After reading Slajeunes experiments with 12V tubes I ordered a handful of russian subminiature tubes last week, and finally received them today. Now I need some help, here is a piece of the datasheet (tubes are 1Sh18b):
(http://home.tiscali.de/krabbensaft/1sh18b_dat.gif)
From my *very* limited knowledge of tubes, this are pentodes, right? Can I use these in the Ruby Tuby circuit for example? Because I remember reading somewhere that you can wire pentodes as triodes somehow...?
The cathode/filament calls for 1.2V, is it ok to use a 1.2V battery here and a different power supply (wall wart) for the rest of the circuit?
Any help appreciated!
Hi Spongebob,
interesting tube! Here is pretty much the only schematic that I could find:
http://www.jogis-roehrenbude.de/Leserbriefe/Jochens-2kreiser/Jochen-2kreiser.htm
This site seems to have a lot of low voltage tube stuff. Unfortunately, I don't speak german....
For the heaters on a 1.2v battery, it depends on how much current it sucks. If it does suck a bit of current, your battery might die very quickly!
My guess would be that you could use it in a ruby tuby setup. Check out Doug's pentode driver for an example of using pentodes in pedals!
Cheers,
Stephane.
Quote from: slajeuneHere is pretty much the only schematic that I could find:
http://www.jogis-roehrenbude.de/Leserbriefe/Jochens-2kreiser/Jochen-2kreiser.htm
There's an amplifier schematic on the same site which uses 1Sh18B (and 1Sh29B):
http://www.jogis-roehrenbude.de/Leserbriefe/Drehko-Stefan-Miniamp/Miniamp.htm
In the meantime I built the following on stripboard (taken from the schematic shown on the page above):
(http://home.tiscali.de/krabbensaft/1sh18b_test.gif)
I can hear the guitar when I connect the circuit to my lm386 amp, but there's also a loud high-pitched whining tone, looks like I built an oscillator! :wink: The 15V are coming from a switch-mode power supply, but I don't think that should be a problem? The 1.2V for the cathode are coming from a battery, measured current draw is 23mA, that's not too bad. I'll recheck everything tomorrow, maybe it's just a wiring error...
2 Spongebob:
Hi, I'm a newbie in this forum and I'm Russian. Just watched 1Sh18B datasheet, it seems to be high-frequency pentode. Max. plate current is 1.85 mA. I have seen such tubes in older military tranceivers. Why not to try it in some preamp stages :wink: Try it in triode mode. If you need some more datasheet information about this tube I would be glad to translate it to you.
The high-pitched whining tone you mentioned might be an osscilation :( Try to put 1nF capasitor in parallel to plate resistor.
Is 15V plate voltage sufficient for the tube? Normal datasheet value is 60V...
Good luck in your research.
Welcome to the forum @ndy. :D
Spongebob, that oscillation you hear could easily be your switching supply. Try @ndy's suggestion of adding a 1nF cap across the plate resistor. If you don't hear a change in the frequency, chances are very good the supply is the source of the noise.
You could also try connecting the +15V line to the output via a small cap like 10nF. If the sound is in the power supply, that should show it to you.
Best of luck!
-Peter
Hi Andy,Welcome to the Forum.
JD
You guys should also check out the Nuvistor!
These were used in some old Ampex preamps. They’re pretty cool.
Nuvistor (http://www.thevalvepage.com/valvetek/Nuvistor/nuvistor.htm)
Also see;
http://semiconductormuseum.com/OralHistory/RCA/Mendelson/Mendelson_Index.htm
http://www.logwell.com/tech/components/nuvistors.html
http://hhscott.com/cc/nuvistors.htm
Hooray, it works! I replaced the power supply with two 9V blocks (18V) and the oscillation is gone. Looks like the switch-mode supply was causing the trouble. Output is now loud and clear (no distortion yet :wink:), really amazing for a battery operated tube! I also tried using a single 9V battery, but the output level went down drastically.
My DMM shows only a very small current consumption on the two 9V batteries, like 0,06 mA, is this possible? If this is true, one could very well construct a battery-operated tube pedal... Did I mention that this tube is cheaper than a JFET transistor? :lol:
@ndy: Welcome, and thanks for your help. I used babelfish.altavista.com to translate single words of the datasheet, for example I now know that aнoдe = anode, напряжение = voltage and Ток = current :) Can you post a few of the other cyrillic words (and their english translation) that appear on this datasheet for example?
