advertisement


Step up transformers

Arkless Electronics said:
Very often the best match will involve "non standard" techniques in loading including using Zobel networks on the secondary in conjunction with resistive loading that may be a fair bit away from the standard 47K. This means that for optimum results a specific SUT with specific loading into a specific MM stage and used with a specific cart is the ideal and that the matching will involve use of test gear and knowledge of electronics, ie to conduct frequency sweeps and square wave tests and select precise loading resistance, capacitance and probably Zobel values to optimise for the widest frequency response and minimum ringing on the square waves.
Click to expand...
Yes, for true 47 k loading and 100 Ohm to the MC you want about 22:1 turns ratio
In practice 10:1 is going to be a lot less fussy about loading and only a bit less signal (half the voltage)

SUTs can sound very different with various MM inputs and cables.
 
awl said:
Thanks for all the info and explanation. Arm is 12" Jelco TK850 on a Garrard 301.
Click to expand...

To get the best results the tonearm really needs to be nearer to 20 grams effective mass. You might be better using the N/nude model which is still an excellent cartridge. We used a Royal N at the 2012 Munich show on a TW 10.5 tonearm with Tron electronics driving the 4.5 ton Cessaro Beethoven horn speakers and the sound was extremely good.
 
davidsrsb said:
Yes, for true 47 k loading and 100 Ohm to the MC you want about 22:1 turns ratio
In practice 10:1 is going to be a lot less fussy about loading and only a bit less signal (half the voltage)

SUTs can sound very different with various MM inputs and cables.
Click to expand...

That is true.

For valve phono stages (with internal or external MC transformers) you can more or less forget about cartridge loading. Unless you have a particularly difficult MC cartridge (e.g. Kondo IO-M, Audionote Io models, Allaerts MC2 F1, and some of the Benz cartridges) a good 1:10 or 1:20 SUT will be perfect for 95% of todays MC cartridges as they will be presenting between 100 and 470 ohms to the cartridge, so at least 10 times plus the cartridges internal impedance. The most important factor is making sure you have the correct amount of gain in the SUT for the cartridge. Loading is more specific for solid state phono stages where you might need to curb the cartridge's rising high frequencies above 8-10KHz, which can be much more apparent on your ears when using solid-state electronics.
 
Back on track, I used a Denon AU320 transformer for 30 years. Luckily it had 3 ohm (most low output MCs) and 40 ohm (Denon 103 series) taps. They really need to be carefully matched to the cartridge or the sound will be compromised.
 
I've had 2 SUT's. First was a Noteworthy which was about £200 and now replaced by a Rothwell MCL. MM phono was in a Croft pre replaced by a VTL pre with MM phono.

No problems with loading, hum or anything else and it's very quiet. Cartridges used Koetsu Black, Benz Wood SL, Goldring Eroica. Current cartridges Ortofon Jubilee and Benz Micro Ref S.

I haven't had an MC phono stage that sounds as good but they have all been at the lower price range.
 
davidsrsb said:
Yes, for true 47 k loading and 100 Ohm to the MC you want about 22:1 turns ratio
In practice 10:1 is going to be a lot less fussy about loading and only a bit less signal (half the voltage)

SUTs can sound very different with various MM inputs and cables.
Click to expand...

Yep that makes it less fussy and moves the crap higher and more out the way but at a big penalty in S/N ratio....

Cables? Only as much as the capacitance of the SUT to phono stage I hope you mean...(?). Buy yes it's a transformer.. and it reflects each way so all sorts of strange interactions are possible, hence my comments up thread that ideally the matching needs to be made correct taking into account the parasitic's etc of the SUT, the cart at one end, and the input of the MM stage which may well, for theoretical and measurable optimum results, need to be made lets say 15K resistance with 100pF across it and a Zobel of say 3K3 and 1000pF across that, to get flattest response and minimum overshoot etc with a given SUT... Rather than everything being "just perfect" into a "normal" 47K and say 220pF MM input.

Check out practice in professional mic amps etc with SUT inputs from the likes of Telefunken, Neve, BBC etc....
 
Arkless Electronics said:
Cables? Only as much as the capacitance of the SUT to phono stage I hope you mean...(?)
Click to expand...
Yes the capacitance. With a SUT, the whole cartridge, the transformer, output cable and MM input become a complex resonant system. Add a SUT with tap options and you end up with a very erratic house of cards. Strangely solid state MC inputs with resistance and capacitance loading options are often reviewed that the options have rather limited effects. I think SUTs are for the users who like to experiment
 
G T Audio said:
That is true.

