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Bas are you using your B7 yet?

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Bas,
I don’t know if you have your B7 in use but if not here is an easy suggestion to try. I’m always on the lookout for cheap--filament frugal because I use batteries--directly heated options to swap in my 26 preamp for background listening. Normally 5676, 958A, 1LE3 are wired up on four-pin sockets and get plugged in. I recently tried a Russian 1Ж17Б aka 1J17B aka 1SH17B (the 1J24B is not as good) DH pentode with G2 and G3 wired to the plate. Better sound then 5676, so I thought I’d work up a breadboard using it and the B7. The tubes are a dollar or so, very minimal investment, and their 1.2V/.045 filament lasts a long time on a D cell. I’m using 5 12V SLA batteries for B+. I have no curves on the 1J17B, but it sounds much better with plate chokes over 200Hs, hence my choices. Surprising sound, just a thought.
Matt

Follow Ups:

RE: Bas are you using your B7 yet? - Dyna Saur 08:15:38 03/05/08 (6)
Tube curves here:
http://istok2.com/data/?mmm=158
The cyrillic letter Ж is pronounced as "zh" and could be used to approximate either a J or Z sound. The tube is listed in some places as a 1Z17B rather than 1J17B.
Da, Tovarisch, it's in Russian, but then that's about all I Could find.
I'll try a basic translation, however my Russian language skills aren't all that great ;-) I just know enough to get into trouble ...
/ed B in NH
real radios glow in the dark
- 1Ж17Б Параметры и характер (Open in New Window)
Edits: 03/05/08 03/05/08 03/05/08 03/05/08
- RE: Bas are you using your B7 yet? - Dyna Saur 09:06:26 03/05/08 (5)
  1J17B (or better, 1Z17B) Operating Characteristics:
  (These translations may not be perfect, it's off the top of my head)
  Pin connections of Tube 1Z17B:
  a: package outline
  b: pinout of the tube's base
  c: schematic diagram of the tube
  1: Cathode / filament
  2: Cathode / filament
  3: internal shield
  4: third grid (suppressor grid)
  5: second grid (screen grid)
  6: first grid (input grid)
  A: Anode - (plate pin on top of tube)
  Bulb length 40 mm (1 5/8 inch)
  Lead lengths at least 40 mm (1 5/8 inch)
  Lead diameter 0.4 mm (1/64 inch)
  Anode lead length 25 mm (1 inch)
  Input capacitances:
  
  Input 3.7 +/- .7 pF
  Output 2.7 +/- .4 pF
  Transfer no greater than 0.05 pF
  Anode - Cathode: no greater than 0.15 pF
  Filament Voltage 1.2V
  Filament Current 60 +/- 6 mA
  Plate voltage 60V
  Screen Grid voltage 40V
  First Grid voltage 0V
  Plate current 2 mA +/- 0.5 mA
  2nd grid current no greater than 0.25 mA
  Transconductance no less than 1000 uMHOs (1.0 mA/V
  Transconductance with 0.95V filament voltage no less than 850 umhos (0.85 mA/V)
  Grid circuit resistance 60K ohms
  Inverse grid current no greater than 0.5 uA
  Maximum operating conditions
  Maximum filament voltage 1.4V
  Minimum filament voltage 0.95V
  Maximum plate voltage 90V
  Maximum second grid voltage 60V
  Maximum plate dissipation 0.5 Watt
  Maximum second grid dissipation 0.18 Watt
  Maximum cathod current 5 mA
  /ed B in NH (with nothing better to do during lunch hour) ;-)
  
