2. analog
  3. 158411-132884

Which SUT? .... for .3mv/10 ohms MC cartridge into 3mv MM input sensitivity

Please help me choose a SUT for my 1st MC cartridge.

Now I have more than enough volume using my existing MM cartridges thru my mx110z MM Phono input which says sensitivity 3mv/47k ohms impedance.

AT440ml is 3mv.
Shure 97xe is 4mv
Shure V15VxMR is 5mv
Grado ME+ Mono is 5mv.

coming tomorrow: AT33PTG/2 MC .3mv/10 ohm coil impedance/dc resistance

..................

signal boost, am I getting it right?

1. Is 3mv a MINIMUM strength for the mx110z input?

2. .3mv x 10 = 3mv (+20db correct?) (minimum boost therefore x10/+20db)?

3, if correct, is .3 x 20 = 6mv equiv to +40db?

4. if so, a SUT providing +40db is more than enough for the .3mv and any likely future MC?
.........................

impedance/loading: I am not getting it.

I read about a general rule: coil impedance x 10 for ____?
A33PTG/2: 10 ohm coil x 10 = 100 ohm

too high impedance sounds thin? bright?
too low impedance sounds dull?

(how?) (minimum?) (where?)
......................................................

Thanks as always, and this time I will definitely wait for advice before getting anything. I am not in a hurry for this, Bill will loan me one of his SUT’s until I get my own.

Elliott


elliottbnewcombjr
elliottbnewcombjr OP
5,602 posts
 
this fidelity research FRT-4 is quite versatile
don't anybody buy it, I might buy my 75th birthday gift 3 years early

3 inputs; 3;10; 30; 100 settings AND Pass


https://www.ebay.com/itm/Fidelity-Research-FR-FRT-4-MC-Step-Up-Transformer/224002964237?hash=item34279dfb0d:g:z9MAAOSwGhRetPWr

specs

ManufacturerFidelity-Research/ Fidelity ResearchModel number: FRT-4.
specificationModel Model MC Cartridge Toroidal Core Step-up TransformerNext Impedance 3 ohm/10 ohm/30 ohm/100 ohm switchPASS(selectable) Load impedance 47kΩ to 57kΩ 50kΩPressure increase3Ω:31.1dB(35.84 times)10Ω:26.3dB(20.68x)30Ω:25.2dB(18.27 times)100Ω:20.0dB(10.55 times)
Frequency response 20Hz to 30kHz
Distortion Within measurement error range up to 2 Vrms of output voltage
External dimensions: 170mm (W) x 60mm (H) x 180mm (D)
Purchased new decades ago.Price at the time.54,000 yen (circa 1978)


almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
this fidelity research FRT-4 is quite versatile
don’t anybody buy it, I might buy my 75th birthday gift 3 years early.

I certainly won’t be buying it :-)

Even if I needed it, which I don’t, personally I would not purchase from a seller who ...

-- has more than 3300 items listed for sale at eBay, very few of which have anything to do with audio.  (His "store" states that "we mainly sell Japanese figures, apparel and daily goods");

-- lists this 40+ year old item without providing any indication of whether it has been tested and found to work;

-- has more than 2% negatives among his nearly 1000 feedback ratings in the past 12 months;

-- and is overseas, which might make returning it and obtaining a refund problematical should that be necessary. At the very least you would have to pay return shipping costs, per the stated terms.

Just my $0.02. Regards,

-- Al

jperry
2,454 posts
 
If you want flexibility you should look at this SUT

http://www.miyajima-lab.com/etr-stereo.html
uberwaltz's avatar
uberwaltz
13,381 posts
 
I don’t know of any SUTs which provide a bypass function, although perhaps there are some.
The Denon au-320 most definitely has a straight through bypass option as I have told Elliot in previous threads.

I used mine to run a 0.24mv ZYX into input 1 running at the 1;10 setting and input 2 had a regular MM cart running through it on the bypass selection when in use.
Both worked perfectly well to my ears running into a Manley Chinook (amongst other stages) set at 47k and 60db gain.
And by that I mean QUIET!
I liked the flexibility of having two SUT in one AND a bypass option, gave a lot of options re cartridge choices.
Oh and I liked the prices of used AU-320 units!
So the 0.3mv should be perfectly fine at 1;10 into the mx phono.

YMMV
elliottbnewcombjr OP
5,602 posts
 
hopping about, see some vintage stuff, do these transformers age well?

