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Step up transformer for low output MC

MVV

MVV

pfm Member
Can anyone suggest a step up transformer for low output MC? I've just acquired an Audio Note amp that needs one for the phono stage.
 
You could consider a Step Up Transformer. I use one from Rothwell Audio in the UK. If you speak to Andrew Rothwell the owner he can advise you which models would best suit your cartridge and amplifier. They use a passive transformer and therefore need no mains or battery power supply.
 
MVV said:
Its an Ortofon Cadenza blue. Output voltage at 1 kHz 5 cm/sec - 0.5 mV
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I have the same cartridge and use a pair of Sowter 8055 transformers to good effect, which have now been replaced by Sowter by type 1480.

If you or someone you know has a bit of DIY nous putting a pair of them in a proper enclosure, wiring them up with a 130ohm across the primary to give the correct 100ohm load for the cartridge will work very well indeed.

Edit: assuming the amp has a 47kohm input impedance on the MM phono stage.
 
SUTs are about as much down to personal taste as anything imaginable. Buy two and compare, sell the one you like least and then buy another. Repeat.

Going by what anyone else thinks is verging on pointless.

I tried several with a Delos (and a DV before that), and they varied a lot. I have now tried several head amps and prefer all of those to all the SUTs, and they sound far more alike than probably any two different SUTs.

I have no doubt at all that SUTs (and perhaps head amps) can sound very different depending on what MM stage they are feeding too.

All SUTs are passive - they are transformers. All are designed for use with LOMC cart's (and I would not put much weight in any claimed flavour of LO as being especially compatible with any particular SUT).

All of them into a Croft Micro MM stage here (that is, the stage in a Croft pre. not a stand-alone Croft RIAA).
 
There is no "correct load" for any cart', just a recommended one and lots of pople prefer loadings significantly different to the manufacturer's recommended one - just one of the reasons why SUTs are so unpredicatable as to how anyone likes them, compared to what simple figures suggest.
 
Here's a handy chart of recommended step-up ratios based upon both output voltage and internal coil impedance (assume all are x:1).

If nothing else, these represent a good starting point when shopping about.

Step-Up-ratios.jpg
 
Cart loading does depend on the relationship between physical and electrical damping in the design of the cart suspension. I have been there with the Kontrapunkt B (the predecessor to the Cadenza Blue), I initially preferred a 470ohm load until the rest of the system improved when changing to a 100ohn effective load improved resolution and showed the 470ohm setting to be under damped.
 
The step-up ratios resulting from following that chart seem a lot higher than is generally suggested. With a 0.4mV cartridge the ratio would deliver an output between 6.5 and 8 millivolts, whereas you usually hear of outputs ending up around 5mV or less. Eg. my Ortofon SPU (0.18mV, internal impedance >5 Ohm) is usually recommended to be used with a 1:20 SUT for around 4mV output (I use 1:26), but in the above chart it would end up around 8mV. I wonder why such unusually high ratios are suggested on this chart?
 
No-one has mentioned the horrendous grief with some SUTs in some systems, with hum. Yet.

Oooops, I just did......

Buy and listen, move on etc., as posted previously.
 
Nagraboy said:
The step-up ratios resulting from following that chart seem a lot higher than is generally suggested. With a 0.4mV cartridge the ratio would deliver an output between 6.5 and 8 millivolts, whereas you usually hear of outputs ending up around 5mV or less. Eg. my Ortofon SPU (0.18mV, internal impedance >5 Ohm) is usually recommended to be used with a 1:20 SUT for around 4mV output (I use 1:26), but in the above chart it would end up around 8mV. I wonder why such unusually high ratios are suggested on this chart?
Click to expand...
I only posted this as a rough guide to achieving sufficient gain, as the linked to eBay auction was for a 6:1 ratio Partridge pair.
 
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If you really MUST use a SUT, then something from MFA is ideal as they offer a range of dialable load settings so you can get a presentation you prefer and is not cart specific for whan you change it. Personally having had an MFA Baby Classic (which was great with 6 settings) In my main rig I now prefer an adjustable head amp in my 2nd system, way cheaper and just as flexible for the 4 different carts I use.
 
i use a hasimoto hm3 with a cadenza blue and a hana ml , 2 arms , no hum both cartridges sound better with the step up but the hana sound better to my ears . phil.
 
I use an EAR MC4 which is very flexible and have no issues with hum. I’m also in a very high RF location.
 
Head amp here - sounds better than several SUTs I tried. McKinnie RO III - JC Vendetta head amp clone from en ex-engineer that worked for John - so good I now have 3 as spares (active FET stage is potted unfortunately), plus Vinny’s old faulty one :)
 
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