Thanks for the quick reply. Yes, I am planning similar project. So far, I have the option for 212e, 304tl, 833a, TB3-1000, TB3-2000. while I already have first two tubes, your posts let me rethink my choice on 304tl ( for its very low Rp, very easy to drive, but not sure its sound ). What will you recommend among the 5 tubes?
Good morning Jerrymouse,
all your mentioned tubes are contenders of a serious amplifier. I have to admit i've never heared a 212 before....so i can not comment on that triode.
The 304TL; very nice......but is essence it is nothing more than 4 parallel tube-systems in a single glass enveloppe. So essentially you can also built an amplifier with 4 x 75TL (difficult to source) or 4 x 100TH (easy to obtain). If the whole idea is to get a poweramplifier with a single output device; than this is kind of cheating. But.....the 304TL does sound nice.
Easy to obtain; prices steadily going higher for there is no current manufactorer.
833A: very easy to obtain. Reasonable priced. When properly driven GREAT results (i started my amp with this triode ....no regrets). And you have options too.....changing from metal anode to carbon anode. And even change to Russian equivalents (which really does sound different).
TB3/1000 and 3/2000: available ? WHERE.....please let me know where i can stash up my stock. Serious good....but i would never build with these beauties if i didn't have enough spare. As for the 3/2000.....this is a HUGE tube. My collegue is building an amplifier with them. It dwarves my 330 kgs TB3/1000 amplifier by at least a factor of 2 ! (included pictures of a Westinghouse 833A compared to the TB3/1000 and the TB3/2000).
So it is not a question of taste....but a question of availability. If i have the choice....i first have to hear a proper 212 amplifier. So i can comment on all 5. If the choice is 304TL, 833A, TB3/1000 or TB3/2000: TB3/1000 !
Why:
- 304TL is not a proper single tube
- 833A would be my second choice because of the availability
- TB3/2000....what on earth do you use as speaker ?
Hope this helps ?
Reinout
all your mentioned tubes are contenders of a serious amplifier. I have to admit i've never heared a 212 before....so i can not comment on that triode.
The 304TL; very nice......but is essence it is nothing more than 4 parallel tube-systems in a single glass enveloppe. So essentially you can also built an amplifier with 4 x 75TL (difficult to source) or 4 x 100TH (easy to obtain). If the whole idea is to get a poweramplifier with a single output device; than this is kind of cheating. But.....the 304TL does sound nice.
Easy to obtain; prices steadily going higher for there is no current manufactorer.
833A: very easy to obtain. Reasonable priced. When properly driven GREAT results (i started my amp with this triode ....no regrets). And you have options too.....changing from metal anode to carbon anode. And even change to Russian equivalents (which really does sound different).
TB3/1000 and 3/2000: available ? WHERE.....please let me know where i can stash up my stock. Serious good....but i would never build with these beauties if i didn't have enough spare. As for the 3/2000.....this is a HUGE tube. My collegue is building an amplifier with them. It dwarves my 330 kgs TB3/1000 amplifier by at least a factor of 2 ! (included pictures of a Westinghouse 833A compared to the TB3/1000 and the TB3/2000).
So it is not a question of taste....but a question of availability. If i have the choice....i first have to hear a proper 212 amplifier. So i can comment on all 5. If the choice is 304TL, 833A, TB3/1000 or TB3/2000: TB3/1000 !
Why:
- 304TL is not a proper single tube
- 833A would be my second choice because of the availability
- TB3/2000....what on earth do you use as speaker ?
Hope this helps ?
Reinout
Attachments
I have recently built one pair of amplifier using RCA833A as the power tube. The output transformer was specially made in Japan with cathode feed-back winding. The working voltage is about 980V and the current about 140mA. The original circuit use two parallel connected 6EM7 as the driver, driving the 833A tube through a interstage transformer (also specially made in Japan) having a ratio of 1:0.8, the triode section of one 6EM7 use as the first stage driver. The result is quite alright and the size of the amps are acceptable (about 330mmx430mm and weighting 35kg each).
