Audio Asylum Thread Printer
Get a view of an entire thread on one page
|For Sale Ads|
I know you've read these posts before. Oh hum, as frequent as "What's Spinning"...
I just setup my DL-103 and DIY CineMag. This is my first ever moving coil cartridge; I was previously a Shure V15 Type III and Grado Platinium user.
The CineMag is set for 1:36 with no resistor loading yet. This is only my first hour of listening. I will give my impressions in more detail when the cartridge is broken-in and I have confirmed the best VTA, anti-skate, and VTF. My current VTF is 2.6 gm.
First impressions are the soundstage is much wider and deeper than my Platinum. The background is blacker, if that's possible, and dynamics and musicality are un-&$#@*^ believable. How is this possible, its incredible! Well, now I'm gushing so I better quit.
You know its music when you start salivating and your gut gets woosey. Is it love or great music?!
Here is a heartfelt THANK YOU to Garth for discovering the CineMags and patiently educating me on resistor loading and wiring the CineMag.
How do you set up the ground with a Rega tonearm?
Black/White transformer wires to SUT box ground post. Got that.
Additional wire from SUT box ground post to phono preamp. Got that.
Additional wire from Rega tonearm post (attached under plinth) to SUT box ground post? Not sure.
One other question... how do you create a SUT ground post with a plastic or wood box?
This is the first Cinemag setup I did well over a year ago.
There is only one binding post directly mounted in the wooden box. The SUTs are encased inside potted in beeswax. The black/white SUT case and internal Faraday shield wires are attached to the binding post only.
It is dead silent. The transformers are themselves encased in MuMetal cans and don't really need additional shielding. Several here mount them on top of the box which looks very nice.
In the case of the Rega arm if it has the stock wire the arm ground is attached to the left channel blue cartridge lead which "eventually" finds it's way to ground at the preamp in 99% of cases. The downside is all the grunge gathered by the shield of the cable is fed into the music signal too.
If you added a ground wire to the Rega arm but did not sever the connection inside the arm you haven't changed anything. The added ground wire is redundant and unnecessary. And if you do add the external ground wire you need to connect the ground wire inside the arm to the external ground wire after severing it from the blue wire on the left channel. And don't forget to remove the tab that connects the left channel blue wire to the arm base or it will still be in the ground path or rather the ground is still in the signal path however you want to look at it.
I have not done anything with my Rega tonearm wire (yet).
I'm just trying to figure this Cinemag thing out before I start. I really have no idea what I'm doing. I've read a bunch of posts here about different ways to ground. From your description, it looks like there is no need for a ground going into, or out from, the SUT.
The idea of an external ground wire for the Rega tonearm was from a completely different subject. Someone was asking if it is possible to run tonearm wire externally (to try out different wires before installing them). It was suggested that an external ground wire would be then be necessary. Thanks for info about how the stock tonearm wire and an added ground wire is redundant and unnecessary.
When I said "SUT", I meant the wood box that contains the Cinemag transformers.
I do understand that the Cinemag transformer ground connections must be grounded.
They cost less than $100 a pair for the "naked" transformers plus postage. You'll have to "package" and wire them yourself but it's pretty easy and fun too.
I also have the 103R and the Cinemag. Set at 1:36 with 30k Ohms loading resistor and been "soaring" to vinyl heaven for almost two months now.
FWIW, make sure the loading resistor is place near the preamp side and not the SUT side.
Amandarae, very nice looking arrangement of the step-ups. I have seen your picture before, and you might have mentioned this before in another thread, but what case are you using for the box. Also, do you have any inside pictures available? Finally are these insulating washers between the trannies and the box?
Thanks very much!
With best wishes,
The case was sourced from AES and is the cheap Hammond 4x3x6 with cover. I painted it and drilled the holes. The trannies are sitting on teflon washers so that the tranny enclosure does not touch the metal box. I am sorry that I do not have a picture of the inside. I followed the wiring diagram from Cinemag's website and I recall that Garth posted an instructions on how to interpret them correctly. I do have pics of the SUT with the switch(one for each but can be done by just a single one) incorporated already to change from 1:36 and 1:18 on the fly. Here they are.
Hey Garth! Of course, the transformer does not care. At ideal conditions(lossless), the electrical equivalent of both locations are the same.
But here is my reasoning behind it and please tell me if it has merit.
With the loading resistor close to the SUT, let's assume that a 5 mV output was coming out of the transformer secondary. If we load the the cart with its specified resistance, the voltage will be half for example. Then this signal will travel the, say 1 meter ,interconnect. It is possible that it will be reduce further and S/N will be less if the transmitted signal was less to begin with than the opposite scenario when the whole 5mv signal will travel across the 1m interconnect first before it was halve.
Does it make sense? I do not know. Besides, I should have posted "try loading the SUT near the preamp side and see if there's a difference" instead.
The cartridge "produces" half the voltage of the unloaded condition. It is not a case of the "full voltage" hitting a "resistor brick wall" and being reduced.
The secondary "sees" the load impedance and reflects it to the cartridge through the transformer primary. The load on/at the coils of the cartridge is X or 1/2X or whatever the transformer presents it.
