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Everything posted by pmcuk

  1. That's a very nice 2a3 amp! Can you post the schematic?
  2. That's a similar theory to "you should always put your amps on top of your speakers - that way the electrons find it easier to drop down into the voice coils"
  3. I think "Dunker Factor" is worth mention. " In the early to mid 1990s the Norwegian "boat anchor" valve amplifier constructor Thomas Dunker published some groundbreaking essays on how to replace the famous unsinkable "Norwegian Wood" with left over NATO boat anchors, or failing that by massive valve amps. A measuring unit, the Infamous Dunker Factor was named after him by fellow audiophiles. The Dunker Factor defines the sink rate (m/sec) proportional to the amplifiers weight/output ratio (t/mW). So a Dunker Factor of 1 says that 1 amp of 1000kg and 1000 mW will sink at 1 meter/second. Following his example, constructors of valve amps strive for a Dunker factor of 1. This can be achieved with an amplifier of 1,000kg which can produce 1 Watt into their speakers."
  4. I'm the one that's Welsh! From Bridgend, Glam. There you are, then.
  5. I bet you have an amp that goes up to 11 and enjoy playing in D minor, the saddest of all keys.....
  6. Another experience comes to mind from the 1970s. Me and the drummer in our band were looking for a cheap stage amp, and so we went into the local junk shop (yes, these used to exist) to have a look at what they had. The guy at the counter had a rummage round and with a wide smile hauled a scruffy old amp onto the counter for us to have a look. Conversation went... Guy: "You'll like this one boys. It's a goodun." Us: "So how much power does it have?" Guy: "Ah, you'll be fine with this one, boys. Says on the back it gives out a full 8 ohms!"
  7. If you're free on Sunday we could have a dribbling contest and read Jabberwocky.....
  8. Hopefully we can have some fun with this thread! Delusional is a word commonly associated with cables and oak feet, but it goes much further than that. So can you think of any mind twisting exeriences in your audio history? My contribution is that after days of doing calculations for a new amplifier circuit, I wake up in the night trying to apply Ohms Law to sleep. I try to determine how many hours I need to sleep in relation to the current involved in the sleeping process....... Yes, doctor, I'll come quietly.
  9. Drastic price reduction to £570. This is as low as I can go. Advertised elsewhere.
  10. Ahhhh..... vintage. Wonderful. In my case tubes from the 1920s and 1930s before the Americans came along and standardised on 9 pin and octal sockets and 6.3v filaments. I love all the old European sockets and all the old 4v and 13v radio tubes, and I have quite a collection of them. All the rest of the components are pretty fresh - not into old capacitors and resistors!!!
  11. I think that's an unnecessary demand. I've regularly used 89db down to 86db speakers at lower volumes in a medium/small room without issues, and bass hasn't been a problem. I'm not quite clear about what your priorities are as a listener, since you remain unsatisfied. Mine are transparency and timbre, and of course the timbre on voices and acoustic instruments is generally accepted as anywhere between very good and magical with well designed 300b SEs.
  12. I was lucky enough to hear a Lamm 6C33C SE amp at one of the shows. It was wonderful. That's a clever design from a guy who understood Russian tubes. From what I understand, though, quality control on the 6C33C was pretty variable - they measured all over the place. As with a lot of Russian tubes, a lot were made for the military and they turn up anywhere these days, including presumably some non-premium ones. Mind, quality control on most Russian tubes was pretty good.
  13. That's not what I'm getting from my 300b SE amps. Nothing slow and soggy - on the contrary, my amps are exceptionally clean and clear, but I've been optimising the designs for 12 years. No "slow and soggy" input tubes here like 12AX7 etc. and the input tube matters hugely. Yes, of course, if you want power and current look elsewhere - no disagreement there. But a lot of audiophiles listen at lower volumes in smaller rooms. And frequency response shouldn't really be a big issue. If it were there would be a lot less 300b amps around than there actually are.
