Also I forgot to say that now I'm using the Taboo hooked up to a Niles switch box sent to me from Eric (erimille) thank you Eric. I'm using it so I can run the same set of speakers between the Taboo and a Marantz HT amp and it works great with no sound deteriation that I can detect.
                                                                       Dave

Thanks Lon, to think that my amp has only about 25hrs on it at this point and it's supposed to get even better from what I'm hearing now, really amazes me  ;D   I'm still curious to know about the difference of the rectifier tube from the one that's shown in the pic on the site and even in the Taboo's manual, but it sounds so good right now I don't think I'd change anything. Well off to work today for the first time this week thanks to the Taboo, maybe I can get away early today ???                 Dave

[quote author=Scotty
.  It almost looks like a 5U4 type, which would be the wrong type according to the specs.  Are you curious because you like the shape? Or are you wondering if different types can be substituted for the 5Y3?


 Hi Scotty,
       In the Taboo's manual it says the Taboo is designed around the 5y3GT rectifier tube but is compatible with the following alternatives: 5U4, 5AR4, GZ34 and 274B.
   I do like the shape shown in the pic of the rectifier tube on the site, but I'm loving my Taboo the way it has been delivered to me. Just curious because I'm a visual person and noticed it was different, and seeing's how I could'nt check out the amp in a store I was going by the look in the pic.
   Well I went to work and the carpenters are'nt finished yet so I'm going to have another day to listen to music  I have a feeling when my wife gets home today this is what she will be doing to me                        Dave

Sometime later on after I've lived with the Taboo for awhile and gotten to know it really well, I think I may order a set of the exact same tubes that it came with and have them cryo'd to compare the difference etc.
  On a different note a few months back I did some interior work at one of our local TV news reporters house and saw that he had some fine audio gear, we got to talking and I told him about this Taboo amp that I was just about to order and gave him the website to check out.
  Anyhow he really likes the  Intergrated Zen Triode amp and also the Taboo and I told him when my amp gets here and is all broken in he can have it for a few days in his system. I'm leaving on a hiking trip on Sept10th for a week so he can use it that whole week and check it out. It will be neat to see what he thinks, he has a  Arcam cd player, Music Fidelity intergrated amp, Magnum Dynalab tuner, a Rega turntable (I think) and Mirage speakers. He's big into classical music and has hundreds of classical cd's.        
                                                         Dave

Me too, I think he'll be ordering one up. He really likes his speakers so I guess it will all depend on how it drives them and also if his Arcam player puts out the juice to drive the Taboo. I know he had his eye on the SE34I.2 so if the Taboo works out being enough power for his system maybe he will get that and I could get to hear it. Hmmm I wonder if he would let me use it for a few days like I'm letting him ???  Maybe I should re-think this     Dave

Thanks for the info gnat I will give that a go sometime. I think I'd like to have a set of the exact same tubes that my Taboo came with cryo'd one day, just to see how much difference it makes. I'm real happy with the stock tubes that are in it now.
   Hey you did a group cryo buy here a ways back didn't you?, how did that work out?     Dave




 

Here are some distinct design differences between these various rectifiers which are all usually compatable to interchange.



From left to right: RCA 5Y3GT made in the UK by Mullard for RCA. The center tube is an American made 5Y3GT by RCA. The third tube is a GZ34 - 5AR4 type with the "Blackburn" code manufactured by Mullard in Great Britain. *This is labeled for Amperex as a Bugle Boy and you can still make out the cartoon emblem and all designations.

Here are the 5U4G ST style rectifiers which are premium offerings and guaranteed to work in the Taboo.

And a few more "GB" types.

That's a good concept to follow Dave,

It will be interesting to hear your impressions after about 200 hours have stabilized the Taboo. You are right to adjust your familiarity to the stock form first. This is the clearest way to identify how much change actually takes place with various tube rolling.

You now can find out for yourself what various options can provide in overall sound without depending on others to describe the effects. You are really going to be amazed by what lies ahead! The difference lies within the choice you make but it is never set in stone.

BTW: I was testing some of my tube collection and just happened to find the answer to the question about earlier 5U4G tube types constructed with center rods between the plates.

This tube tested at 2400 plate 1 and 2350 for plate 2 out of a maximum range of 3000 on the micromhos scale which shows to have a long healthy life ahead of it. With the smooth black plate construction, this should sound very nice.

This clearly sums up the answer to that question:



U.S. Navy contract dated 1942

Dave,

Take a look back on the first page and re-examine the 5Y3GT rectifiers in the first photo. The first tube on the left was manufactured in the UK by Mullard for RCA. The tube in the center is a standard RCA American made version. You can see a drastic difference in the build construction. The fat base versions are noted to have premium sound character and they do carry a higher cost to obtain. If you want the ultimate in performance, sacrifice must be made. Anything made by Mullard (especially with the "Blackburn" designator) is increasingly hard to find and they are in high demand. We all know about the effect of supply and demand.

A very good alternative which can be had very cheaply is that of acquiring military grade versions which have thicker glass and much larger bases. A good example are those with the WGTA designation preceded by the letters JAN (JOINT ARMY NAVY). These tubes are less prone to shock and vibration with a benefit gained similar to using tube dampers. Military tubes were designed to take the brutal conditions of a battlefield environment.

There are plenty of good 5Y3GT  n.o.s. rectifiers available from well respected brands such as RCA, General Electric, Sylvania, Raytheon, etc.. I have a wide selection of these from every manufacturer, so I can pretty much give a fair analysis for each in side by side comparisons. Since I have the highly regarded Mullard set as well, I can tell you from my perspective that there are indeed differences to prevail.

