"Superfly" - submini tube version of Doug H's Firefly

[mrsmash23]

Thank you for helping me! I will try to adjust values of mentioned parts and hopefully find the sweet spot

Level of distortion -> I was going for similar (maybe a little bit higher) level as with 6112 + 6021 combo. First I used 2x lower gain 6N16B-V. Then I realized I need higher gain tube in preamp, but even with 6N17B-V in preamp section, amp is clean sounding with original parts. So to achieve similar level of cruch, I will need to experiment, I'll let you know!

[mrsmash23]

Hello! I tried few combinations of resistor/caps as adviced. Finally, the crunch is here and feels similar to the one with 6112+6021 and original parts.
Parts I have changed with russian tubes:
------
R2: 1,5k
R3: 470r
R12: 220k
R13: 120k
C1: 1uF electrolytic
---
Although it is not the only possible combination. Crunch is present with R2=1,8k (but under 1,5k amp started to squeel), R3=560r, R12=180k and R13=100k. I tried these values as 2nd try, for the 3rd try I tried to go higher(/lower) with values to see if the crunch gets any higher, but I guess the sound didn't get dirtier...

BRYMUS: "If you could add a cathode follower at the end of the pre amp feeding a tonestack/or not that would add some compression of the signal." If you have time and mood to draw your suggestion, I'd like to try it! (You can find schematics with tone stack on page 7). 

OT: Sorry, can't see EDIT button...

[Brymus]

I am glad that worked for you!

Did you use pots on the cathodes to find the best values or did you swap resistors?
(the idea for using pots comes from Merlin's book on building valve pre amps)
http://www.valvewizard.co.uk/

Here is some very good info about the type of CF I am talking about.
http://www.valvewizard.co.uk/dccf.html

Yes I will draw a schematic - it will have to be hand drawn though,not as pretty as the chart you made.

I will also post the data sheet of the Russian tubes I have,maybe you can help me decide what they best cross reference to?
(I believe they are sub mini pentodes,IDK it's been awhile since I even looked at them)

[Brymus]

Here is what I am talking about,since you need another double triode you might as well use the other half and parallel the input stage for less noise and more dynamics.
I love the sound of a two parallel triodes with separate cathode resistors.
IDK if the tonestack will sound the same,I usually use a TMB tonestack,you would still get compression from the CF even if it just fed the output stage.
Or with an extra double triode you could have an extra gain stage too,a lot of possibilities. A bit more work and more current draw,more chance of added noise,ect.

Since getting Merlin's book I am going to mod the stuffing out of my last build which was a Marshall Plexi Super Lead.
Anyway:
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=50866&g2_serialNumber=1

[Brymus]

Here is the data sheet from the sub mini tubes I bought a few years back,I can't even remember what they were called 
There must of been a reason I bought them though,I know for a sub mini tube amp,but thats it.
I do recall they were from MIG fighter plane controls thats it.
If anyone can translate these I would be very happy!!!


I remember someone else used them to make a fuzz circuit for his hammond organ,so they should be usable...

[Zapp Brannigan]

If anyone can translate these I would be very happy!!!


I remember someone else used them to make a fuzz circuit for his hammond organ,so they should be usable...

It's easy - 1ZH29B-V, high frequency pentode, second picture is datasheet, first line is heater voltage when cathodes are in series and in parallel - 2.4 and 1.2 V, then comes heater current - 56-68 mA if cathodes are in parallel, then plate voltage - 60V, plate current 3.6-7 mA, first grid voltage - need a bigger picture, first greed back (or how it is in English?) current- 0.3 mA, second grid voltage - 45 V, second grid current - not exceed 0,5 mA. These are normal exploitation conditions, below there are list of parameters for extreme functioning mode.

[Brymus]

Thank You here are links to the full size images:
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=50871&g2_serialNumber=1
and
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=50867&g2_serialNumber=1

I would really like to know as much about them as possible.
Thank You,
Bryan

[Zapp Brannigan]

Thank You here are links to the full size images:
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=50871&g2_serialNumber=1
and
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=50867&g2_serialNumber=1

I would really like to know as much about them as possible.
Thank You,
Bryan

Ok, I see. So let's continue! Second grid voltage is 0 V. Line "Крутизна характеристики" is S, for 1zh29b it is equal to 1.7-3.3, durability is 5000 hours minimum, 90% exhaust - not less than 7500 hours, closer to exhaust S decreases.

So called 'extreme' parameters are:
1. Uplate 150 V max
2. Ug2 120 Vmax
3. Icathode 8 mA max
4. P diss pl 1.2 W max
5. P diss g2 0.35 W max
6. R g1 1Mohm max

The tube is so called 'nuvistor' and designed to be implemented in space rockets, satellites etc.

