audio with realistic timbre

Poweramplifier

Recently I got my hands on the TJ300B. This power tube has a mesh-plate, is of Chinese manufacturing tube but in contradiction to most other chinese tubes, this one is is beautifully made. A nice globe shape, and at night you can see the filament shining through the plate. But that is not why it is on my power-amp.I am a real 45 fan, the mids and highs of that tube are of another world, that is, until I heard the TJ300B.... This one has the magics of the 45 combined with the power of a 300B and a better defined soundstage as a bonus!. I can only say: hearing is believing! Thosten, I fully agree with you. The ER-231 driving-days are over though... Although the TJ does not sound like a typical 300B, it is electrically a 300B. The UX171A does the driving these days. This tube is, in my opninion, the rival of the 45. Less power that's for sure. Its filament is lit through a lead-acid battery and is interstage coupled (Lundahl LL1660/1:2) The TJ works at an B+ of 400V at a mere 60mA... A little bit low, you might think, but: give it a try! I for sure don't need the "full 8 watts" and the tube sounds o so liquid at these values....

De eindversterker, monoblock, met de UX171A als driver en de TJ300B als eindbuis.

The TJ I use, has a 2.5V filament instead of the normal 5V. This made it very easy to substitute the TJ for the 45 and 2A3's I normally use. Since my power transformer has various high-voltage taps, the power supply was quickly adjusted... In my system, the TJ is as silent as a 45 when using AC-filament. In my opninion, 2,5V AC on the power tubes filament is as high as you can go when using 93dB and plus speakers... The hum will be "unbearable" when using 4V or higher....
You can see the schematic here.

..a giant rectifier: the Valvo G4004.. ..the UX245 as driver: if you want power!.. 19-10-2002

An update on the power amplifier... I've been using the UX 171A as a driver for a long time now, and am very pleased with its performance. Yet, if looking at schematics from, lets say, Sakuma and others, a powertube is often used as a driver? The UX171a is a "power" tube, okay PuppyPower (thanks Jim..). Having spoken to some people who were into this, they said that to hear a "real" driver, a power tube with minimum 2Watts of power is to be used... Okay, one of my all-time favourites is the '45'.. Looking into my poweramp at the powertrannie, I had (amongst others) a 150V tap open... Since the used Lundahl LL1660 can see only 20mA I decided to give it a try... The UX171A had a lead-acid battery for the filament which is not feasible here. Fortunatly I also had an open 8V on my filament transformer, so a nice current source, using a well heatsinked LM350T, would do the trick... When using the high voltage tap of 150V the '45' was by far too low in its characteristics... A clear 100Hz humm let me know it wasn't feeling fine.... Sheit What now? The second open highvoltage tap was 275V, that would lift me far above the max 20mA for the Lundahl... Fortunately I had still a Tamura SS-351 lying around... (a loaner..). I decided to go back to the UX171A and mount the SS-351 instead of the Lundahl LL1660, to get used to its (better) sound.. After a couple weeks of listening, I adjusted the power supply to a choke input, using the 275V tap (10He/47mF/10He/47mF). That kept the '45' alive without any humm... Is is a recommend setting from Cunningham, by the way. I now have a B+ of about 260V with a mere 27mA flowing through the '45'. Ican't go any higher since the SS-351 can have 30mA.. But:Listening to a power-driver a definetely opened up my ears! If you want power, and I mean POWER, go for a powertube as driver! If you have a sub or some kind of active low-end reponse - this upgrade can be not that audible... All the others: Go for it!

!!!Nice Nice Nice!!! Last week I got 2 supply chokes from Tribute... These were meant for the upcoming test of supply chokes. They needed to be "burnt in" before entering the arena... Since years I am using the 6-chamber chokes of AE-Europe, and am very pleased with its performances! These Tribute chokes are from another planet, though... Really nice made, good looking potted chokes made from first class materials: C-core, 0,05: 10He/200mA at 77ohms Rdc.. They are wound in 24 layers, each insulated by thick paper, thus creating a "24-chamber" choke!! These are the "normal" chokes from Tribute...As by coincedence they are about the same size as the AE's, so easy to mount.. I am using this choke as "the last" one in the supply for the TJ300B. So that makes: 2mF Oil/10He-200mA AE/47mf WKZ/10He-200mA Tribute/47mF WKZ/VanderVeen 5K... Needless to say that the supply is silent.. Somewhat later I told Tribute that they were mounted and indeed sounding somewhat better than the AE's.. The rest of the day the installation was playing to give them a real burn-in... When I came back to my listening room, about 12 hours later, I really couldn't believe my ears! What was happening here?? Did I mention a mere improvement to Tribute before, the improvement had really evolved to 'major'! My god, how a big of a difference a supply choke can make! More stage (wider and deeper), more power and above all, cleaner, much more cleaner - everything seems to pop out of the black... It is almost stunning to hear what a real difference a good supply choke can make.. I srongly advise anyone to go for good chokes for improvement, before thinking of "better" OPT's or coupling caps!!! Serious!

PS: Not really fair to directly compare the AE's with the Tributes.... The AE's are really good value for money, however can not match the materials used in the Tributes...

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