I will tell you up front that I found the "Mullard" made RCA to be the cream of the crop and it was a hands down decision from my experience. Depth and quality of tone were noticeably improved.

As you may recall, the Taboo used in the review process was of the older version but it is similar to what you have now. Yours has improvements which make the Taboo even better than past! It is much more attractive to say the least. The unit that I have belongs to Bob Z. (Zygi) and I have to send it back to him soon. I guess that means a new Taboo of my own is in the future.

I listened to the 12AU7 (Amperex Bugle Boy) that Bob had in the amp and I never experienced any type of popping sounds or any other odd anomalies associated with its use. Remember, just as the Taboo has been designed to operate optimally with the 5Y3GT, it too has been designed around the 12AX7 as the optimal choice. This however does not mean the best overall solution for your tastes and that is what makes this tube rolling enigma so special. You can dial in your own tailored sound to meet your specific taste in presentation. What’s right for you may subjectively be substandard by another listener's perception and interpretation. The 12AU7 is better suited along with the 12AT7 for use in the output stage of a DAC such as in the Dec685. I preferred the use of an RCA 12AX7A as the driver tube in the Taboo. Not a critical change but it seemed to work conclusively better with my configuration. It really does hinge upon the total package as every tube factor creates a subjective influence upon the entire balance.

I really found my satisfaction level with the Mullard 5Y3GT and the RCA 12AX7A. These brought out infinite detail from the Russian military output tubes. When you hit a synchronized level of tube complement, you will be rewarded with every dominating factor coming into play, thus absolutely apparent once revealed. Once you have gained unprecedented layers of depth  with unrestrained  detail unraveling into space,  and  a  tonal balance so refined that you just have to sit back and marvel in the revelation, you have accomplished your goal. This should not be a difficult task for the Taboo, as it absolutely has the potential to enthrall ones senses with very little coaxing if any at all. The finer class of tubes just add to that extra bit of special flavoring into the mix.

I cannot stress enough, the importance of room acoustics as this has been discussed many times over on the forums. This is the most critical aspect of refined listening and you will never know the true potential of your equipment until a semblance of proper frequency balance has been attained in your environment. This accounts for at least fifty percent of your perceived sound matrix and by far, this makes the most pronounced improvement.

With this established, the next stage of cable refinement and tube upgrades will then reveal their unique qualities, without the masking of detail brought on by bad acoustical colorations within the room. You will be utterly shocked by the transformation that transpires with proper room treatments. The real shock comes when these remedies are removed and you are subjected to the chaos going on around you. That once great sounding stereo now sounds completely intolerable due to the room taking over with its horrible influence.

Dave, and everyone else, if you want to take your listening experience to the ultimate level, you must take heed to this advice. Trust me as others can attest, you will be glad that you did!

I was quite pleased to see that Simon has finally taken control of this situation and everyone should take special notice to what he is doing. (See his work in the room treatment section) He is heading in the right direction for fulfilling the total package and soon he will be expressing his newfound joy with what awaits him in his new environment. One day, everyone here will hear all about his marked improvement and I will just sit back and think, there is another person who finally got the big picture! Once you become an exclusive member of this club, you don’t relinquish your membership!

Anyway, please take that in a positive perspective as many others seem not to put forth much relevancy to this crucial issue.

That is funny about your Daughter’s new found attention span to the musical likes of D. Krall. There may be more to the magic of the Taboo than what meets the eye! Now if she begins to take pleasure with household duties in a self motivated manner, please inform the crew here. Just think what that would do to inspire sales for the Taboo.



As an example, take a look at this link on e-bay. A decent tube on a budget.

http://cgi.ebay.com/rca-5y3gt-electron-audiotube-audio-vacuumtube-tube_W0QQitemZ...

Take care.

Paul

Dave,

I'm so happy you're enjoying the amp and the tube complement!

Keep on enjoying!

I have had my Taboo long enough to do some tube rolling. As far as rectifiers go I like the Mazda 5Y3GT and have used both Mullard GZ34 and International Servicemaster GZ34 made in Japan by Matsushita which is a very, very good sounding tube. I am expecting shipment of a pair of Shuguang 574B rectifiers any day now to give them a try.

For power I am currently using TAD EL84-STR built in China for The Tube Doctor. I ran a set of these in an 18 watt Marshall Guitar Amp and they spun my head around so I tried then in the Taboo, same thing. These are the biggest sounding, loudest power tubes I have tried to date and I have tried a bunch of them. I doubt I will run out of power tubes for the Taboo, I have Genelex (New and NOS), Mullard (New and NOS) Telefunken, Simian, General, Amperex, Phillips mini watt and Russian Ps. These TAD tubes are heavy, a bit shorter and thicker than others and they really glow in the dark. Can't read a book by them but they do run warmer than the rest. My second choice is Genelex or Telefunkin, can't tell much difference between them but they do sound most excellent on softer rock and jazz.

As for the power tube I give the nod to RCA 12AX7A blackplate or clear top. Both easily best Mullard, Brimar or Amperex to my ears. I would try a Telefunkin if I had one.

Anyone out there listening to Rock music should give those TAD tubes a shot. I think you might like them.

The 574 rectifier tubes came Friday and after some burn in seem to have settled down. I think I am going to like them. Nothing I have tried seems to sound really bad in the Taboo, a few stand out but nothing really bad.