Rhea Noise

The issue here comes down to how much one is sensitive to tube rush. What Xagwell is trying to describe to us sounds like the normal tube rush associated with the Rhea. Since the gain stages are all tube, it is normal to expect some extra tube rush as the gain is increased. Whether or not this is the "ideal" way to apply gain (vs. JFETs) is not really the issue here. There is no question that the Rhea performs extremely well.

Anyone auditioning the Rhea, or any other tube phonostage, is going to have to answer the quesion, how much tube rush does it take to bother you? I came from stages like the EAR 834P which had far more noticeable tube rush than the Rhea. I have used a .25mV denon with the Rhea at a gain setting of about 62dB and still I have to get very close to my speakers to hear any tube rush and it is certainly not audible when the stylus drops. I have swapped out the stock tubes.

Maybe this is semantics, but I don't think of tube rush as noise. If you're hearing more than what I have described then I would tend to think that you are either more sensitive to rush or there is perhaps something amiss with the unit you're listening to.

Dan_ed, I'm in agreement with the comments on tube rush. I find the same true with my Rhea.
For me though when someone denounces tubes totally for use in phono amplification as Rauliruegas did, I have a problem understanding it.

Rauliruegas, my point was that if some of the most beautiful (source) material for music of all time comes though tube equipment in its recording, production, cutter heads, etc how can one argue so vehemently against using tube equipment for the (re)production in ones home? And to that question, you did not answer. For the moment lets not confuse the issue by including all the ancillary components, room acoustics, or even wall current. And yes, I do use live acoustic music as my reference.
Happy Listening!

"The all tube Phonopreamps were not designed for low output MC cartridges. As a fact, this technology is not the right one for use in Phono stages."

I'm sure Jim White of Aesthetix would have a different opinion here. And there are a number of Aesthetix Io users here who have reported excellent success with low output MCs, in particular, the 0.25mv output Koetsus.

I understand the "pain" people have with the Calypso and Rhea. These units seem to be very sensitive to less-than-optimal tubes. All you had to do is read the Calypso review here by Jadem6 and you understand the effort it takes to get these units to perform to impressive levels of musicality.

I run with the 80db gain Aesthetix Io for both Koetsu Rosewood Signature and Clearaudio Accurate. These are both 0.6mv output which work mighty fine with the gain settings at 62db or 68db. I try to set the gain so that I have maximum loudness (mid-high 90 db levels) with the volume control (Aesthetix Callisto Sig) at 2 o'clock or so. In between tracks, at such a high level, I can just barely hear any kind of noise from the seating position. However, as I have reported on other Aesthetix threads here, I have only been able to find 12ax7 tubes from Ei for the first input stage which gives me this very low level of noise. I would love to find an ultra quiet pair of Telefunken or Mullards for this stage. The Sovteks are very quiet in the Io but they simply are far too fatiguing than these other brands. Perhaps you can try the Ei tubes here. They are only $10 so it's worth a try.

John

Once again Thanks for your feedback.. I recently spoke with Mike from Aesthetix. After some tube "gyrations" he concluded the tubes were bad at V 1/2 on both channels. He is burning in a new set for me as I write this. Since I mounted the Shelter 90x, I had to set the gain at 565db using the balance out which increases gain to 62db. The "tube rush" was not typical. This sounded like a LOUD constant wind. It was loud enough that non stereo listeners asked me "what is that noise" Anyway I compliment the tech support from Aesthetix, and we'll see if these different tubes are quieter. Once again thanks for your feedback. I learn so much from the posts.

Like most Rhea owners in this forum I too have had tube issues since the day I purchased it; however, I recently purchased a VTV tube characterizer that solved my problems. I have been able to go through old tubes and find nice matched pairs that work in V1/V2. The VTV immediately screens out noisy or microphonic tubes.

I also learned some things from the good folks at Aesthetix that can save you money.

V1/V2 require longplates which are expensive if you want NOS matched, balanced, quiet non microphonic. But it was explained to me that V1R/V2R work as a pair that needs to be matched to V1L/V2L. For example assume that V1R is 100/100 and V2R is 90/90. These two tubes could be matched with V1L at 98/92 and V2L at 92/98. If you add the gain you get 95 for each of the four triodes which is what you want. Remember V1R + V2R = V1L + V2L

I've also found you don't need to match the gain perfectly as in my example but just get it as close as your ear can tell. The tubes don't need to be perfectly balanced either but probably should be within 10%. They key is that they not be noisy. Nosiy tubes sound like wind and it's not tube rush because it varies in volume intensity. I have found that tubes that sounded slightly microphonic can work well too. More microphonic ones can sometimes be helped with a Herbies damper but really microphonic tubes ring when I touch the chassis.

Having said all that the Sovtek LPS are the quietest tubes I've tested so far. I got lucky with NOS tubes. I found some NOS early 50's Philips longplates that tested absolutely perfect as well as a few pairs of perfect Mullard 10M's, one pair of which is in V3 and the other in my Calypso. None of these NOS tubes were more quiet than the Sovteks but they were just about equal. I have some matched Brimar CV4004's in V4 and Philips 7308 SQ in V5.

I've had this setup for about a week now and I'm still pinching myself. After six months of one tube hassle after another some of which were of my own doing, I'm now in audio nirvana. The Philips tubes are 3D like. This is not the same Rhea I purchased. It sounds awesome now as opposed to great when it was working before. The noise is not an issue and I'm using an .24mv Airy at 68db balanced. It also works at 75db rca but it pops at 75db balanced. I'm not sure whether it's supposed to work at 75db balanced or not.

I wish I'd bought the VTV right away. It's expensive but it will pay for itself in the long.