  14. Try it? Should work.
  15. Why? I've found 300b SE amps very easy on speakers - most of them sound good to me, including bookshelf speakers.
  16. You'd be surprised how good bookshelf speakers can sound with a 300b SE amp, which is what I use. I originally used Alpair 10M in tall columns but half-heartedly tried out some old and cheap Wharfdale bookshelves I was going to sell, and they're still in there! I'd be considering some of the nicer bookshelves - they are good for midrange and treble, which is where the 300b's strengths lie. I find the bass is OK as well - tidy and just enough unless bass is critical. I can live with it contentedly, and I'm a bass player! Bearing in mind that the cobbler's children have no shoes.......
  17. As Jazid says - 5Z3 is a sleeper. I can see me changing one of my PSUs over to a UX4 base. I'm a bit in love with the Sylvania VT-244 and it should sound the same with a UX4 base. The piano tone is wonderful, but it's good in general. I'm listening to Keith Jarrett and it's just totally lovely. Anyway, here's the final group of rectifiers - the 5R4 types. 5R4GY JAN CRC - the best of the four I tested by a whisker. The 5R4 drops more volts, though I didn't measure that. The 5R4 family are generally smooth and softer than the 5U4 family, with softer treble and bass. The piano was more rounded without the silvery Steinway tone on the VT-244. Voices were nice, and it was quite holographic. But after the clarity of the VT-244 it's a step down. 5R4GYA Hewlett Packard and 5R4GA Philips. These were straight bottles. Mostly like the JAN CRC, same softer tone and fairly holographic with good voices but the rounded piano tone. 5R4GY RCA Disappointing. Sound was flat and voices bland. A step down from the other three and really not very interesting or involving. General conclusion is that the VT-244 is the one staying on, to be joined by some 5Z3. The 53KU, Cossor GZ33 and Sovtek GZ34 were also good and maybe the 5C3S slightly behind them. But the Sylvania VT-244 takes the cake. It's not cheap these days, and it's no secret amongst audiophiles. Before you get the itch to roll your GZ34s, just a reminder that the GZ34 is a 1.9 amp tube and the 5U4 is a 3 amp tube - more stress on the transformer. .
  18. I retested the 3A tubes with another power supply and updated my impressions. Top Group 53KU, 5U4 GE, VT-244 Sylvania, GZ33 Cossor, Not quite top group 5U4 Philips, 5U4 Mullard, 5U4G Sovtek, 5C3S, Second group 5V3A, 5V4G I was pleased to find that the VT-244 Sylvania, which is a £40 tube, is identical to a Sylvania 5Z3 and also a VT-145 Sylvania, the only difference being the 5Z3 has a UX4 base. Same construction with long ribbed plates. Since the VT-244 is as good as any of these tubes and right at the top of the list, that's worth knowing.
  19. Not quite sure what you mean here, so just emailed you. I've been listening to the 5Z3 and really enjoying it. I have another 4 which have UX4 bases. I'd have to swap bases to try them, but I'm getting curious. I have a large box full of rectifiers and it was high time to try them out. As you say, rectifiers can make an audible difference to the sound. I had a closer look at my octal "5Z3PA" and it's a rebadged Russian 5C3S. Still sounds great in this particular amp.
  20. I've been building power supplies for my 300b amps, and having built three PSUs I thought I'd do some rectifier tube rolling. Results were interesting. No dramatic differences, to put it in context, but some subtle differences which I found were audible. The 300b SE I used has NP Acoustics amorphous 3.5K output transformers, so a good quality setup. I was intending to sell this particular amp, but having heard some good results with rectifiers that suit it I'm not so sure. The amorphous OPTs are clean and clear with good detail, and my findings were that they responded best to slightly warmer and fuller sounding rectifiers. Hence these were included in my top group, and a second group of rectifiers which were predominantly cooler in sound didn't seem to have the same synergy, though could be OK elsewhere. So here's my impressions. Music was Wagner Gotterdammerung last act, Janacek Cunning Little Vixen, Steely Dan Negative Girl and Bill Evans Quiet Light. The HT voltage varied a little and is included with each. Top Group 53KU (CV378) 2.8A, 352v Very nice, involving, smooth, clear. A keeper. 5C3S Russian (marked 5Z3PA) 3A, 340v Smooth and nice, very easy to listen to. Piano was slightly softer compared to Edicron GZ34. Voices were full and nice. Very punchy bass. GZ34 Edicron 2A, 355v Good. Clear and clean, involving. Nice piano sound. Edicron is a rebadged Sovtek. GZ33 Cossor 2.8A, 370v Clear and clean. Neutral, not warm or flat. Balanced. Nice piano sound. Second Group 5U4 Mullard 3A, 350v Clear and clean, bit somewhat flat. Less involving than the others. More 2 dimensional. Less fine detail. 5V4G Brimar 2A, 362v Clear and clean, bit somewhat flat. Less involving than the others. More 2 dimensional. Quite nice piano sound. 5V3A RCA 3A, 349v Clear and clean, bit somewhat flat. Less involving than the others. More 2 dimensional Comments I specially liked the 53KU, which was tied up in brown tape because of a loose base but still shone. The 5C3S was similar - a fairly cheap Russian tube made e.g. by Svetlana. The Edicron GZ34 was a lighter and clean sound, but remained involving to listen to and had excellent piano tone. This is a rebadged Sovtek, which always gets good reviews and is very good value. The Cossor GZ33 was neutral and a very "correct" sound but I slightly preferred the three mentioned above. The second group didn't suit this particular amp, but may suit other amps better. I also tried another power supply with 2xAZ1 mesh rectifiers and while this was very detailed, it was again a cooler sound. I use this with my O-Netics 300b SE amps, where the OPTs have a warmer and fuller tone. I'd be interested to hear any other rectifier rolling impressions. It's an interesting way of tuning an amplifier. Be aware, though, of the different current requirements of the various types. If you have an amp specced for a 2 amp GZ34 then your transformer may not take kindly to the 3A rectifier tubes, and I certainly wouldn't risk a 3.8 amp rectifier like the 5V3 or 5AU4. I have some of these but didn't try them for that reason. .
  21. Hello Steve Sorry to be a bit late responding. I have a pair of 125GSE OPTs which could be configured for various ratios including 10K. Quite big and heavy - 25 watts SE. PM me if interested. Andy https://www.hammfg.com/files/parts/pdf/125GSE.pdf
  22. pmcuk

    45 SET amp

    I'm knocked out by this simple yet highly effective build. Lovely chassis, great design. And I'm not surprised it sounds good. When you spend many, many solitary hours building amplifiers It's good to get really positive feedback, isn't it? I mean, nobody keeps you company in this lighthouse-like existence, except for some music or the news in the background. It's enough to turn extraverts into introverts!
  23. This is really interesting - the beat is regular but the harmonies are off beat, making it sound as if the bars are irregular, which they actually aren't. Clever and sounds excellent. I like this track. The vocals are clearer too. This guy is making good progress in his musical career.
  24. I really should look into this. My GP said my L ear was full of wax. She recommended putting olive oil in it......??
  25. I'm forging on with the 300b and 2a3 SE amplifiers. Finished 2 power supplies over the weekend. I'm going for around 350v HT. Rectifiers are GZ34 or 2 of AZ1 mesh in the luxury version - love mesh rectifiers. Good size choke, DC Link caps. Really going for nice parts here. I've been listening to a 6C4C output stage for a few days which is really nice. It's a contender for favourite output stage alongside the 300b. I didn't expect it to be this close. The 6C4C is a very affordable Russian equivalent to a 6B4G, which is a 2a3 with 6.3v filaments at 1 amp, octal base. I'm going with a 2 chassis design, which keeps the amp small and light enough to handle easily. It's also very flexible in terms of modifying the signal chassis. I'll have a few amps for sale soon. PM me if interested.
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