I have modified the circuit in the past few days using 2A3 as the driver and 6J5 in the first stage. The sound quality is much improved though the overall gain is less requiring a driving voltage of about 2.5V for full power output (about 60W). I may increase the output power by applying a positive bias voltage and increase the working current to 180-200mA, but I think that the power transformer will become too hot and I may not get enough driving power from the 2A3 and 6J5 combination. I may put an input transformer before the first stage but I wonder if it will do any good. I may try to replace the 6J5 with the WE437A to get more gain but in that case I shall need to enlarge the socket hole in order to put the 9-pin special socket (made by Yamamoto, good but very expensive). I may even try the WE417A which is smaller but with similar gain as the WE437A. It is much cheaper and I have got a few pieces of them. The WE437A shall be used on the mono amps that I plan to use the 300B as the output tube. One friend of mine bought a pair of WE 91 reissue power amps direct from WE and they sound really nice. I shall try to duplicate the circuit and see how it sounds using my irons on hand.
I have modified the circuit in the past few days using 2A3 as the driver and 6J5 in the first stage. The sound quality is much improved though the overall gain is less requiring a driving voltage of about 2.5V for full power output (about 60W). I may increase the output power by applying a positive bias voltage and increase the working current to 180-200mA, but I think that the power transformer will become too hot and I may not get enough driving power from the 2A3 and 6J5 combination. I may put an input transformer before the first stage but I wonder if it will do any good. I may try to replace the 6J5 with the WE437A to get more gain but in that case I shall need to enlarge the socket hole in order to put the 9-pin special socket (made by Yamamoto, good but very expensive). I may even try the WE417A which is smaller but with similar gain as the WE437A. It is much cheaper and I have got a few pieces of them. The WE437A shall be used on the mono amps that I plan to use the 300B as the output tube. One friend of mine bought a pair of WE 91 reissue power amps direct from WE and they sound really nice. I shall try to duplicate the circuit and see how it sounds using my irons on hand.
Hello Reinoutdv ,
Just back from a long overseas trip. I checked Ciel they still got TB3/1000 and bought 18 tubes. They arrived safely. Yes, you are right, TB3/1000 is way better built than 833A. A technical question need your help: at 800V plate voltage and +20v grid voltage, how much will be the grid current?
Just back from a long overseas trip. I checked Ciel they still got TB3/1000 and bought 18 tubes. They arrived safely. Yes, you are right, TB3/1000 is way better built than 833A. A technical question need your help: at 800V plate voltage and +20v grid voltage, how much will be the grid current?
Good evening Jerry,
you did a great buy ! Not cheap...but worth it !
May i suggest to print out the THREE (3 !) different TB 3/1000 datasheets on Frank's site( electron Tube Data sheets - T ). You will find at the .de datasheet (the middle one) a very usable sheet for your question:
800V - 20V at the grid......350 mA anodecurrent.
Succes with the building and if you need funny Caddock resistors (+1000V; non-inductive) ...maybe i can be of assistance.
Regards, Reinout
you did a great buy ! Not cheap...but worth it !
May i suggest to print out the THREE (3 !) different TB 3/1000 datasheets on Frank's site( electron Tube Data sheets - T ). You will find at the .de datasheet (the middle one) a very usable sheet for your question:
800V - 20V at the grid......350 mA anodecurrent.
Succes with the building and if you need funny Caddock resistors (+1000V; non-inductive) ...maybe i can be of assistance.
Regards, Reinout
Good afternoon Reinoutdv ,
I got the German version datasheet, very linear curves. But I can not find the grid current under +20v grid voltage. This is for design purpose ( drive stage). I am considering 2300v plate voltage 10k load so that it can output A1 50w. If driving into A2( +20v), it can provide 100w. Any experience to share on the load impedence selection ?
I got the German version datasheet, very linear curves. But I can not find the grid current under +20v grid voltage. This is for design purpose ( drive stage). I am considering 2300v plate voltage 10k load so that it can output A1 50w. If driving into A2( +20v), it can provide 100w. Any experience to share on the load impedence selection ?
