single ended gu50 schematic

[willie]

hello guys...im a newbie in this forum, i have a 2 pc gu50 vacuum tube, can someone here provide me a simple schematic for this kind of tube. im from the philippines and this will be my 3rd unit that i would assembled..i have a clone decaware zen el84 vacuum tube and an 6t9 compactron vacuum tube from gizmo schematic. i dont have any experience at all in electronics just self learning thru web and some help from my friend here. pls not too much hard to read schematic, just a simple one. any help would appreciated....sorry for my english.
thanks
willie

[DeathRex]

I read your message willie, I've been trying to remember what power transformer I used. I do have the schematic though. If you don't want tone controls, you can leave off everything before the second 6SL7/6N9s. Mine is switchable between triode, pentode, and UL. If you don't want that, connect the feedback resistor for pentode or UL, or use no feedback for triode. And of course if you're using UL or triode you don't need the regulator. Mine uses a combination of fixed and cathode bias. You can do that or either.

Be careful of the voltages. If you haven't yet, it would be good to find a book in PI on electrical safety.

I went to PI back in 90 or 91. Bought a calculator, original Gameboy, and a lovely bowl of icecream in a coconut husk. Yum.

[willie]

thank you deathrex...i saw your other project gu50 push pull amp, perhaps i'll try the push pull topology i have 2 unit of SET already...it's beautiful project you have done... . the single one is it an ordinary diode are you using? and the gu50 filament is it a 6.3V sir? can i use 5u4g or 5ar4 rectifier tube, i dnt have here right now a 5C4S and can you provide the specs of choke your using. sorry sir for the inconvenience and how do you find the PI when you visit my country? is it good and did you enjoy staying here...maybe you try to taste the adobo its a good food we had here......i hope you can visit again my country...you are here way back 90's and lots of happening and changes here from then....thanks
regards deathrex......sorry for my english.
by the way from what country are you sir...
willie

[DeathRex]

the single one is it an ordinary diode are you using? and the gu50 filament is it a 6.3V sir? can i use 5u4g or 5ar4 rectifier tube, i dnt have here right now a 5C4S and can you provide the specs of choke your using.

The single diode attached to the GU-50 filament transformer is for the fixed part of the bias. GU-50 filament is 12.6 volts, the filament transformer is 12.6-0-12.6, so it can do 2 X GU-50 across the whole secondary. For PP GU-50 you'll need a 5U4 or 5AR4, but keep the bias at or below 100ma for each pair. The choke is just a 1.5H at 250ma, could be from 0.8 to 10H.

sorry sir for the inconvenience and how do you find the PI when you visit my country? is it good and did you enjoy staying here...maybe you try to taste the adobo its a good food we had here......i hope you can visit again my country...you are here way back 90's and lots of happening and changes here from then....thanks
regards deathrex......sorry for my english.
by the way from what country are you sir...
willie

PI = Philippine Islands, yes it is a very pretty country, very green. I was in the Navy when I visited Subic City. Got to see a bit of the Philippines when I rode a bus to Manila, and then see it from above in a plane when I was flying back to the US. On Guam pork pancit was big along with another dish that I forgot. I'm from Colorado USA.

[willie]

thanks sir i really appreciated your help...now i can start building my own gu50 amplifier...just a single ended i have 2 pc. gu50 tube only available here. you are enlisted to US navy before, yes subic i wont forget that place cause for once i did take an exam to be enlisted but failed in an interview....
again thanks sir. regards
willie

[willie]

good day again sir....one last favor thing sir...your trapos and opt on top of your amplifier was 4 pcs.....2 for output transformer a 3.5k 8ohms 75ma, choke inside of the mainframe was 1.5H at 250, the power trapos are 2 pcs.....one for gu50 and the other was the main trapos for 6sl7 and 5c4s..pls can i get the full specs of your main trapos....(gu50 and for 6sl7/5c4s) how many volts im going to use for both trapos sir....AC here was 220V primary the DC sir how many volts for the secondary...im going to use sir.....thanks again....i hope im not abusing myself for the favor i've been requested...
regards...
willie

[DeathRex]

Volts out of power supply depends on several things. Current for each GU-50 should be 90-110ma. I think the transformer I used was a 295-0-295, but if you use a 5U4 you'll need more voltage, maybe a 320-0-320 both at 230ma minimum. If you don't have it, install PSUII from duncanamps.com. Change output to constant current at 200ma.
Output transformer is a Edcor gxse15-8-3.5.

[willie]

good day again sir just an inquiry for tube gu50...how will i know the number 1 in gu50 tube sir....if im going to start counter clockwise from 1 to 8? there is no mark which is which in the socket and the tube itself....too confusing...
thank you for the help..
regards
willie

[DeathRex]

What kind of socket are you using?

[DeathRex]

So far all that I have installed have used the cage sockets with the guide for pin 1. If you don't have the cage on top of the socket, there are 2 ways to install the tube, don't install it the wrong way. Goto tubedata.org click on the Hong Kong flag for Tigahost, click 'G', find GU-50 with brand name Lamina and click on GU50.pdf and it will show you the pins.

Or start here http://tubedata.tigahost.com/tubedata/sheetsG.html

Pin 1 is inline with the bulge in the glass, then clockwise to 8.

[willie]

yeah....i see with the bulge in the glass that's the 1 and clockwise count to 8...yessss thanks thanks again sir and also it has a small dot underneath the glass. whe'www,
many thanks

[Geek]

Who else noticed the diode on the GU50 bias is backwards?

[DeathRex]

Oops.
I had to replace it, because I couldn't edit it enough in photobucket.

[jetpack]

Hi all.

Deathrex or other, any idea if the bass and treble pots in this schematic should be linear or log? Thanks!

As an aside, I'm hoping diytube lives through Shannon's relocation. I've learned tons on here through building a couple of gsg and eiclones. Thanks to all who share their knowledge.

[DeathRex]

The bass pot is log, and the treble pot is linear. It all comes from Angelfire's All About Amplifiers, Tone controls
http://www.angelfire.com/electronic/fun ... -Tone.html

Of course don't get confused with Angelfire's Practical Tone Control Circuits
http://www.angelfire.com/electronic/fun ... one-A.html

A Tone Control You Can Love is in there, but it's been surpassed by Morgan Jones Tone Control in his 4th edition. I found that I almost never turn the treble or bass down. With Angelfire's True Bass Boost and Treble Boost you can only increase the bass and treble, but you also only get a extra tube and resistor in the way of the signal when the controls are turned all the way down.