Aesthetix Io-Reliability Problems???

I have heard recently from several sources that the Aesthetix Io phono stage has reliability problems and that it runs through tubes very quickly. What has been the experience of Aesthetix Io owners? What types of failures have occured? Are there any non-owners who know the details of the problems? Since I am interested in the Aesthetix Callisto linestage, which is much simpler and carries fewer tubes, I would like to know if the problems with the Io extend to the Callisto as well. Thanks in advance very much for your help.
P.S. I am interested in hearing about good experiences as well as nad re reliability and sonics.

I have had only one pilot error problem (my fault) with Aesthetix Io (volume conrols) in two plus years of very continous use. Jim White has been fantastic with responding to my needs. I had the second power supply added to my unit and WOW that makes the music performance even better.
Hi Gerry,

How many times have you had to change tubes in those two years? What is a pilot error problem?

Ray Hall
Pilot error problem. Now I get it! . Still, I would like to know about the number of tube changes.
Hi Gerry,
Now I come in with questions too:
1. Tube changes?
2. Did you keep the original brands?
3. What is a "second power supply" ? An upgrade or beefed up version or are you cascading them in a way unsing two supplies, which to me seems unlikely, though.
Albert Porter has immense experience with the IO and Callisto. I know he has experimented with many varieties of glass. Hopefully, he will share his wisdom.
I have three different tube sets for each area of Jim White's Aesthetix design. Stock Sovteks of course for everything and they were pretty good. I am doing this from work right now and don't have the exact facts in front of me right now. Please feel free to E-mail me directly if you want the exact specific brand and tube types. So go easy on me if I am misspelling the brand names in the following tidbits. Still going from my memory the preamp section I got NOS Mullard and Mazda special selects. For the PS I got extra Mullard EL34s and then went to Genelex KT-66s. Jim White can customize the pre-amp area to accept two power supplies. Note the standard product has one very hefty separate power 19X22X6 supply. With Jim's mod you then get to add another one just like it for even better power supply reserve, regulation, and lower noise. How much does this really helps - is subject to your interpretation of the final results. Jim is very happy with the standard product, as he has designed. I like the tube changes that I have dove and adding the extra power supply. BTW: Albert Porter was great in helping and suggestion way to change the sound. He really knows the sound of many tubes. Also, Ken at Upscale Audio was extremely helpful on tubes sound characteristic and getting me great NOS tubes. Hope this helps. Also, Jim White was very responsive and treated me very well even when I did a dumb ass thing like having a wrong tube type in the wrong place. Amazing that it worked at all. BTW: do e-mail me, because I want to continue the good practice of assisting others that people like Albert Porter practice on this site.
Gerrym5: It is endlessly refreshing to encounter people like you and Albert Porter (and many others on this site) who are not only dedicated and humble audiophiles, but are genuinely sincere and generous with their long-accumulated knowledege. This is an infrequently-acknowleged aspect of the hobby that gives me (and, I surmise, many others) great pride. While I do not have your skills, I certainly try to reciprocate all the pearls. A heartfelt THANK YOU to all of your ilk!
I just purchased a used Aethetix Io and the previous owner is a super-tweaker. He sets up turntables for various companies around the North East. Anyway, although he replaced the tubes once, according to him, the biggest improvement to the Io was using copper shielding foil on all of the transformers. Although I haven't done the AB myself, I trust his expert opinion on this. I figured that leaving it in place could only make things better. He also upgraded some of the internal wiring to Audio Note silver.
Has anyone compared this unit against the Hovland H-100 preamp and phono stage?
Thanks for any input!
I have used the Io for some time, and was the first to implement the dual power supplies. I have now done this with the Callisto as well. The Callisto is the matching preamp from Aesthetix. On tubes, I started with stock and after some break in, decided to change critical positions to improve the sound. The first four 12AX7 tubes (near the input jacks) are VERY critical, and any noise or microphonics in that position are going to make your life miserable. If you get professional help with any tube selection at all, make it these four. Other tubes that make a big difference is to replace the two Sovtek 6SN7 with the RCA 5692. The old military red base 5692 is the best, but the black plate RCA 6SN7 is a great choice as well. The Sovtek 6922 tubes used in the output of the Io are so bad, that almost any brand is better. I like the Telefunken 