There may be some good reasons (that I don't know) to put the additional parallel resistor at the preamp but that is not one of them.
At least I got straighten out. I was assuming maximum power transfer since a 14 ohm impedance source driving a 14 ohm load. So now I know that it is not really the case. How do you compute the resulting voltage depending on the load values?
Hi Abe! (it's earlier than I thought in SoCal)
here's the formula:
Va = (Vi / Is+Il) * Il
Va = voltage actual
Vi = voltage initial
Is = Impedance source
Il = Impedance load
So you can see for instance 2 / 28 * 14 = 1
As you point out that is max power but not max voltage. But who cares about voltage? Voltage is only loudness.
I still have not done it but it is only a two second change.
Do you really think the transformer cares? In principle when placed at the SUT it is nothing but a resistor with long leads, IE the cable between SUT and preamp. I frankly can't imagine it makes a difference but I need to try it I guess.
...please read my response above. i posted it in the wrong place.
My brother has the 103R and I have the AT OC9. Both of us are using Cinemag trannies and loved the result. Time to load your cart to the specified impedance. The improvement will not be subtle. As for Garth, truly knowledgeable and generous. Happy listening, Godspeed.
No experience using a step-up trans with a 103 but doesn't a 1:36 ratio stepup the voltage to over 10V? Wouldn't many MM stages be hitting overload with that much input voltage (at least on peaks)?
The DL-103R (not the 103 but the same formula applies) is speced by Denon to have an output of 0.25mV@5cm/sec. Cartridges are also speced with the output measured at 3.54cm/sec which is 70% of the first amount. Denon is not the only manufacturer to use 5cm/sec but 3.54cm/sec is a bit more common or standard and when in general other manufacturers are talking about cartridge output and gain etc. 3.54cm/sec is more often assumed.
So "assuming" the output were to be measured at 3.54cm/sec the output is really 0.175mV. And when loaded at the DC resistance the output is halved. Denon and others measure the output at 1000ohm load.
Taking all that into account the input voltage to the phonostage with the 1:36 gain ratio of the SUT is:
0.175mV/2 (0.087mv) * 36 = 3.15mV - perfect for a typical MM input.
Did I answer the question? :-)
with 50 dB of gain (voltage factor=316) one ends up with a final voltage of almost exactly 1V, actually just below the standard CDP output voltage of 2V. You might want to try to avoid phono stages with a gain of much more than 56dB though.
Depending on the exact cartridge being used with the Cinemag set to 1:36 I have on the average 275-375mV total output from phonostage set to 37dB into linestage. And I have power/volume to burn.
Especially with the exuberant gain I have in my Fi Y preamp (23dB) and the sensitivity of my Fi X amp. I don't really need more gain than about 20-30dB from a phonostage if using a step-up.
But since most people have MMs with about 50dB, it is good to know that the step-up is still usable with the 36:1 ratio.
The fear of too much gain was one of the reasons for shying away from the 36:1 step up ratio, but I do get the rationale now. And the output is not so much higher than with 1:10 or 1:20 due to the correct loading.
Thanks for all the great suggestions here! Very much appreciated!
...The load that is presented to the cartridge roughly halves it's output.
That implies that the typical "how much gain do I need?" question really ought to consider loading; at least for LOMC ... I assume for a MM the 47k load dwarft cartridges's impedance.
So for a 103 with 100 ohm loading (assume an active phono stage) the load "sees" about 70% of the voltage (I'm assuming the coil impedance of 40 ohm)?
The Vinyl Engine has a comprehensove article discussing cartridge loading and it's affect on gain.
It's a fry read but very informative..
Born To Tinker!
...When you load a MC cartridge at or near to it's internal impedance it's output drops, I don't have the formula handy but it has been discussed on this forum recently (try a search perhaps).
My cartridge is a DL-103R. I see I mistakenly typed 103 in the text.
The DL-103R has an internal impedence of 14 not the 40 stated for the DL-103.
Also, the specifications that came with the cartridge note its voltage at 0.30 mv. (I am referring to a printout that came in the box specific to the serial number.) However, the setup brochure states the voltage at 0.25 mv.
Per Garth you want to load relative to the internal impedence with a passive device, like a SUT. So, using a 30k resistor I can present a load to the cartridge of 14-15. With an active device, you may want to start at 100 ohm. (See the Vinyl Engine rule of thumb, which I think would suggest 100 to 240.)
"Always Searching for Perfection"
If your printout is similar to mine, then you may notice that the specified load is 47Kohms (my measurement indicated .28mV) - basically no voltage lost due to internal cartridge resistance. If you then crunch the numbers for a more typical 100ohm load (assuming the 14ohm internal resistance) the output will be reduced to about .25mV.
I like my CineMag trannies even more with my AT OC9ML/II!
Garth discovered Gold in California.
Two packages from UPS today 1) CineMags 2) Hammond black box and terminal strips from Antique Electronic Supply. Your excitement is infectuous, guess I better get going on it!!
This post is made possible by the generous support of people like you and our sponsors: