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Inaudible Hum - Ignore or Not?

antcollinet

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I did.

Changed the amplifier to use a different outlet and surge protector strip from the TT motor (and everything else).
Interesting. No idea why that fixed it, but glad it did.
 

captainbeefheart

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I have found that when using a MC cart a SUT is the only way to go. My favorite was some old RCA 12399 250:50,000 mic transformers that reduced noise and improved the sound quite a bit.

Think about it, a MM only needs something like a gain of 180x, where a MC needs around 3,000x gain which is a huge difference IMHO. Going with a SUT greatly improved my MC experience.

Since then I have found that the sound difference between MC and MM is the fact most don't dial in the loading of capacitance to the MM cart. Taking into consideration your tone arm, cables, and input of preamp you need to evaluate the total capacitance and it's effects on the frequency response. Once I took the time to dial this in I do not notice any improvement with MC over MM and I can replace the stylus cheaply and easily.
 
OP
watchnerd

watchnerd

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I have found that when using a MC cart a SUT is the only way to go.

I have yet to use a SUT that didn't add some coloration.

All of the SUTs I currently have (Lundahl, Hashimoto) do stuff to the bass.

Some may claim that's part of the 'system matching' of analog, or that it adds some euphonic flavor.

And they add yet another possible source of hum, too.
 

pseudoid

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Hey, @watchnerd,
You may have gotten rid of the hum but you still don't know what the root cause of problem is.
Would it be worth examining/measuring the grounds both at the source and the different loads, as well as the interconnects and cart-to-headshell terminals?
 

Angsty

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I have yet to use a SUT that didn't add some coloration.

All of the SUTs I currently have (Lundahl, Hashimoto) do stuff to the bass.

Some may claim that's part of the 'system matching' of analog, or that it adds some euphonic flavor.

And they add yet another possible source of hum, too.
I have two phonos - one with SUTs (Bryston BP-1.5) and one with op amps (Sutherland Insight). I like the Bryston more for its detail, but it costs twice as much. It’s currently in the Bryston shop now for a hum issue, ironically. The Sutherland is very enjoyable and has never had a hum issue.
 
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watchnerd

watchnerd

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Hey, @watchnerd,
You may have gotten rid of the hum but you still don't know what the root cause of problem is.
Would it be worth examining/measuring the grounds both at the source and the different loads, as well as the interconnects and cart-to-headshell terminals?

For what purpose, though?

Problem is solved.
 
Last edited:

captainbeefheart

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I have two phonos - one with SUTs (Bryston BP-1.5) and one with op amps (Sutherland Insight). I like the Bryston more for its detail, but it costs twice as much. It’s currently in the Bryston shop now for a hum issue, ironically. The Sutherland is very enjoyable and has never had a hum issue.

Yes high quality SUT are expensive but I too get better detail, overall it just sounds right to me. I had a very high quality active pre using LT1358 opamps carefully screened for low noise and I did enjoy it but it never sounded as good as a SUT into a vacuum tube MM phono pre. The latter just did everything right for me and it's not even a very complex circuit, literally copied directly out of the RCA handbook for a recommendation for their 7025 tube. It's probably the only thing I'll ever use a 12AX7 for. I have tried a bazillion other phono circuits but I keep coming back to the simple RCA circuit. All that's needed is a very high quality power supply and the circuit just works magic. But I ditched the MC and SUT setup and went back to MM as I found MM can be just as good as MC so long as you get the loading dialed in. My 20x2L wore out and I just want to be able to replace the stylus every couple years or so instead of dropping over $1,000 to replace a MC. If I do go back to MC I'll go with the Audio Technica AT-OC9XEN and a SUT. That AT cart is very good for the money, not as good as the Dynavector but darn close to my old ears.

Do you happen to know what's inside the Sutherland? Curious what opamp they use.

gi.mpl
 

Angsty

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Yes high quality SUT are expensive but I too get better detail, overall it just sounds right to me. I had a very high quality active pre using LT1358 opamps carefully screened for low noise and I did enjoy it but it never sounded as good as a SUT into a vacuum tube MM phono pre. The latter just did everything right for me and it's not even a very complex circuit, literally copied directly out of the RCA handbook for a recommendation for their 7025 tube. It's probably the only thing I'll ever use a 12AX7 for. I have tried a bazillion other phono circuits but I keep coming back to the simple RCA circuit. All that's needed is a very high quality power supply and the circuit just works magic. But I ditched the MC and SUT setup and went back to MM as I found MM can be just as good as MC so long as you get the loading dialed in. My 20x2L wore out and I just want to be able to replace the stylus every couple years or so instead of dropping over $1,000 to replace a MC. If I do go back to MC I'll go with the Audio Technica AT-OC9XEN and a SUT. That AT cart is very good for the money, not as good as the Dynavector but darn close to my old ears.

Do you happen to know what's inside the Sutherland? Curious what opamp they use.

gi.mpl
Per Stereophile, the Insight's two gain stages are handled by a single Texas Instruments OPA228 op-amp per channel.
 

Angsty

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Yes high quality SUT are expensive but I too get better detail, overall it just sounds right to me. I had a very high quality active pre using LT1358 opamps carefully screened for low noise and I did enjoy it but it never sounded as good as a SUT into a vacuum tube MM phono pre. The latter just did everything right for me and it's not even a very complex circuit, literally copied directly out of the RCA handbook for a recommendation for their 7025 tube. It's probably the only thing I'll ever use a 12AX7 for. I have tried a bazillion other phono circuits but I keep coming back to the simple RCA circuit. All that's needed is a very high quality power supply and the circuit just works magic. But I ditched the MC and SUT setup and went back to MM as I found MM can be just as good as MC so long as you get the loading dialed in. My 20x2L wore out and I just want to be able to replace the stylus every couple years or so instead of dropping over $1,000 to replace a MC. If I do go back to MC I'll go with the Audio Technica AT-OC9XEN and a SUT. That AT cart is very good for the money, not as good as the Dynavector but darn close to my old ears.

Do you happen to know what's inside the Sutherland? Curious what opamp they use.

gi.mpl
Several months have passed and I now own a Bryston SUT to use with my Bryston integrated which has a MM only phono. I have been spoiled by the SUTs in my main system phonostage so I thought I’d give a try to another SUT. I found that I did not enjoy the sound of my Sutherland in MC mode on my integrated as much as I did in my main system. Likely some form of confirmation bias, but I got the SUT anyway.
 

Angsty

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Yeah, that SUT works as well as I hoped in my set-up. The integrated MM input with the Bryston TF-2 in front sounds just as good as the Bryston BP-1.5.
 
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