6DJ8, the Mullard 6922 white dot, and Amperex 7308 all nearly equal. The sound of these three sets of tubes is radically different, and the correct choice is in the ears of the beholder. The Sovtek 12AX7 tubes used in the outboard power supply, while audible, are not a good place to begin. Going to something extreme like the Telefunken 12AX7 ( as I have ) will be audible, however everything else needs to be at the limit, for this to pay off. Changing the EL34 tubes right beside the 12AX7's (still speaking of power supply) have a large effect on the sound. The two best are the MO Valve KT66 and the Mullard EL34. I have tried almost every tube that will plug in that socket, and these two are by far the best. To respond to the question of reliability, I run my Io 24 hours a day, NEVER turning it off. I pulled the Telefunken 12AX7 and MO Valve KT66 tubes from the two power supplies, and tested them against the recorded numbers from the year before. The loss in trans conductance was only about 12%. At this rate, the power supplies should run 24 / 7 for about 4 or 5 years. Upon testing the main unit, the numbers showed the 5692 (replacement for 6SN7) at about 15% loss in the first year, and the Mullard 6922 white dots (only about 6 months old now) show no loss at all. The main problem with this unit is the fact that ALL the gain is with 9 pin miniature tubes. There are no MOSfets or transistors at all to do this amplification. To make matters more volatile, the circuit uses NO feedback and is run with extremely high gain. This unit will take the .5 MV signal from a moving coil cartridge, and drive 40 feet of interconnect to amps requiring 5 volts peak to peak input signal. There is not another product requiring so much from the first few tubes in a step up stage. This simply means that some people are going to have terrible luck with plugging in tubes (especially UNTESTED) and others will have no problem at all. I think this unit fares pretty well as far as maintenance, but with the small signals from your phono cartridge being magnified with microscope like gain, care must be taken. If you have a problem or make a mistake, it will show up. The good news is that if this phono amplifier is set up correctly, it is without question the best product of it's type I have ever heard. The nearest competitor was the Magnum Opus phono from EASE. The EASE was the evolved version of the Counterpoint SA9, both units designed and manufactured by Mike Elliott. If the SA9 or Magnum Opus phono were still made today, I would tell anyone wanting zero hassle with front end tubes to give these units a listen. They are not as magic, silky or dynamic, because the first stage is a FET, but that FET resolves all the issues I spoke of concerning finding perfect tubes for the first stage. I hope this helps explain what and why and hopefully will allow others to make a decision you can live with. I would be pleased to offer suggestions as to which tubes, if a description of the current system sound is given, and a goal as to what you wish you could change about the sound and tonal balance.
I will be auditioning an Aesthetix Callisto against the Hovland this Sat. If you'd like, I can post my impressions here or you can send me an email and I will post to you privately afterwards. Albert and Gerrym5: Thanks for your informative posts of tube rolling options for the Io. Thanks also Gerrym5 and Albert, for your positive reliability info concerning the Io and the Callisto. If I end up buying the Callisto this weekend, I may bother you, Albert, one more time about changing the stock tubes in the audio chassis. I concur with Hungryear about the generosity of many people at Audiogon in sharing their experiences. This is especially true of Albert Porter with whom I have had several private email conversations as well as forum exchanges. Both of you have already helped me to weigh my risks concerning this expensive purchase. In fact, thanks to all who have posted so far. Is there any bad news about the Callisto or rhe Io? Feel free to sing its praises or describe your fustrations or disapointments re these products.
as a previously solid-state only guy with no tube experience, the aesthetix io i have owned for one year has been surprisingly perfect. i expected some grief but have had none. the performance to me has been beyond what i thought was possible and exceeded the raves i had heard. i also have a marantz sa-1 sacd player and the io is degrees better.

after reading this thread i am excited at the prospects of improving the performance but am still alittle timid about getting into tube rolling. when i purchased the io i also bought a second set of tubes for a very reasonable $275 and had planned to just wait until the first set wore out.

the io is on about 15 hours a week; so about 800 hours so far. it is interesting to hear about opinions on leaving the io on 24/7. due to room size and lack of air conditioning not an option for me. also the 2nd power supply would great but again no space.

anyway, the io has been absolutly perfect and i believe a great value for the dollar.

hope this helps.

