• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Step Up Transformer to lower noise floor?

P

peguinpower

Well-Known Member
I have the last bit of hum on my phono stage. I can hear it at the 75% gain level. My normal listening level is 50.

I have a Sonneteer Sedley phono pre. Im using the MC gain setting. Its a mosfet based phono stage.

I thought that a SUT might do two things. 1) transformers generally sound better and 2) the SUT might be more resistant to EMI/inteference since its ups the voltage and isnt really an amplifier.

Im waiting on a Rothwell MC-1 280 SUT to use on my phono pre on the MM gain setting.

Is this a worthwhile experiment? Or is it doomed to fail?

Thanks.
 
Last edited:
Register to hide this ad
Very worth while in my opinion. Keep the SUT and cables far from anything that might induce noise and the gain from the SUT should be noise free. You might have to play with the grounds to find the quietest setup but I think you will be more than happy.

BillWojo
 
peguinpower said:
Im waiting on a Rothwell MC-1 280 SUT to use on my phono pre on the MM gain setting.

Is this a worthwhile experiment? Or is it doomed to fail?
Click to expand...

IMO trying a SUT with an MM preamp is a worthwhile experiment but know they add complexity versus a MC preamp. For example, there are multiple ways to load the cartridge when using a SUT though I think the Rothwell is fixed at 100ohms when using a MM with a 47kohm load resistor. Also, SUTs from different manufacturers and within a manufacturer's lineup sound different and over time I've gravitated to one manufacturer after using SUTs from three companies. I find SUTs sort of addictive.
 
Count me as one who prefers the SUT to active gain. In my view voltage gain is very difficult to do actively compared to passively at such low signal levels.
 
I don't know if you remember the days back when where all the recording engineers rebelled and decided there would be no more transformers in the recording chain. None in microphones or in microphone mixer inputs or mixer outputs or on limiters compressors equalizers or de-essors. There was distortion and non linearity in transformers, especially in dealing with small signal voltages from microphones. So here we are 50 years later when everything has supposed to have improved and you want to go back to using transformers. I would just want a better full phono stage to line level phono pre- amp and be done with all the issues of grounding a cable location and getting the right load and other issues correct. Remember most SUT's aren't adjustable. Where a great phono pre-amp you can choose the correct load, gain, eq curve and other characteristic to perfectly match your cartridges output to a line input on your pre-amp. If you want a warmer sound change the curve or select a tube unit. If you want more clarity try another curve from a SS unit. The final question is if you never use more than 50% gain why are you worried about what is happening at 75% gain. Why are you playing noisy old LP's anyway if you are worried about gain. What about W&F, and high distortion products from your mistracking angles and rumble , etc? They all make more noise than what you have now! Learn to enjoy the music and quit worrying about something you can't hear at 50%.
 
AvFan said:
IMO trying a SUT with an MM preamp is a worthwhile experiment... ..I find SUTs sort of addictive.
Click to expand...

I also think they’re fun to play with. When you find the right one for your combination of cartridge and phono preamp, your ears will be very happy. I have two that offer the same gain and similar loading. Both sound good with a particular cartridge but one sounds really good.
 
twiiii said:
I don't know if you remember the days back when where all the recording engineers rebelled and decided there would be no more transformers in the recording chain. None in microphones or in microphone mixer inputs or mixer outputs or on limiters compressors equalizers or de-essors. There was distortion and non linearity in transformers, especially in dealing with small signal voltages from microphones. So here we are 50 years later when everything has supposed to have improved and you want to go back to using transformers. I would just want a better full phono stage to line level phono pre- amp and be done with all the issues of grounding a cable location and getting the right load and other issues correct. Remember most SUT's aren't adjustable. Where a great phono pre-amp you can choose the correct load, gain, eq curve and other characteristic to perfectly match your cartridges output to a line input on your pre-amp. If you want a warmer sound change the curve or select a tube unit. If you want more clarity try another curve from a SS unit. The final question is if you never use more than 50% gain why are you worried about what is happening at 75% gain. Why are you playing noisy old LP's anyway if you are worried about gain. What about W&F, and high distortion products from your mistracking angles and rumble , etc? They all make more noise than what you have now! Learn to enjoy the music and quit worrying about something you can't hear at 50%.
Click to expand...

