I faced this problem with the two preamps I've converted to phono only. These are from the early 80s - ARC SP-6B and Paragon Model "E" (very, very rare). I decided to convert the unbalanced output of the phono preamps to balanced using transformers.
After using and returning several commercially available converters, I decided to make a semi-custom one. I decided to build the converter shown in the Jensen App Note AS060 (right hand circuit). I have built two of these. They work flawlessly, reduce noise, and have a small 2.7 dB insertion loss. They are truly balanced.
A circuit similar to this is probably incorporated within phono preamps that have unbalanced phono in and balanced phono out.
The transformers are the most expensive at $120 each (you need two, one for each channel), box is $40, the rest of the parts are cheap. Grand total is about $300 and about three hours labor. You can buy most of the parts from Parts Express.
Developing A Short List For A Phono Stage
Current phono stages are a Esoteric E-03 that has a Transfiguration Audio Proteus and Kiseki Blackheart Gen 1 going into it. Second phono stage is a deluxe Pete Millet with a HO Benz Micro Glider going into it.
I have a Denon DP75 and DP80 getting ready to be used. One cartridge is a Sumiko Blackbird Lo, the second one is not picket out yet, but will be a LOMC most likely.
My preamp has only one set of XLR inputs available now.
So the phono stage should have 2 inputs, and XLR outputs.
I do not mind shopping the used market. I need a quality phono stage, but does not need to be a flagship model, as these two tables are nice but not my reference ones. Well the DP80 could be one once done, so maybe I rebalance the system after that.
Have any candidates that meet these parameters?
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I suspect this is well out of budget, but I'll mention it anyway. I have a Boulder 1108 phono-stage. It has two balanced phono inputs, each configured independently, and two balanced outputs. One can use single ended adapters if necessary on either inputs or outputs (I use on the outputs for my single-ended preamp). |
@neonknight , any preference for SS vs tube phono? Budget? |
I went the SUT solution, Fidelity Research FRT-4, not only 3 inputs, front selectable, also PASS for MM, and 4 impedance/transformer settings. Captive RCA out, not XLR. Zero Noise. 3/10/30/100 ohms face designations (i.e. the coil's impedance) resultant impedances: 37/110/141/423 Respective X Factors (signal gain): 35.84x/20.68x/18.27x/10.55x.
https://www.audiogon.com/systems/11318 Entre has a similar more modern SUT with 3 inputs. ET 100. Usually a few for sale on hifishark, none now oddly.
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