Cartridge Output Voltage vs. Phono Input Sensitivity Variance Tolerance
- Thread starter Pault73
- Start date
That is correct Jim. I am not disputing the math. However, in practice with a valve/tube phono stage, when you transformer couple an MC cartridge via step-up transformer the AC load presented to the cartridge makes no difference to the sound whether it is 470ohm (1:10 ratio) or 117ohm (1:20 ratio) when presented by the 47K phono stage input impedance. It is the gain that is important to get right, not cartridge loading with a valve/tube phono stage. If people want to fit a resistor to the primary of the SUT then that is up to them but it seems a huge shame to fit a couple of resisters across the beautifully wound cartridge coils, not to mention what that will do to the sound. OK you don't have a choice when using a solid state phono stage, unless it is set for MM and you use an external SUT.
Jim Audiomisc
pfm Member
Not sure why you assumed any need to add esistor to the primary. Is that based on worrying about the change in any load capacitance? (This also, of course, gets transfomed by the transformer.)
Curiously, when I did some comparisons of the situation for MCs vs MMs taking transformers into account, the carts came out to be more similar that people might expect!
https://www.audiomisc.co.uk/HFN/MagneticMyths/MMvsMC.html
Curiously, when I did some comparisons of the situation for MCs vs MMs taking transformers into account, the carts came out to be more similar that people might expect!
https://www.audiomisc.co.uk/HFN/MagneticMyths/MMvsMC.html
Because Jim, that is what people do to get exactly the "correct" load impedance to the cartridge. They solder a resistor of the desired load impedance to the SUT input transformer primary windings. Changing the 47K RIAA input resister which is connected to the secondary of the SUT, especially increasing the resistance to give a recommended reflected load has a detrimental effect to performance so should be kept at 47K or 50K ohms.
However, if an MM cartridge is being used you can go down to 33K or even 20K when using a Decca for example, if that gives a preferred sound.
InSides
dŵr
Is it really? Have you any confirmation on this? I never cared much for the 103R, so this note is quite intriguing.
Amber Audio
This is the Day
The DL-A110 is based on the 103 and is 40 Ohms. Some sites show 14 Ohms by mistake.
The manual shows spec.
multiple image
InSides
dŵr
Yes, that is what I gathered - just the best “regular” DL-103 that Denon could produce now. Bet that headshell has something to add to the performance.
Back to the OP’s original query - no reason it would not be a good match. If you like the 103, go for the anniversary version while you can still get it. Otherwise, there are now nice wooden replicas of said headshell on the ‘bay.
It is very nicely built - I have the first one (or one of the first two) Stan made.
Back to the OP’s original query - no reason it would not be a good match. If you like the 103, go for the anniversary version while you can still get it. Otherwise, there are now nice wooden replicas of said headshell on the ‘bay.
Exclusive Custom-Made Headshell for Denon DL103 Series made of Cocobolo Wood | eBay
1x new headshell with gold-plated finger-lift. - made of exotic African Cocobolo Wood. Denon DL103/DL103R Wood Body Modification Tutorial. 2x fixing screws M2.5 made of brass. - exclusive solution. Shure V15 Type III Wood Body Modification Tutorial.
www.ebay.com
It is very nicely built - I have the first one (or one of the first two) Stan made.
This site contains affiliate links for which pink fish media may be compensated.
krenzler
pfm Member
My bad. Even Denon website show 14 ohm / 0.25mV but yeah a standard 103.
Used to own the DL-103SA which was a very nice version of the 103R.
Used to own the DL-103SA which was a very nice version of the 103R.
Jim Audiomisc
pfm Member
Jim Audiomisc
pfm Member
The DL-A110 is based on the 103 and is 40 Ohms. Some sites show 14 Ohms by mistake.
The manual shows spec.
Presenting 40 Ohms from an amp with 47k input impedance implies using a SUT with a turns ratio of just under 35. So means the voltage will be stepped up by that amount. Assuming I just played the right tune on the buttons of my calc here. Lower ratio may make sense if needed to tweak the response curve but may reduce the available signal power. Choice also would depend on the details of the amp's noise generator values if you want optimum SNR rather than best upconversion of signal power.
Amber Audio
This is the Day
Rothwell have a lot of info on Denon carts and SUTs, they recommend using their MCL with 1:20, you lose a bit of output 4.5mV but the SNR is better.
step-up transformers for Denon cartridges
www.rothwellaudioproducts.co.uk
Jim Audiomisc
pfm Member
I'll look into what they claim and have a think about it. As it is, a quick read just shows a set of assertions which may or may not be reliable for the case. (Part of the problem is getting reliable data on the source, transformer, etc.) However the basic point to keep in mind is that the transformer/amp can't tell source noise from source signal. i.e. If you use a truly passive transformer any noise from the cart gets treated the same as signal. i.e. No change in the presented snr from the cart. Any *added* noise during transfer is due to transformer imperfections, etc. So their basic comment seems questionable.
FWIW Anyone who really wants to understand these matters I'd recommend to find and get a copy of Motchenbacher and Fitchen's book on Low Noise Electronic Design. Need to unearth my copy. Maybe do a page on this sometime that goes into more detail.
FWIW2 My interest in this was mainly driven initially by needing to make amps for signal detectors cooled to Liquid Helium temperatures! Looking for *very* tiny signals. Then transferred that approach to audio later.
Absolutely Jim. That is just one of the reasons why I don't recommend doing it. Second point: Not without a lot of digging...