We dont see eye to eye on this, and that's ok. My opinion is that transformers were phased out because they're expensive, bulky, heavy, more involved to design and, did I say, expensive.
 
Last edited:
AvFan said:
IMO trying a SUT with an MM preamp is a worthwhile experiment but know they add complexity versus a MC preamp. For example, there are multiple ways to load the cartridge when using a SUT though I think the Rothwell is fixed at 100ohms when using a MM with a 47kohm load resistor. Also, SUTs from different manufacturers and within a manufacturer's lineup sound different and over time I've gravitated to one manufacturer after using SUTs from three companies. I find SUTs sort of addictive.
Click to expand...

Hi,

I have a very capable phono stage. I can set it to almost any combination from 0 to 330pf, and 47 to 75KOhms. My cartridge likes 100 ohms, the SUT I got is 280 ohms, the MC-1 Special. I have used the cart up to 1000 ohms and it sounds good from 47 - 500 ohms, best around 100-330 ohms.

I also have a tube phono stage incoming, which is going to need the SUT.
 
peguinpower said:
Hi,

I have a very capable phono stage. I can set it to almost any combination from 0 to 330pf, and 47 to 75KOhms. My cartridge likes 100 ohms, the SUT I got is 280 ohms, the MC-1 Special. I have used the cart up to 1000 ohms and it sounds good from 47 - 500 ohms, best around 100-330 ohms.

I also have a tube phono stage incoming, which is going to need the SUT.
Click to expand...

I think you are going to have fun doing the mix-and-match of your components and their adjustments to find what sounds best to you. Maybe you can provide an update after you've had a chance to try some combos.
 
MisterDK said:
I also think they’re fun to play with. When you find the right one for your combination of cartridge and phono preamp, your ears will be very happy. I have two that offer the same gain and similar loading. Both sound good with a particular cartridge but one sounds really good.
Click to expand...

I found a better combination just the other day: Ortofon Cadenza Bronze, Wyn Palmer MM phono preamp and Hashimoto HM-7 SUT. The cool thing in this combo is the cartridge loading is done only on the primary side of the HM-7 and the typical 47kohm resistor in the MM preamp is removed. This is possible because Wyn's preamp does not need the load resistor and the HM-7's were wired for loading on the primary side. It all sounds very, very nice.

I hope the OP enjoys experimenting with combinations of carts, preamps and SUTs.
 
peguinpower said:
I have the last bit of hum on my phono stage. I can hear it at the 75% gain level. My normal listening level is 50.
I have a Sonneteer Sedley phono pre. Im using the MC gain setting. Its a mosfet based phono stage.
Click to expand...
Are you sure the hum is inherent in the phonostage and not coming from the turntable? The way to check is to put shorting plugs into the inputs of the phonostage and listen to what happens to the hum. If the hum stays the same, it's inherent in the phonostage. If the hum disappears, it's because the hum was coming from the turntable.
peguinpower said:
I thought that a SUT might do two things. 1) transformers generally sound better and 2) the SUT might be more resistant to EMI/inteference since its ups the voltage and isnt really an amplifier.
Click to expand...
If the phonostage has some hum, setting it to MM operation will reduce the gain and reduce the hum. If you make up the lost gain with a SUT, you'll get lower hum than you had originally - as long as the SUT isn't picking up hum. Unfortunately, SUTs are prone to hum pick-up and need to be sited so they're not sitting in the magnetic field from a mains transformer somewhere. Fortunately, it's possible to get the hum level down to extremely low levels if the SUT isn't sited carelessly.
As for "transformers generally sound better", there's a possible explanation for that and it was Wyn Palmer who put me on to it. One theory is that feedback generates high order harmonics and sounds bad unless you have lots of feedback. No feedback sounds better than a modest amount of feedback.
Well, transformers have no feedback and they allow you to run the phonostage at lower gain, ie with more feedback, so the overall sound is better. Anyway, that's just a theory.
 
Oh, wow. Rothwell is on here! It's really cool you chimed in. Im excited to own my first SUT.

Not only am I gonna try it on a Sonneteer Sedley SS phono pre, but I also have a low gain Balanced Audio Technology VK-P5 tube phono pre I want to try it on.

So stoked.
 
You must log in or register to reply here.
Back
Top Bottom