded/no-shielded cable type.
Thanks
Sergey |
|
|
| fdegrove |
Hi,
2-3 feet is too long for MCs.
What type of cartridge are you using?
Ciao,;) |
|
|
| gurevise |
I use Shure V15VxMR MM cartridge. It's output is about 3mv.
I would also very appreciate all suggestions/thoughts on cable length.
Thanks
Sergey |
|
|
| fdegrove |
Hi,
| quote: | | I would also very appreciate all suggestions/thoughts on cable length. |
As short as you can manage practically is about the best advise I can give.
If you can afford it and want sonic fireworks from the humble Shure cart, try silver solid core....They're absolutely stunning combined correctly.
Cheers,;) |
|
|
| gurevise |
Can you be more specific about solid core silver cable type, sources and construction.
I can get some silver cables from www.homegrownaudio.com
They have some UN shielded silver cables.
Sergey |
|
|
| fdegrove |
Hi,
| quote: | | Can you be more specific about solid core silver cable type, sources and construction. |
Your quoted source seems fine to me.
A simple twisted solid core silver wire should be fine.
Cheers, ;) |
|
|
| sreten |
TBH IMO it won't make much difference.
You can vary capacitance at the amplifier inputs quite easily.
Just being honest , I think you are wasting your time / effort.
The standard Linn lead for the LVX is perfectly adequate IMO.
Its much more basic than 'silver' conductors.
:) sreten. |
|
|
| fdegrove |
Hi,
| quote: | | Its much more basic than 'silver' conductors. |
And you've tried this out, no?
Guess not...
Cheers,;) |
|
|
| sreten |
| quote: | Originally posted by fdegrove
Hi,
And you've tried this out, no?
Guess not...
Cheers,;) |
Of course not in the terms you describe, there are far more
fundamental issues to attend to than exotic connections,
of these alternatives I've tried lots.
I've also tried cable alternatives but not the silver option
you describe. The above is far more important than cables.
I stand by my opinion.
:) sreten. |
|
|
| fdegrove |
Hi,
| quote: | Of course not in the terms you describe, there are far more fundamental issues to attend to than exotic connections,
of these alternatives I've tried lots. |
Such as?
And what if we have these fundamentals sorted out already?
Do you still feel I/Cs won't make a difference? Wouldn't silver cable be making a difference?
Yes, get the basics right first, then optimise the potential...
Cheers, ;) |
|
|
| sreten |
Well the Linn Basik turntable isn't exactly the last thing known
to rocket science, by design its intended to be a good turntable
but not remotely a stab at the ultimate.
Playing around with the leads has to be :
Compared to any sound engineering approach to addressing the
limitations of the turntable. If you do this you'll find that there is
not much you can actually do in ultimate performance.
You can do better, if you know what you are doing,
:) sreten. |
|
|
| fdegrove |
Hi,
| quote: | | Well the Linn Basik turntable isn't exactly the last thing known |
Agreed.
Yet, improving on the I/C between cart and TT is not going to hurt it either.
If anything, it's going to throw up the shortcomings of the Linn casseroles, isn't it?
Not a bad thing and you can still keep the I/C for the next TT upgrade, right?
Right. ;) |
|
|
| sreten |
I'm sorry but I'm not into over engineering and / or ********.
The worlds greatest interconnect should improve any turntable,
but its a facetious argument IMO only defended by the ignorant.
Much better to get a good turntable shelf mounting IMO,
bolt the support to a brick wall IMO, is the upgrade to make.
:) sreten. |
|
|
| fdegrove |
Hi,
| quote: | | The worlds greatest interconnect should improve any turntable, |
Pardon me, but, no...it won't improve that TT in any way.
Not if you mean the TT itself that is.
Cheers,;) |
|
|
| sreten |
hi frank,
is quoting only half a sentence fair ?
;) |
|
|
| fdegrove |
Hi,
| quote: | | is quoting only half a sentence fair ? |
That's a full quote for you...
Don't know, really. I suppose the world is dominated by Micro$ftware?
I could address that if it makes you any more happy....
Point is, I don't do it intentionally .
Cheers,;) |
|
|
| sreten |
| quote: | Originally posted by fdegrove
Hi,
2-3 feet is too long for MCs.
What type of cartridge are you using?
Ciao,;) |
I don't understand this.
Moving Coils will happily drive very long cables due to their
low output impedance (resistance and inductance).
Moving magnets inductance interacts with the cable and amplifier
capacitance so the cable length is limited by its capacitance/metre.
So max length depends on recommended loading, amplifier input
capacitance and the capacitance/meter of the cable.
Low capacitance cables can be longer than high capacitance cables.
:) sreten. |
|
|
| fdegrove |
Hi,
| quote: | | Moving Coils will happily drive very long cables due to their low output impedance (resistance and inductance). |
Having the MC headamp stage close to the cartridge is an advantage as you avoid cable losses due to series resistance of the cable.
Cheers,;) |
|
|
| sreten |
| quote: | Originally posted by fdegrove
Hi,
Having the MC headamp stage close to the cartridge is an advantage as you avoid cable losses due to series resistance of the cable.
Cheers,;) |
Your having a laugh. What series resistance ?
You must have seen voicecoil wire. How thin it is.
And if you unwind a voicecoil how long it is.
Contact resistance of the connectors dominates.
You can use any cable length you like with a MC.
:) sreten. |
|
|
| fdegrove |
Hi,
| quote: | | You can use any cable length you like with a MC. |
Well, you do what you like.
With the µvoltages coming out of MCs I'd rather not take too many chances so I prefer to do I/V conversion as close to the cartridge as I can.
Cheers,;) |
|
|
| Havoc |
| quote: | | With the µvoltages coming out of MCs I'd rather not take too many chances so I prefer to do I/V conversion as close to the cartridge as I can. |
Bit of a contradiction, not? Microvolts coming out and doing an I/V conversion on them. |
|
|
| fdegrove |
Hi,
| quote: | | Bit of a contradiction, not? Microvolts coming out and doing an I/V conversion on them. |
Sure, you want to convert the tiny current/voltage to workable voltage/current.
It depends on how you do this, I suppose.
Cheers, ;) |
|
|
| sreten |
| quote: | Originally posted by Havoc
Bit of a contradiction, not? Microvolts coming out and doing an I/V conversion on them. |
Not really. If you use shunt feedback and the cartridge resistance
as the input resistor your effectively using the cartridge current to
drive a virtual earth point.
Due to low R MC's can produce lots of current.
MM typically produce 5mV from 1KR, my MC produces 300uV from 10R.
Loading for MM must be ~50K, current = ~ 0.1uA.
recc loading for my MC = 100R, current = ~ 3uA.
(MC power output is nearly twice the MM)
But using shunt feedback into virtual earth, current = 30uA.
(power from the MC is now 18 times that from the MM)
So there is some logic to it, using I/V conversion.
Still doesn't matter how long the lead is though.
update : just seen F's post, seems this isn't what he meant !
:) sreten. |
|
|
| fdegrove |
Hi,
| quote: | | update : just seen F's post, seems this isn't what he meant ! |
No, you're correct, this was exactly what I meant but I also accept there are other ways to do it.
| quote: | | Still doesn't matter how long the lead is though. |
On paper, no, it shouldn't matter but there are external factors such as EMI and RFI that convinced me to keep leadlength short and put my step-up stage as close as possible to the source.
Cheers,;) |
|
|
| Havoc |
There are reasons for not using shunt feedback, like noise behaviour. For me this is the reason not to use this for phone inputs.
But choose whatever you like, after all "de gustibus et coloribus non disputandum est". Not that we do anything else over here....... |
|
|
| fdegrove |
Hi,
Here's the circuit I use as a MC headamp:
MC HAMMER.
Cheers,;) |
|
|
| Havoc |
| Use whatever you like. But valves for low impedance..... (OK, I don't like valves, after all I don't use dos anymore as well) Personaly I use a balanced input, with an LM394H for each arm (4 in total) running at about 2mA. Needs to re-wire your arm for it, but very noise resistant. |
|
|
| leo |
| Sergey, I bet you wish you never asked now:D |
|
|
| fdegrove |
Hi,
| quote: | | Use whatever you like. But valves for low impedance..... |
Well, not just any valve of course.
You need to know what you're doing and the ECC88 is a pretty good candidate for the task at hand.
There aren't too many others especially when you start looking at those still in production...
Cheers,;) |
|
|
| gurevise |
Guys,
I see emotions are running high :-)
If I can stear the subject of discussion back to original question:
Any suggestiosn on DIY phono cable?
I undestand that MM cartridges have high inductance and impedance. All this make them very dependant on capacitance and resistance of the load.
I see that commercially available cables cost 200 $USD and up. Too expensive for me. I would like to make my own phono interconnect.
So, any suggestions on construction and parts for DIY phono interconnect?
Thanks
Sergey
Dayton, OH
USA |
|
|
| sreten |
I used to use this stuff :
4-Core Individually Screened :
A four-core screened cable having each core individually screened,
thus keeping crosstalk to a minimum. Stranded cores, 7/0·1mm
copper conductor with yellow, black, red and white polythene
insulation, lap screened and sheathed overall in grey PVC.
Overall size: 5mm
Nom. conductor area: 0·055mm2
Capacitance (core to screen): 95pF/m
Using the screen for turntable ground and the
4 cores for L+, L-, R+, R -, each pair opposite,
and twisted together after tapping the ground wire.
At the time I could find anything with lower capacitance.
Once you tap off the ground wire the remaining wires
need reinforcing with heatshrink or easier electrical tape.
Not the most exotic looking cable I'll admit.
:) sreten. |
|
|
| sreten |
I should explain that my assumption was the capacitances to
the screen would be in series for each pair, giving I assumed
47pF per metre for each L,R pair.
Specialised low capacitance cable is 13pF/ft, and doesn't suit
the application half as well, L- and R- have to be used for
screening purposes, you need a seperate earth and they
need to be formed into a single run.
:) sreten. |
|
|
| Havoc |
I use standard microphone cable, the flexible type with cotton inside. Two runs, one for left one for right, with XLR connectors. Both screens connected together at the TT side only, not connection at XLR side. Separate GND wire outside the mic cable, everything tie-wrapped together. You need to have both conductors of a pair inside the same screen, otherwise the twisting is not functional. (I could not make this out 100% on sreten description, but I think his construction gives the capacitance in parallel, not series) Soldered to twisted pair made from 0.1mm laquer insulated wire used in the arm itself.
Next will be the arm wire as before, but directly to the preamp inside the base. |
|
|
| sreten |
| quote: | Originally posted by sreten
I should explain that my assumption was the capacitances to
the screen would be in series for each pair, giving I assumed
47pF per metre for each L,R pair.
:) sreten. |
With further thought I don't think this is true.
At the amplifier the earth wire, R- and L- will all be joined together
on nearly all phono input circuits, so more likely 95pF / Metre.
:) sreten. |
|
|
|
