KOETSU VERMILION and audio research PH7

So I guess the output of your phono stage was just not sufficient to drive the Hera linestage for it in turn to produce enough signal voltage to drive your amplifier.  (The results are dependent upon the input sensitivities of each of the components in the chain, not merely their respective capacities to add gain, as I am sure you know but just for others to benefit.)  Clearthink, I beg to differ a little with what you say; most active linestages do add gain, typically 10db to 20db.  Unless one is using a passive attenuator, there will be some added gain from the linestage.  I'm not saying this is a good thing, necessarily; it's just most common in my experience of looking at specs.  A few phono stages that offer the option of being used as full function preamplifiers do use only a cathode follower in the linestage section, which adds no gain but permits the linestage functions, like introduction of a volume control and switching of CDPs, etc.  My Manley Steelhead is like that.

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.

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.. 

You drove me to go to the website. You are correct. Koetsu lists the Vermilion as having an 0.2 millivolt output, much to my surprise. All the other Urushi variants are listed 0.4 millivolts. I can only conclude that something is different about the Vermilion. I don’t recall ever reading anything about it, but you probably do need to proceed on the assumption that the output is 0.2mV. In which case your present phono stage is marginal at best. But it is still not wise to insert an SUT before an MC phono stage.


 I suggest you give it a try with your present set up, and then decide whether in fact you need a higher gain MC phono stage. I think Koetsu measures output at a stylus velocity of 3.54 cm/sec, the old standard. The new standard for many years is 5 cm/sec, which would give a higher stated output. You might luck out if Koetsu is understating the output by current standards. Like I said, my Urushi behaves as if its output is greater than the claimed 0.4mV.

Forgot to say you should be ok as is in terms of gain. My Urushi Wajima  behaves as if it puts out more like 0.5-0.6mV.

First, as wlutke says, the output is at least 0.4mV, unless the cartridge is in the Platinum series, which I doubt because I don’t think Koetsu made a Platinum version of the Urushi types. (Vermilion is essentially a red Urushi.) Second, it’s not a good idea to mate a SUT into an MC phono section even if the input resistance is 47K ohms, because you are very likely to overload the stage. If input R is the more typical 100 ohms or any value much less than 47K, that’s a much worse situation. Don’t do it.