(http://home.tiscali.de/krabbensaft/1SH18B-2.gif)
Thanks a lot!
yes switching PS can be a PITA, if you`re not aware of it - especially when dealing with clocked FX.
better to always put some xtra filtering between PS and FX.
Yes, HT current consumption will be very low, and a couple of PP3 batteries will last a long time. Filament supply is the opposite; use a big D-size cell, or possibly even two in parallel. You'll be changing the filament battery several times in the lifetime of the 'HT' supply.
Hi again!
I tried to translate some words as you've requested:
(http://valvesound.narod.ru/vocabulary.gif)
Sorry, I don't know all the special tube terms in English (like this S-value), but please ask if something is needed to be explained :)
Andrei
Heh... The picture is loading a bit too slowly :(
Hi All,
here is another link to a datasheet for this little tube (with loadlines!!!):
http://klausmobile.narod.ru/td/data/_1j18b.GIF
Steph.
spongebob:
Inspired by your idea of experimenting with micro tubes, I searched for some concerning information in russian-languaged internet. Such tubes seem to be a favourite choise of Hi-End guru. Russian DIYers make low noise Hi-End DACs using pentodes of series 1sh... in triode mode. They call this series one of the most noiseless in the world. The disadvantage is that we have to insulate such tubes from vibration, because their filaments have their mechanical resonance somewhere close to 2kHz and there is a risk of microphonic effect.
I have couple of 1sh29b and will try to experiment too :)
Andrei
Andrei, thank you very much for the translations!
Quote from: @ndyRussian DIYers make low noise Hi-End DACs using pentodes of series 1sh... in triode mode.
What do you mean by triode mode? I have read this a couple of times elsewhere, how can I use a pentode as a triode?
I also got four 1Sh24b, they look identical to the 1Sh18b but have two more connections, one for the screen and one for the top grid I think...
Is it ok to increase the anode resistor to get the voltage at the anode down? Because with the 47K resistor (see above), the output at the anode measures around 13V (with 18V supply voltage), doesn't that seem a little bit too high? I replaced the resistor with a pot and found that the voltage drops to 9V with a resistance of 300k. Is this approach ok?
When building an overdrive pedal with these tubes, I don't think two stages have enough gain for some serious distortion, maybe putting a JFET gain stage in front of it would be a good idea? Something like this:
Jfet stage -> Tube Stage -> Volume Pot (Gain) -> Tube Stage -> Volume Pot :?:
Thanks for all the help!
Jan
triode-mode:
screen-grid tied to plate;
i.e.: screen grid directly connected to the anode,
instead of an extra fixed HT (or OT-tap).
gives less power, but more warmth...
Here's a link that covers using the 1SH29B in single ended 12V and uses a 320 ohm resistor to ballast the filament.
http://www.midnightscience.com/_pdffiles/aren%20van%20waarde%20may%202003.pdf
It also mentions the use of a 220V -> 9V 2.4VA transformer as an output transformer. ;) I've heard different things about the results of this approach esp. when it comes to bass but at such a small wattage maybe things don't matter as much.
More stuff here: http://www.b-kainka.de/roehren/roehren2.htm
Does anybody know where these tubes can be purchased in the west?
Thanks!
-Peter
maybe smallbear can get some? :wink:
try searching ebay. they have a butt load of subminiatures i recently got some for a mini plexi i am doing.
http://search.ebay.com/subminiature-tubes_W0QQsokeywordredirectZ1QQfromZR8
http://www.wps.com/archives/tube-datasheets/Datasheets/Raytheon-SP-7073-360-20M/2.JPG
this is a nice little datasheet to print out and keep for your bench so if you spy some cool tubes you can snatch them up.
(http://www.wps.com/archives/tube-datasheets/Datasheets/Raytheon-SP-7073-360-20M/2.JPG)
Quote from: Mr.HugeYou guys should also check out the Nuvistor!
These were used in some old Ampex preamps. They’re pretty cool.