Good evening Jerrymouse,
maybe i am completely wrong but at those settings the anodedissipation must be 2300 V x 650 mA = 1495 W. But the max allowable is onmly 500 W. So i think this setting will be really hot ?!
Back to your questiona about the gridcurrent with the setting 800V / +20V grid: this will be less then 0,1 amperes.
1. check the first datasheet at Frank's site page 3: there's a Class A sheet: 3000 V.....~~ almost no milliamperes at the grid. So please let this signal really be low in impendance.
2. check a sheet of constant current characteristics of something similar like the 833a: same result: waaaaaay less then 0,1 gridamperes.
Loadlines: again the 833a is the easy example:
- 3 kV / 20K / 100 mA
- 2 kV / 10K / 150 mA
- 1,5 kV / 8K / 200 mA
- 1 kV / 5K / 250 mA
- 650 V / 2K / 290 mA
Currently my TB-3/1000 runs at 1100 V / 5K / 225 mA (approx).
Do you already have a set-up / schematic / plans / breadboard / PICTURES ?
Reinout
maybe i am completely wrong but at those settings the anodedissipation must be 2300 V x 650 mA = 1495 W. But the max allowable is onmly 500 W. So i think this setting will be really hot ?!
Back to your questiona about the gridcurrent with the setting 800V / +20V grid: this will be less then 0,1 amperes.
1. check the first datasheet at Frank's site page 3: there's a Class A sheet: 3000 V.....~~ almost no milliamperes at the grid. So please let this signal really be low in impendance.
2. check a sheet of constant current characteristics of something similar like the 833a: same result: waaaaaay less then 0,1 gridamperes.
Loadlines: again the 833a is the easy example:
- 3 kV / 20K / 100 mA
- 2 kV / 10K / 150 mA
- 1,5 kV / 8K / 200 mA
- 1 kV / 5K / 250 mA
- 650 V / 2K / 290 mA
Currently my TB-3/1000 runs at 1100 V / 5K / 225 mA (approx).
Do you already have a set-up / schematic / plans / breadboard / PICTURES ?
Reinout
Good morning Reinout,
Thanks for the ideas. at Vg =-40v Va=2300v, plate current is about 200mA, only 460w. For your working point, RL=5k , is it too low as Ri is about 4K? Do you measure the distortion of your amp? I am still in planning stage but collected all components except for output transformer which seems that I have to diy. If I finally decide to go for A1, then it will be a simple two stage amp, driven by choke loaded 437a, 417A or D3A. But if go for A2, seems that a least three stage is needed.
Regards
Thanks for the ideas. at Vg =-40v Va=2300v, plate current is about 200mA, only 460w. For your working point, RL=5k , is it too low as Ri is about 4K? Do you measure the distortion of your amp? I am still in planning stage but collected all components except for output transformer which seems that I have to diy. If I finally decide to go for A1, then it will be a simple two stage amp, driven by choke loaded 437a, 417A or D3A. But if go for A2, seems that a least three stage is needed.
Regards
hi, which store was that? any links? i have friends in singapore who i can ask to buy for me....
I think he was referring to: TB3-1000 - Triode - - ELECTRONICS TUBES - TRANSMITTER POWER TUBES
I saw on the internet some amplifiers that use 833 A, C tubes.
Two examples would be Wavac SH-833 and Amplifon SET140.
If they are mass-produced, even if limited, it is assumed that there is a manufacturer of such tubes.
Does anyone know what final tubes the two companies use? Who are the tube manufacturers?
Two examples would be Wavac SH-833 and Amplifon SET140.
If they are mass-produced, even if limited, it is assumed that there is a manufacturer of such tubes.
Does anyone know what final tubes the two companies use? Who are the tube manufacturers?
Sorry to barge in, but I have a couple of 8000 tubes, and was wondering if they have any potential use? It looked from the tube data sheet that they could work with 600V on the plate and 1000R load, but then I realised how much heat was involved when I saw the plate current would be around 400mA!
It would be too much of a project for me, but interested if they could be harnessed.
It would be too much of a project for me, but interested if they could be harnessed.