mike lavigne

Albert: I'm awed by your generosity re: the above IO post. I do not wish to drain any more of your time, either. One question: I'm curious to know what were the sound benefits in adding the 2nd power supply to the IO and Callisto? Were they very significant? Remember most of us have Mickey-Mouse gear compared to you (no offence to others intended!), so I wonder whether the power modifications would be that significant on lower-priced gear (yeah, I'm aware that bucks do not a great system make).
I have owned and marveled at my Aesthetix Io for two years now. It is, IMO, a supreme phono stage. One month after I received it, it did go down and was repaired and turned around by Jim White very quickly. It has performed flawlessly since with performance that is very, very satisfying. I installed NOS tubes (Mazda and Tungsram 12AX7's, Amperex PQ 6922's, Sylvania VT-231's, Sylvania 5932's in place of EL34's) soon after I first received the Io and, with the exception of the 5932's, the original NOS tubes remain in place and still sound mighty fine. I was told by Jim White that the EL34's and 6922's would need replacing a bit more often. Other than that, the tubes should last a reasonable amount of time.

I too have heard the talk regarding the Io and reliability problems. I sympathize with anyone not able to enjoy the remarkable performance of the Io due to reliability. I happen to be one of the lucky ones to have an Io that has been little trouble and a whole lotta fun. I'm certain that there are many others that have had similar experiences with the Io. If there are indeed reliability problems generally with the Io, perhaps Jim White should be given a chance to correct them and perhaps in the process improve an already stunning performer. There's always a bit of sweat involved with the use of tubed gear, the Io is no exception. Thankfully, the rewards can be great as is the case with the Aesthetix Io.


Joe Mendez
I have had the Io for about a year and quite simply it is a stunning piece of equipment. I have had one problem with my unit and that is, it blows a fuse about every month or two. It is either the right or left fuse inside the power supply. I can find no apparent reason for this (line surges etc.). The Io sounds great but it is annoying to have to keep changing fuses. I have taken to leaving the top off the power supply to make it easier. If anyone has an explanation for this please let me know. Also, I am considering a tube swap for the stock tubes. I am pretty happy with my system but if I could ask for anything it would be a bit more magic and presence in the mid-range and a touch more sweetness in the highs (violins) without losing any air or detail. Any thoughts???
Thanks Bud for your post. What Bud says is also very important to me. I have a system which is on the dark sounding side already. I had the impression that the Callisto, as delivered with the stock tubes, might be a little on the dark side as well. If anyone agrees that either the Callisto or Io is a little warm sounding with the stock tubes, was anyone able to bring out the upper midrange life, breadth and beauty of either of these units with tube changes?
Responding to the request by Hungryear, a second power supply adds to the Aesthetix's sense of ease and effortlessness. There is an significant increase in both the intensity and headroom, while allowing each individual instrument ( particularly piano ) to show off all their colors and micro dynamics. This change does not appreciably alter the tonal balance, compared to the single supply. It does increase the depth of the soundstage, and with a better sense of location. This increased resolution is not the hyper variety, it does this by it untangling similar sounds, and providing a precise location within the listening space. With both my Io and Callisto running dual power supplies, this is the most dynamic and effortless presentation I have ever had. For this to make sense from a financial standpoint, all the other pieces in the system must be able to resolve this improvement. Regarding the comments by Bud and Rayhall, the 6922 Sovtek would be my first change. For additional midrange and air, try the Siemens 6922 CCa or the Amperex US Military 7308 CEP. If either of these produce too much midrange presence, try the Mullard 6922 (gold pin). Realize, that when you upgrade to one of these higher resolution NOS 6922's you are listening with more intensity to the weaknesses of the remaining (original) tubes. You are judging the replacement, plus all that it exposes downstream. If after changing to the CCa or CEP, you find that there is too much "grit" in the sound, try swapping the 6SN-7 as described in my long post. After that, if you are feeling adventuresome, trade out the first stage 12AX7 tubes (Io only). Note, these 12AX7's are the ones I warned about, get TESTED, ultra noise tubes for this position. My first choice and the most beautiful sound is the Telefunken 12AX7. Other options are the RCA 5751, a US Military version of the 12AX7. The 5751 will alter the tonal balance somewhat, as it is not an exact replacement. There will be a slight loss in gain, with improved signal to noise and lower distortion. Overall, the sound will be a bit more on the dry side. One final suggestion would be the 12AX7 French Mazda. A good sample of this will produce significant improvements in high frequency transparency, especially compared to the Sovtek. However, the Mazda has not been without problems in my experience. The samples I received are not equally reliable or equally low noise. Some will play perfectly for many months while retaining their original "voice" while other samples will develop horrible microphonics and tube noise in as little as a week. This is a situation that could lead to disappointment with the Io, when in fact, the tubes are the culprit. Unfortunately, there must be some risk and experimentation within your own system to determine what is best. All the tubes I have suggested here are expensive to buy right now and will become even more so as time goes by. You should never consider their purchase as a potential mistake. If these tubes do not work in your system now, there will come a time when they will be the perfect answer.
Albert, I've been downrated in this thread, when expressing my respect and my thanks for sharing your expertise with us, but I'll do so again, becuase though you did not address me directly, you have helped me a lot to understand better.
I've been asked by Rush Paul to contribute my experiences with the Io. I purchased the Io w/attenuators in early 1998 from my dealer in Denver. This was prior to the numerous favorable reviews in rags like TA$, etc, which caused Jim to be swamped with orders.