... keep an eye on the last generation tube-based 200Mhz Tektronik scopes ... the front-end preamps where all nuvistor based and built on Silver plated chassis with space age materials used for damping ... fun to turn these into phono preamps ... the Nuvistors used there were hand picked so you can bet they had better than average microphonic specs ...
Quote
Is it ok to increase the anode resistor to get the voltage at the anode down? Because with the 47K resistor (see above), the output at the anode measures around 13V (with 18V supply voltage), doesn't that seem a little bit too high? I replaced the resistor with a pot and found that the voltage drops to 9V with a resistance of 300k. Is this approach ok?
I think plate resistor has to be defined by the maximum allowed plate current for each particular tube. When the tube is fully "open" the current (defined by plate resistor according to Mr. Ohm law) shouldn't exceed allowed maximum. Why do you try to decrease the plate voltage? I think it's not a problem if you have 13V with 18V power supply.
Quote
When building an overdrive pedal with these tubes, I don't think two stages have enough gain for some serious distortion, maybe putting a JFET gain stage in front of it would be a good idea? Something like this:
Jfet stage -> Tube Stage -> Volume Pot (Gain) -> Tube Stage -> Volume Pot
IMHO, number of tube stages depends on the sound you want. Even two stages provide enough gain for some serious signal clipping, but personaly I don't like the sound in this case: it's too cracky. I prefer more stages when each stage just slightly overdrive the sound, adding mostly even harmonics. After each stage there should be tone forming circuit and resistor divider decreasing the amplitude of the signal to avoid next stage overclipping.
The preamp structure you offered seems to be OK, but the best way to find the result is an experiment, I think :)
Quote from: @ndyEven two stages provide enough gain for some serious signal clipping, but personaly I don't like the sound in this case: it's too cracky. I prefer more stages when each stage just slightly overdrive the sound, adding mostly even harmonics. After each stage there should be tone forming circuit and resistor divider decreasing the amplitude of the signal to avoid next stage overclipping.
That's an interesting approach, how many stages would you suggest? I guess 4 should be enough?
I tested the two pentode stage idea this weekend, it consists of a JFET gain stage driving two pentodes, with a volume "gain" control between the two pentodes and a low pass filter + volume control at the output. The JFET produces a high enough output signal to overdrive the first tube slightly, the amount of distortion produced by the second tube can be controlled with the potentiometer between the two tubes. It doesn't sound too bad, but nothing spectacular either. I still have to try the pentodes in triode mode next...
Here's a picture of the board:
(http://home.tiscali.de/krabbensaft/1sh18b_circuit.jpg)
That looks great Spongebob! 8) 8) 8)
How is the clean tone?
Take care,
-Peter
Nice picture Spongebob!
Personally I didn't try to overdrive pentodes in preamp, only power ones in output stages. All I said in previous topic concerns triodes (like 12AX7). But such small tubes like 1sh18b may be excellent to make tube preamp in small stompbox envelope :)
Andrei
2 Spongebob
Quote
how many stages would you suggest? I guess 4 should be enough?
Look at most tube preamps schematics (like MESA, Marshall etc). There are 3-5 stages in most cases. It depends on tubes type, the sound you want to get and other things.
As to me, I haven't made any solid state FX box yet (maybe later :) ). Tubes are amazing!
Yesterday night I have made 1 stage with 1sh29b (similar to Spongebob's but in triode mode) and tested it. A kind of usual tube sound, nothing special. One thing disappoints me: the tube is "microphoning" even when I put my combo to a low volume. It seems the only advantage of 1sh29b is low plate/heater voltages (and small size surely) :cry:
hi all,
this thread seemed to have dried out on a negative note. maybe not all minitubes are so unusuable? came across some 1sh18 1sh17 and 1sh24s. Is anybody still experimenting with this?
Should be possible to put them to some use. There's this hammond tech that has developped a preamp based on these tubes for transistorbased hammonds.
http://www.keyboardpartner.de/hammond/t-mod-skill4.htm
will try out spongebob designs anyway, but later this week.
zj
Wow, this is certainly an ancient thread...quite a resurrection you've managed.
Cool stuff though for sure.
submini tubes aren't good for anything!
8^P
I once read an article about the possibility of using nano-tubes in an IC. Very interesting idea! They were talking about processor chips though, not audio... but imagine the possibility of an all tube opamp... in an 8 pin DIP(or SMT) package!