  real radios glow in the dark
  
  Edits: 03/05/08 03/05/08 03/05/08
  - RE: Bas are you using your B7 yet? - mwiebe 09:56:51 03/05/08 (4)
    Dyna Saur,
    Thanks for the data page. I remain impressed with the sound of the 1J17B for what it is, but not so with the 1J24B. I still have to socket 1J18B 1Ж18Б, 1J24B 1Ж24Б, 1P24B-V, 1J29B 1Ж29Б and give them a try. I usually pick the name according to how I can find them on Ebay. The directly heated 4P1L, a loktal beam tetrode, is also nice, but lower the voltage on the filament to keep it from ringing.
    Matt
    - RE: Bas are you using your B7 yet? - Dyna Saur 11:52:25 03/07/08 (0)
      I would guess that there is probably a US equivalent of the subminiature 1Z16B, maybe not with the separate anode "cap" pin out the top. These were used in hearing aids, smaller sized tube portable radios, proximity (variable-time) fuzes, and lots more pre-transistor applications. The Russians continued to advance their subminiature tube technology, well after we went to solid state almost exclusively.
      
      With the relatively light 1Z17B's filament current, and only 2 mA or so of plate current, 4 mA total for two channels, a collection of 6 or 7 series-connected 9V batteries would probably last a very long time. And no AC hum problems to fret about... THere are 10 AH NiMH D cells available, perhaps higher current now, I got my D-size (solder tabbed) 10Amp'ers a couple years ago from zbatteries.com
      
      /ed B in NH
      
      /ed B in NH
      real radios glow in the dark
    - vacuum tube archeologist..... - mqracing 12:01:52 03/05/08 (2)
      Hi Matt:
      
      no longer will I think of you as a writer--- not after your posts and finds!!!
      
      are their any american made directly heated pentodes (small signal)?
      
      do you have any photos of these tubes mounted/installed? I can't picture how your mounting these.
      
      and they sound good???
      
      MSL
      - 1S4 and 3S4 (Tungsol) DHT pentodes were used in radios... - Mike Spence 18:00:56 03/05/08 (0)
        
        In Reply to: RE: vacuum tube archeologist..... posted by mqracing on March 05, 2008 at 12:01:52
        
        3S4 makes a great low-power guitar amp tube!
        
        Mike
        3S4 DHT pentode (Open in New Window)
      - RE: vacuum tube archeologist..... - mwiebe 14:09:59 03/05/08 (0)
        
        In Reply to: RE: vacuum tube archeologist..... posted by mqracing on March 05, 2008 at 12:01:52
        
        Mike,
        I don’t think the 26 or thoriated filament tubes are quaking in their boots. I’m just looking for filament frugal tubes that sound good. I still use battery filaments/B+ so longer play before recharging colors my opinion. I need to get other ears to hear the 1J17B, but it sounds good to me.
        
        In North America, there are sub-minature DHTs like 1D3, 5676, 6029, 6286 and the directly heated beam tetrodes like 1AG4, 512AX, 6088, 548DX, 6519, 6611, sound nice trioded. According to data books there are a few more but they are not easy to find like the above.
        
        I’ve not found any sub-miniature Russian DHTs so that is why I’ve been looking at DH pentodes. The Russian tubes are just a little bit cheaper on average, even including shipping, which is why I’m looking there.
        
        I would like to get a B7 preamp inside a box no larger then a thick paperback, including batteries for B+ and filaments, for no other reason then it sounds fun.
        Matt
Not using the B7's yet unfortunately...but it is the next project - Bas Horneman 04:29:38 03/05/08 (1)
I'll do that is for sure. And just like you I want to try a couple of tubes. I might just get me some 1j17B. Where did you get them by the way?

Regards,
Bas
To infinity and beyond!!!
- RE: Not using the B7's yet unfortunately...but it is the next project - mwiebe 06:57:59 03/05/08 (0)
  Bas,
  A 4-pin socket, or octal, with wires ending in alligator clips makes swapping between acorns and sub-miniatures easy. I’ve linked an Ebay 1J17B auction below. “Urals” seems to offer 10 1J17B at random prices but since they are being sold by the 100 count, I expect there is plenty of stock.
  Matt
  - Ebay 1J17B (Open in New Window)
RE: Bas are you using your B7 yet? - Hank Murrow 16:16:26 03/04/08 (0)
Dear Matt;

Your schematic interested me, and when I tried to move it to my desktop, it would not open. Guess I will look around for a cocktail napkin! Nice idea.

Cheers, Hank

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