P.S.: There are also 'true' submini tubes, they are close analogues to full-size tubes, contrary to nuvistors, which are designed to work with lower voltages etc. True subminies are marked as 6xxNNБ, where 6 is heater voltage, letters after it is a tube type (N or Н in Russian is for twin triode, С is for single triode, P or П is for power pentode, ZH or Ж is for high ferquency pentode etc), then comes modification number, and finally a letter which points at a tube form-factor (in case of subminies the letter is Б or B in English - submini)

[Brymus]

AWESOME!!
Thank You ZAP that really helps,as does your info on how to decipher the tube designators.
I want to try the 6N17B-V that MR Mash used a few posts back,

I believe I bought these to use as a Push Pull output stage for a sub mini amp,(since they are pentodes)
Not sure I want to push them at "extreme" tolerances though.
Even 150 plate voltage is low,so maybe somewhere between the recomended 60V and the extreme of 150V.

Really! thank you for taking the time to translate that for me,I very much appreciate your help!

[Zapp Brannigan]

Enjoy, my friend, I am glad to help.

Actually, if you are intended to build submini version of a big amp the best choice for that is 6n17b as it can easily replace 12ax7 and 6p30b which is a some kind of hybrid between EL84 and 6V6, closer to 6V6 maybe. Nuvistors are not the best choice in my opinion. Some guys here, in Russia, where I am from, tried to build nuvistor amp, but were not completely satisfied with a result. There are some contras they say, such as final sound which differs from traditional tube sound. Anyway, if you are intersted in nuvistor based stuff, you can visit this thread of our local forum: http://forum.gtlab.net/cgi-bin/yabb2/YaBB.pl?num=1249507367
I know the thread concerns nuvistor based stompboxes, not amps, but the information is interesting. Some guys know English a bit, they can explain something if there will be questions. Or punch me, I'll try to help.

[duck_arse]

a slight diersion .....

I do recall they were from MIG fighter plane controls thats it.

before the age of the mojo wires (so it MUST be true), I heard tell, I don't know where, that when the "west" got their hands on a late model russian front-line fighter, they were astonished to find it full of valves. turns out they are radiation harder (more harden?) than semicondutors in the event of an EMP.

carry on.

[Zapp Brannigan]

a slight diersion .....

I do recall they were from MIG fighter plane controls thats it.

before the age of the mojo wires (so it MUST be true), I heard tell, I don't know where, that when the "west" got their hands on a late model russian front-line fighter, they were astonished to find it full of valves. turns out they are radiation harder (more harden?) than semicondutors in the event of an EMP.

carry on.

That is almost correct, it was 1976 when our fighter-pilot highjacked MiG-25, the newest soviet fighter jet of that time. I am not shure about astinishment of 'west' specialists when they saw tubes inside that plane, but the truth is that most important electronic parts of plane, including radar, were tube based. I think it was a measure of need, because  of lack of good semiconductors. The tubes, like Brymus has (I mean 1zh29b), were designed to fill this lack (Am I saying right? Not shure it is grammatically correct). And it is also true that tubes are more durable under EMP.

[duck_arse]

the saying is fine, the spelling a little wonky, nothing we can't manage.

I've since been thinking about my source of this story, it was a fellow I knew when 18-ish. he told me a lot of stuff; 75% was his imagination and the other 40% was just wrong. it's affected my thinking ever since.

[Zapp Brannigan]

Well, your fellow wasn't mistaking much, the story is at least 90% reliable, except 'astonisment' I think. MiG-25 was a perfect machine, a true masterpiece of that time, I don't wonder if it impressed western military experts with its technical solutions and stuff.

[Magnus]

Hello @all,
I am going to order my parts but I have two questions:

IRF740 - there are some differrent types of the IRF740 available, for what specs should I look after?

Can the 18N50-Mosfet be used (less heat should be very interesting ) - again, what specs?

Would be nice to know a bit about them before odering something worse  


Greetings from Germany
Magnus

[mrsmash23]

Hello Magnus,

IRF740 - I ordered those from 2 sources, both work fine, Im posting links to their datasheets in case you use different store (hope those links aren't considered as banned advertising):

http://www.taydaelectronics.com/datasheets/A-086.pdf
http://www.futurlec.com/Transistors/IRF740.shtml

[Magnus]

Hello,
thank you - thats usefull 


Greetings
Magnus

[Perrow]

Hi Magnus

I think the 18N50 was the one I used and it worked perfectly, lot less heat. Watch out for the pinout, I think it's different. There are other versions of IRF mosfets that have better specs (lower rds on). I think the 740 was selected just because it was cheaper than other models.

Good luck building this.

[Magnus]

Thank you, Perrow

I will buy both, the IRF740 and the 18N50 and make a test because I am curious  


Greetings
Magnus

[thomasha]

Hello,

while I'm waiting for the SMPS IC for my firefly build I would like to show some pictures of the building process, hope you like it!

the circuit is the firefly with tone and master volume using russian submini tubes and the max1771 smps. Inspired by Perrow I tried a 1590a build. I'm still in the testing stage, until now everything fits in the box. I'm going to put a 2mm plastic sheet between the the enclosure and the copper layer to avoid accidents.







Cheers
Thomas