While I may differ on some tube choices, I agree with Albert Porter that the unit benefits greatly from NOS tube replacement. The choices will rely personal taste and require experimentation.

With respect to reliability, I experienced only one problem in the two years I owned the Io. I had inadvertently left the unit on for several days and the left channel went out. I emphatically disagree with leaving it on 24/7 unless you are providing your on clean power.

If you've been under the hood of the Io, you will see that Jim has used both plate voltage regulation (SS) and constant current sinks to better linearize the cathode followers. These devices, unlike tubes, can fail instantly with line spikes. My Io was plugged directly into the wall outlet (dedicated circuit) because there isn't an "audiophile" power "conditioner" out there that doesn't limit dymanics. Obviously, the unit had seen some trash on the line and it took out the first stage VR and CCS. Jim fixed the unit rapidly under warranty.

I sold the Io in February, 2000, to the reviewer for Ultimate Audio and it was used in the UA review. At the time, I considered it the premier commercial unit available.

Can the Io be bettered? Absolutely! Anything built to a price point can be bettered.

I think there is likely only one commercial unit on the market that would exceed the Io's performance, and that's the Wavac phono designed by the late Nobu Shishido. I don't know how much longer that unit will be available since Hirata Electric closed their Tango transformer division last October. The Wava uses a Tango step-up on the inputs and the excellent low impedance Tango LCR RIAA module. The use of high quality transformer and inductors in the EQ is a far superior approach to the typical stringing together of CF gain stages.

IMO, there is no unit using transistors at any price that would even merit consideration in the breath as the IO and the Wavac unit.

The preamp I am currently using is a variant on the Soul Sister (line) and Groove Thang (phono) published in the e-zine VALVE. ( It has a custom step-up at the inputs (1:20, from Sowter in the UK wound
with wire from PHY-HP in France). Those feeds a first stage 6ER5/EC95 (a frame grid single triode) that is actively loaded (CCS) and shunt regulated
with a pair of 0D3 gas regulator tubes. Passive RIAA that employs correctly the 3.18 uS time constant between that and the second 6ER5, also actively loaded with a shunt reg. The phono section is cap coupled to a single 76 (again actively loaded and shunt regulated) in
the line section. Output is transformer coupled in parallel feed topology using a MagneQuest nickel core line output tranny (15K:500). Power supply is separate and is larger than the Io's. Completely dual mono, including
separate AC cords. Separate, DC current-regulated heater supplies for each stage and channel and no electrolytics in the B+ rail.

Better dynamics and a greater ease of presentation than the Io. Does all the ersatz "audiophile" tricks the reviewers fawn over, but also gets, most importantly, tone and timbre correct, which is a weakenss of the Io by comparison. Pace, rhythm and timing are set by the musicians and are free of the constrained and slightly sluggish presentation of commercial units. In short, there's more there there.

Those interested in this DIY apprach and the planned revisions to the preamp described above, feel free to e-mail. I'm not an Audiogon member and do not frequent the board, so replies here will likely go unseen.
That reviewer for UA has in turn sold the Io due to what he perceives as long term reliability problems. What these long term problems are is anyone's guess. While I'm sure the Io can be bettered, it is still a phono stage to be reckoned with and in my experience with atleast 7 other top stages, the best out there. Obviously, my experience is far more limited than others.
Well, when he received the unit from me he said it was damaged and didn't make a sound. Turns outr one of the EL-34s had worked loose in it's socket and blew a fuse. Of course, being a reviewer he didn't check the fuse and sent it to Jim White for "repair". At my expense.