For valve phono stages (with internal or external MC transformers) you can more or less forget about cartridge loading. Unless you have a particularly difficult MC cartridge (e.g. Kondo IO-M, Audionote Io models, Allaerts MC2 F1, and some of the Benz cartridges) a good 1:10 or 1:20 SUT will be perfect for 95% of todays MC cartridges as they will be presenting between 100 and 470 ohms to the cartridge, so at least 10 times plus the cartridges internal impedance. The most important factor is making sure you have the correct amount of gain in the SUT for the cartridge. Loading is more specific for solid state phono stages where you might need to curb the cartridge's rising high frequencies above 8-10KHz, which can be much more apparent on your ears when using solid-state electronics.
Click to expand...

Interesting what you say about loading for a valve phono stage. I bought a pair of Partridge 1:6 SUTs for a Denon DL103 that worked very happily into a valve phono stage. I am currently using a Hana SL with the same setup. I was concerned that 1:6 would be too low for the Hana but it actually works fine. Could it be due to the forgiving valve phono stage?

Edit Having checked the specs I see Denon output is 0.3mV Hana is 0.5mV so shouldn't be a problem. I had the Denon retipped with a Shibata stylus on Aluminium cantilever so they are very comparable cartridges. I must try the Denon again.
 
If anyone is curious about head amp's, by coincedence, following links on the www, I stumbled upon a handful of models, presumably now quite aged, and maybe never available in the UK - finding useful reviews may be quite a challenge.

Yamaha HA-1 - this has been mentioned here on PFM. The model number is also a Yamaha keyboard, just to add confusion and make searching very difficult. There is a 2 input version, the HA-3. There is very little available online about either version of this amp'.
Sony HA-55 - Sony HA-55 on thevintageknob.org HiFi Shark finds two sold in Europe this year.
Denon HA-500 - Denon HA-500 MC Cartridge Head Amplifier Manual | Vinyl Engine Shark finds four currently for sale in Europe, and large numbers listed as sold.
 
Vinny said:
If anyone is curious about head amp's, by coincedence, following links on the www, I stumbled upon a handful of models, presumably now quite aged, and maybe never available in the UK - finding useful reviews may be quite a challenge.

Yamaha HA-1 - this has been mentioned here on PFM. The model number is also a Yamaha keyboard, just to add confusion and make searching very difficult. There is a 2 input version, the HA-3. There is very little available online about either version of this amp'.
Sony HA-55 - Sony HA-55 on thevintageknob.org HiFi Shark finds two sold in Europe this year.
Denon HA-500 - Denon HA-500 MC Cartridge Head Amplifier Manual | Vinyl Engine Shark finds four currently for sale in Europe, and large numbers listed as sold.
Click to expand...

I've had an HA-500 and still have an HA-1000 that I rebuilt. Both excellent devices.
 
Ali T said:
I've had an HA-500 and still have an HA-1000 that I rebuilt. Both excellent devices.
Click to expand...

I have had the very the briefest of looks at the spec's but they all seem to offer only low input impedances comapred to current designs, at least in part because that made them compatible with current MC designs back in the 60-70-80's. Although that still makes them compatible with plenty of current designs, but probably only at their higher impedance setting(s).

What MM stages have you used them into?

Denon HA-1000 MC Cartridge Head Amplifier Manual | HiFi Engine
 
Had a Firebottle initially, then a Modwright SWP 9se. I've also tried it into Nick's Longdog Audio stages. I checked it out when I bought it, found some swollen caps, so replaced all the 'lytics and the tantalums. As good as any of the SUT's I've had (had Luxman, Hashimoto etc in the past, now use a Tribute), though it consistently has a bit more of an up front sound than a SUT, which by comparison are a few rows further back, and give a bit more of a relaxed presentation.
 
For SPU just use a decent active phono amp with enough gain, I've swapped a Kondo S9 for Allnic phono amp and find it quiter and more detailed. If you must SUT then research a good match for your SPU as the internal resistance as well as output is low and may require 1:30 and probably prefer 1:40. Internal resistance is usually only 1-3 ohm and output 0.2mv.
 
runforfree69 said:
If you must SUT then research a good match for your SPU as the internal resistance as well as output is low and may require 1:30 and probably prefer 1:40. Internal resistance is usually only 1-3 ohm and output 0.2mv.
Click to expand...

I am sure that does not read as you intended because as it reads, it isn't true/as simple as you imply.
 
runforfree69 said:
For SPU just use a decent active phono amp with enough gain, I've swapped a Kondo S9 for Allnic phono amp and find it quiter and more detailed. If you must SUT then research a good match for your SPU as the internal resistance as well as output is low and may require 1:30 and probably prefer 1:40. Internal resistance is usually only 1-3 ohm and output 0.2mv.
Click to expand...

It depends on the gain of your phono stage. You shouldn't need anything like 1:40. A good 26dB step-up will work with the vast majority of SPUs with a proper valve MM phono stage with say 48dB of gain (total gain 74dB). The Kondo SUTs work best with Kondo cartridges.
 
You must log in or register to reply here.


advertisement


Back
Top