KOETSU VERMILION and audio research PH7

The advice to use a higher gain phono stage may be well taken and I agree it is probably not advisable to add a SUT to the PH7, but not because of noise. If there is a JFET at the input of the PH7, it is likely forming the bottom half of a cascode topology, with a 6922 tube on top. The gain comes from the combination of the JFET with the tube. Such a gain stage is actually very quiet. Or if there is no cascode, if the input gain is all coming from the JFET, that too is low noise.

jlutke notes that at least one Koetsu dealer lists the gain of the Vermillion at 0.4mV. I have to wonder therefore whether the gain listed at the Koetsu website, which was probably created by the US distributor, is possibly in error. Because never before have I read that the gain of any one Urushi model is any different from that of any other.. 

I just noticed my Sonic Frontiers Phono 1 is JFET and 6922 like the PH-7, and with very similar gain. I’m telling you it goes from dead boring with the 0.3mV Koetsus to wonderful with my 0.5mV - 0.6 Shelters, Ortofon, and alnico Koetsu. I also have Rogue Ares Magnum, Herron VTPH-2A, and VAC Renaissance that all go far better with the 0.3 mV Koetsus. The Rogue is good (make sure you get the blue label CineMags), the Herron is a bit better, and the VAC is a lot better but for a lot more money. I like the Bob’s Devices Sky SUTs for the money, and I think they improve on the Herron’s JFET stage. A Sky 30 or 40 would go great with the Vermillion. The Hashimotos are also really good. I don’t like Lundahls. The Koetsu SUT is superb but hard to find.

I did not say, nor did I intend to say, that using a SUT is a bad idea.  I only say that using a SUT with the PH7 would probably be a bad idea.  Because it would likely overload the PH7 resulting in distortion, and because the PH7 at the very least would need to be modified to present a 47K ohm input load resistance, if it doesn't already come so equipped.  Using a SUT with a high quality MM stage might be fine.  Another factor that has been excluded from this discussion is the additional gain, if any, provided by the OP's linestage.  Most linestages add 10db to 20db of additional gain, unless one is using a passive stage. So, mulveling, when you got your mediocre results with 0.3mV cartridges, what was your linestage gain?  I ask, but I don't want to be in the position of insisting that 58db of phono gain is "OK' with an 0.2mV cartridge.  I do agree that more gain is better in this case.

@lewm
At one time I was using that Sonic Frontiers with a Hera II linestage that had gobs of gain (over 20dB, much more gain than the 15dB specd for the Hera I), and it didn’t help pull the dynamics back. Plus very high gain tube amps (over 36dB) and 96 dB / Watt speakers - I wasn’t wanting for gain in the overall system. It could get really really loud, and had a lovely midrange and treble, it was just sad and lifeless with no bass impact. The Koetsu Platinums came to life with any of the other phono stages I listed. I also used the SF in a high end Stax headphone setup (009, T2) with SOTA Nova, and same conclusions with same set of cartridges.

I agree with you, I wouldn’t ever try a SUT with either the Sonic Frontiers or the PH-7. Just the wrong configuration for that.

Check if there is any gain on your line pre-amp.  Most are flat but some have 10 or 12 dB of gain.