Denon more modern look, dc in from separate power supply 100v, I'd need a 120/100 pre-transformer.

https://www.ebay.com/itm/DENON-HA-1000-Step-up-transformer-head-amplifier-Working-Properly-F-S-d530/254589438969?epid=1040361048&hash=item3b46b68bf9:g:xqgAAOSweYBesriC

Thorens, 12v, low 22db, high 32db, bypass

https://www.ebay.com/itm/THORENS-Step-up-Transformer-PPA990-NEW-c1091/324210004828?hash=item4b7c6c135c:g:UMcAAOSwYAVefCjm&autorefresh=true

sony 3, 40, pass and front on/off

https://www.ebay.com/itm/SONY-HA-55-MC-cartridge-head-amplifier-Step-Up-Transformer-import-Japan/174120794119?hash=item288a687807:g:rckAAOSw6l1d7pT5

UTC A-11 altec switchable, 16:1 or 32:1

https://www.ebay.com/itm/133457836840

fidelity research frt-3 10 or 30. 26db or 31db, pass

https://www.ebay.com/itm/Fidelity-Research-FRT-3-Step-Up-Transformer-MC-Phono-Cartridge-USED-JAPAN-fr-64/193131068733?hash=item2cf7823d3d:g:y0cAAOSw2YpdapVv

An OLD DOG, like me, 20:1, simply vintage

https://www.ebay.com/itm/Klangfilm-Siemens-T-42-2e-step-up-transformer/133312407153?hash=item1f0a09e671:g:XU0AAOSwiaVeKCWe

Sony in-line blocks HA T10, +26db

https://www.ebay.com/itm/SONY-HA-T10-Step-Up-Transformer-MC-Moving-Coil-Phono-Cartridge-USED-JAPAN-RARE/193131071248?hash=item2cf7824710:g:pYMAAOSwLNpblKR6

Denon HA-500  24db 32db pass

https://www.ebay.com/itm/DENON-HA-500-Step-up-transformer-head-amplifier-AC100V-Free-Shipping-d1030/264728266720?hash=item3da308c7e0:g:UVQAAOSwkZleuiRY

JVC 30 ohm

https://www.ebay.com/itm/JVC-Victor-MC-T100-MC-Step-Up-Transformer/264781535201?hash=item3da63597e1:g:OJAAAOSwy~Je~Ctp

Cinemag 4 ratios:  1:9, 1:12, 1:18 and 1:36 (l or l+r?) (no pass)
1:18 on AT-33PTG/2 would be 5.4mv; 145 ohms

https://www.ebay.com/itm/Moving-Coil-Phono-Step-Up-Transformer-Cinemag-3440AH-4-Ratios-1-9-1-36-MC-SUT/193558279772?hash=item2d10f8f65c:g:pwAAAOSwdehfBJnw

I'll Make My Own

https://www.ebay.com/itm/COIL-WINDING-EQUIPMENT-MODEL-W-S-N-1171-T-440393A-w-FOOT-SWITCH-COUNTER/133247476931?hash=item1f062b24c3:g:LOkAAOSwUHld1tb9

??? Why can't they make one like this ???

https://www.ebay.com/itm/STACO-Energy-3PN1010B-Variable-Auto-Transforer/173800804939?epid=15006512759&hash=item287755d24b:g:EawAAOSwrdlcaySU:sc:FedExHomeDelivery!07062!US!-1

Empty Box ready for your 9 pin transformers of choice

https://www.ebay.com/itm/Moving-Coil-Phono-Step-Up-box-for-RCA-MI-12399-Transformers-MC-SUT-Bogen-T155-HK/193511613150?hash=item2d0e30e2de:g:05gAAOSwcTZeqOW9

same for smaller diameter transformers

https://www.ebay.com/itm/Moving-Coil-Phono-Step-Up-box-for-Sansui-A-603-9-pin-plug-in-Transformers-MCSUT/124163160221?hash=item1ce8b3789d:g:Z2EAAOSwxTZdaaw9

.............................

Finally, Maestro's Remote Controlled Variable Transformer, from the Listening Position. Two required for Stereo

https://www.ebay.com/itm/Lutron-Remote-MA-RH-Maestro-Dual-Control-Dimmer-White-NEW/303506335792?epid=1300142038&hash=item46aa632830:g:kSkAAOSwnAJeX72R

................................

Tiring, but, I had fun seeing how various companies/designers solved things over the years


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