I spend more time at my workbench now and less paying attention to mainstream high-end, so the unit's reputation for unreliability was news to me. My one problem was my fault, I believe, because I failed to turn the unit off and the failure was either thermally related or due to line spikes (or both).

As for sound, I said it was quite good, perhaps the best commercially available - I haven't has the opportunity to hear the Wavac, assuming it remains available. But there are DIY circuits out there that improve on the Io.

One of the unavaoidable weaknessess of commercial tube units is that they must rely on current production tubes. The 12AX7 and its variants aren't very linear but are chosen solely for the ease of use (size) and amplification factor (100). The tube was developed in the early '50s in response to what was perceived as a market trend toward minituization in home electronics. Two triodes in a miniature package with a high mu is a bean counter's dream. The 6922 is marginally a better tube, as is the 6SN7. The use of the popular cathode follower circuit and variants for the low noise and gain offered ignores it's tendency to wander all over the map in terms of operating points means that additional steps in the forms of voltage regulation, active plate loading and a current sink must be used to clamp the tube's OPs with a narrow, desireable range.

None of these tubes, however, exhibit the low level linearity of the directly heated single triodes from radio's early days. Unfortunately, these tubes are no longer made and are therefore not feasible for a commercial venture.

In addition, these are low-mu triodes with amplification factors ranging from 3 to 9. So the problem is where to get the extra gain. The solution is in the use of high-quality interstage transformers and plate chokes. This produces a stage-to-stage stability that can't be equalled by cap coupling and it gets the cap out of the signal path. It also allows employment of the simpler anode follower topology, and even topologies like parallel feed which removes the chore of handling DC current from the interstage primaries. This nallows more permeable core materials to be employed and the result is better clarity, better low level detail, and an overall ease of presentation. Of course, your replaced a $1 part with something that will cost $60 on up to several hundred dollars, depending on circuit requirements and core materials.

This makes it difficult to turn the necessary profit since the market is small and the high-end rule-of-thumb sets MSRP at 5x to 8x the cost of parts. But it undeniably a superior approach if cost is no object. See the schematices at Sakuma-san's Direct HEating site ( for both amps and preamps that employ these techniques.

All of these circuits are invariably less complex - a good thing - and make liberal use of high-quality transformers and chokes that replace highly variable (in a QA/QC sense) resistors, caps, and silicon devices. As Einstein said, "Make is simple as possible but no simpler." The Io's complexity, coupled with increased demand for a product that is essentially the designer's second job, may have something to do with the reliability issue.
I am aghast with some of the long-term reliability comments being made here with out any specifics details on those problems and the resolution of them. I am user for over two plus years and no Aesthetix caused problems period. Yet on the other hand I am a tweeker I am a tweeker-DIY, and I make many more mistakes than the manufactures. Maybe what we have here is a great design, complex true, which is getting us 80db gain in a phono stage with out a step up transformer. Maybe there are just too many tubes to not touch. I am glad Albert chained in with a detail brand description of the possible tube changes on could make to better suit you personal music taste. Because, I've been doing this type of thing since 1955 I did immediately go the route of NOS (along Albert's suggestions), But I do have to emphasis several points here the Aesthetix in its stock form (per review) is one of the best phono pre-amps in the world. The best, No! That is always you're personal choice and very subjective. I found the Aesthetix Io to be the only phono circuit that could drive my very low output MC with the music I was looking for and with too much noise. The second point is that Jim White does recommend changing to stock tubes to other NOS brands although he knows that people like Albert and myself will do exactly that. Still, Jim White has been just great to me when I made an error on my unit. He figured it out for me and we were off and running again. The last point I would make is that I do use the French Mazda's in the first phono stages and I had no problems at all. These French Mazda's are very transparent, fast, detail and very low noise. Perfect for that stage. With all this will an Aesthetix be right for you and your system, you knows? There are a lot of very good pre-amp (phono) out there - go and listen. Try to find out about reliability, but trust people that will give specifics with the equipment they have actually owned for a while.
I bought a SH Io and have not had any problems over the past five months.
However a friend of mine bought an Io new approx eight months ago and he uses his sparingly. Before Christmas it developed an intermittant noise in one channel. Swopping the tubes over, did not change anything. He shipped it back to Jim White who promptly replaced a cap and shipped it back second day. He was delighted with such speedy service.

I have a set of Mazdas for the primary gain stage, but have not installed them yet. Been breaking in some new 300B tubes in my VAC Renaissance monoblocks..

Its a stunning phono stage, I have not heard its equal.