SUT - electrical theory and practical experience

Hi @intactaudio ,

I have a DIY phonostage based on EAR 834p schematic + EMT TSD 15 + SUT Sun Audio SAT1000 Tamura.

https://www2.big.or.jp/~sunaudio/assem/sat1000_e.html

I use 20 Ohm input (26dB, 1:20). The phonostage has overload points - (1% THD+N) for the 834P were 69.2mV at 1kHz, 260mV at 20kHz, and 7.85mV

I tried 40 Ohm input. But it sounds less good, thinner and less musical.

Before this I used Altec 4722 SUT with Ortofon Jubilee cartage. But I don’t like this SUT with EMT TSD 15.

I tried a modern Houfe T890 SUT and Jensen JT44 SUT. But both are very low resolution and dynamic compared to Altec. I also had Tamura SUT-83TWIN. Bot Tamura transformers are the best.

Alex.

Hi @intactaudio ,

Finally, the overload points (1% THD+N) for the 834P were 69.2mV at 1kHz, 260mV at 20kHz, and 7.85mV at 20Hz.

Hi @rauliruegas ,

Yes I use these Tamura SUT with box build by myself without switches. All wires are directly soldered to RCA. 

But I thinking to built a new box for my DIY phonostage where I want to place SUTs near input tubes. So I can rid of SUT to phonostage interconnects.

Regards,

Alex.

Hi @pindac ,

I had the original EAR 834. I like it but I saw it was built with very cheap components and power supply. Romy The Cat article "End Of Live Phonostage" inspired me to build my DIY EAR 834 with better parts (including air capacitors, z-foil and AN silver Tantalum resistors, Jupiter signal capacitors,...) and power supply with LCLC filtering, parallel voltage regulator based on 0A2 tubes and different other upgrades.

So, my DIY EAR 834 is a different animal compared to the original one. The schematics is very important but the implementation is even more.

Regards,

Alex.

Hi @pindac ,

I’m agree that EAR834p has rich and bloat the lowest frequencies character. This character of the schematic remained despite improving bass resolution and dynamics, and more clean and open height frequencies in the better implemented version. Another factor are speakers. My Altec 604E speakers have dry bass. So it works good all together at least for my taste and for classical and jazz music that I like to listen.
But I can’t agree that all SUTs have the similar sound characteristics. I heard SUT in my system that have thin sound. And in my experience, the difference between different SUTs is huge.

Regards,

Alex

Hi @atmasphere ,

I have a question for you regarding the use of feedback in tube phonostage. Unlike a power amplifier, the frequency response of the RIAA implies a deeper feedback at high frequencies. Is this kind of feedback deep enough to work properly?

Regards,

Alex