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PS audio Stellar vs MP3 Phono

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Posted on May 22, 2022 at 05:43:14
MP
Audiophile

Posts: 26
Joined: July 2, 2001
Has any one had experience with PS audio Stellar phono pre-amp? Wonder how it compares with MP3 phono.

I am using micro-Benz Ruby H (0.6 mv) at this moment. It works fine on MP3 with volume knob at 1-2am.

Also have an old Spectral MCR Signature (0.2mv) too low for MP3.

Thinking about getting Jenzen 347 SUT. A few issues: could not find any place that sells Jenzen 347; Jensen 347 support cartridge impedance up to 72 ohms, lower than Benz Ruby.

Any inside will be appreciated.

 

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You can use the JT-347 with the Ruby no worries., posted on May 23, 2022 at 13:22:56
Ralph
Manufacturer

Posts: 4401
Location: Minnesota
Joined: April 24, 2002
The step-up is 1:8, which would work fine with the MP-3 phono section.

 

RE: You can use the JT-347 with the Ruby no worries., posted on May 23, 2022 at 18:15:21
MP
Audiophile

Posts: 26
Joined: July 2, 2001
Thank you, Ralph. That is wonderful.

I was concerned when I saw JT-347 specs on Jensen website, supporting up to 72 ohm cartridge.

The Benz Ruby H internal impedance is 95 ohms. Assuming MP-3 phono loading is 47K. The 1:8 ratio JT-347 will present a loading impedance of 734 ohms [47000/(8x8)]. The cartridge-SUT loading ratio will be 7.7 (734/95).

Interestingly, I have an unused Ruby H, bought the same time, that has output 0.8 mv (instead of 0.6 mv) and the same 95 ohms internal impedance, according to the accompanied measurement.

Thinking ahead, my eventual goal will be getting MP1, MP 1 has overall 8db more gain than MP3. I would assume MP1 could handle Ruby H without SUT. what ratio SUT would be needed for the 0.2mV Spectral cartridge?

The rest system is M60 MK3.3 and Quad 989 with Zero-former, The only potential future change would be getting MA1 or another pair of M60 for mono-strap.

Lastly, would Grado Reference 1 cartridge 5mV overload MP1 phono? the Grado has worked very well over the years with MP3 with volume setting between 8-10 am.

Thank you so much for your generous support.

 

RE: The cartridge isn't going to care about the load., posted on May 24, 2022 at 09:03:40
Ralph
Manufacturer

Posts: 4401
Location: Minnesota
Joined: April 24, 2002
LOMC cartridge coils are unaffected by loading at audio frequencies. The reason loading is important for so many LOMC phono sections is that they don't handle the RFI generated by the cartridge and tonearm cable very well. The loading resistor detunes the electrical resonance they create in parallel with each other. That in turn reduces the distortion of the phono section, causing it to be less bright.

If the phono section does not care about the RFI then no loading is needed.

SUTs can block the RFI as they don't have the bandwidth for it. That is why some people prefer SUTs with their phono sections.

0.6mV or 0.8mV is fine for the MP-3 running direct. 5mV will not overload the MP-1 phono section.

I would set the SUT up for minimum step up- to get the widest bandwidth possible out of it.

 

RE: You can use the JT-347 with the Ruby no worries., posted on May 24, 2022 at 11:33:59
rclanger
Audiophile

Posts: 317
Location: Connecticut
Joined: March 6, 2007
I ran a .33mv Ortofon using an MP3 and the internal Jensen 347 SUT, with good results.

 

RE: The cartridge isn't going to care about the load., posted on May 24, 2022 at 15:37:13
MP
Audiophile

Posts: 26
Joined: July 2, 2001
Thank you, Ralph.

I will play around with Ruby/MP3 straight for now.

With Brimar CV4033 in the first 4 positions, there is no audible tube noise at listening position with volume setting below 3pm. This set of tubes has held up well for 2 years.

 

RE: You can use the JT-347 with the Ruby no worries., posted on May 24, 2022 at 15:37:43
MP
Audiophile

Posts: 26
Joined: July 2, 2001
Thank you. Good to know.

 

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