ZH Boost - subminiature tube booster

himister · Post by **himister** » 28 Oct 2009, 22:32

Mr. G. wrote:Goo stuff bud!

Circuit and build looks awesome! Got any soundclips?

Did you have to do much alteration to the template for it to work with the Eddystone enclosure, or are they pretty much the same as the 1590a?

Thanks...much.Mr.G.

No soundclips at the moment but I was planing to make them soon, couple of days or so.
Template...

I guess I didn't have to work too much. I've just import it and edit vectors a bit. As you said in your post some resizing was needed and I marked values with metric system. Enclosure sizes doesn't vary to much...check it.
http://www.hammondmfg.com/pdf/1590A.pdf
http://www.hammondmfg.com/pdf/27969PSLA.pdf

I see now some values in the pdf are floating outside page margins...

need to fix that.

borislavgajic · Post by **borislavgajic** » 03 Nov 2009, 20:18

gena_p1 wrote:Looks very cool! Valve alternative to MXR Microamp and SHO.

And these tubes can be used in phasers

hi Russian friend.....zdravo ruski druze!
.....I am especially interested in tube phasers(and wah-vibes).......so can you send us some more ot these tubes ?

boris

...and himister this is way too insane....so smalll and perfectly inside........thanks man

himister · Post by **himister** » 03 Nov 2009, 23:23

hi Russian friend.....zdravo ruski druze!
.....I am especially interested in tube phasers(and wah-vibes).......so can you send us some more ot these tubes ?

boris

...and himister this is way too insane....so smalll and perfectly inside........thanks man

Здравствуй товарищ. Pozdrav prijatelju.

Thanks for the high praise Boris.
Right now I expect one other submini tube model from my friend to obtain for me. Something caled 1SH24B or 1P24 or something like that. Hope I'll pick them up tomorrow. I'll let you know when I got them and do some testing. For other then these two, I don't know much in what kind of circuit they would be useful. We'll find soon I hope.

Insane...

indeed...I was looking to make something that size since I don't see the need for the booster to be in a 1590BB size enclosure or something gigantic. Small, practical and tube sounding.

Cheers bro.

Tube2stomp · Post by **Tube2stomp** » 04 Feb 2010, 03:12

himister wrote:
kurtlives wrote:Why do you have the screen at a higher potential than the plate? I always thought that was a no no.

Personally Id stick with the 317. It's more durable and precise than a resistor.
To be honest...I don't know. Maybe datasheet is faulty and they swapped screen for plate.
When I tested the tube for the first time I used a resistor to keep a different potential to anode and it sounded like crap.
In one moment I connected screen directly to supply rail and it cleaned it self.

With such a LOW plate voltage there is not enough pull on the electron cloud.
When you connected the screen to the rail it could pull the electrons, because it is closer to the cloud then the plate.
This is kind of what is going on with low voltage car "space charge" tubes.
Your tube didn't go bye bye because with such a low voltage and not much current drive the screen *couldn't* kill it self.
Now that you have higher voltage, it would be wise to try and limit the screen so it won't go belly up... if it can.

And on a personal note:
Fish needs water
If you'll put a fish in a bowl with only half a glass of water
It won't be happy
You won't be happy

Tubes need high voltage
Give them high voltage
They'll glow happy
And you're guitar will sound healthy!

(sorry, I hate seeing tubes run on low voltage [smilie=wine.gif]

)

himister · Post by **himister** » 04 Feb 2010, 08:57

Tube2stomp wrote: With such a LOW plate voltage there is not enough pull on the electron cloud.
When you connected the screen to the rail it could pull the electrons, because it is closer to the cloud then the plate.
This is kind of what is going on with low voltage car "space charge" tubes.
Your tube didn't go bye bye because with such a low voltage and not much current drive the screen *couldn't* kill it self.
Now that you have higher voltage, it would be wise to try and limit the screen so it won't go belly up... if it can.

And on a personal note:
Fish needs water
If you'll put a fish in a bowl with only half a glass of water
It won't be happy
You won't be happy

Tubes need high voltage
Give them high voltage
They'll glow happy
And you're guitar will sound healthy!

(sorry, I hate seeing tubes run on low voltage )

Thanks for the comment....

Few things first....This particular tube was designed to run at max plate voltage of 60V as you can see from datasheet.
What I wanted to do is to make a clean booster that could fit nicely into A size enclosure...so if you have proposal how to stuck all that, and add supply which can produce near 60V from 9V wallwart that would be awesome...somehow I doubt that could be done even with all kind of voltage multipliers and if it is SMD made too...
Just to say I am satisfied how this thing sounds in this configuration (if we forget

that these particular types of pentodes are microphonic) this is really low cost, nice, clean booster.
I have few other ideas how to implement pentode in this kind of circuit, look here but, later about that. Also I'm not the first and surely not the last to use this kind of tube in this manner. See this.
I agree that tubes like more voltage but sometimes it's interesting to do stuff different.
Anyway, thanks for your opinion.
Cheers

Tube2stomp · Post by **Tube2stomp** » 04 Feb 2010, 22:07

I love subminis, built several amps from them but not a pedal yet.
And yea a tube pedal in that tiny enclosure of yours is just too damn cute

Since you already have a wall wart, why not make it DC?
This will clear space in the enclosure, keep AC and switching noise away from parts in this clastrophobic pedal build, keep AC away from others pedals on your board...
Hmmm I see only positive points here

himister · Post by **himister** » 04 Feb 2010, 22:39

Thanks mate!

I don't know if you have looked closely at schematic posted.
Supply is made from voltage doubler and full wave rectifier inside enclosure. Testing wallwart was rated at 9VDC 300mA and filtering was important to clean the hum from it. To say it works very well just on 9VDC filtered but Rick (FC) was kind enough to point out that with doubled 18V tube will have more headroom so I did it that way too and crammed into enclosure.
As I said going any further will make BOM bigger and there's no space inside also I'm not fond of tinkering with SMD just to make it more compact..I don't see it's worth of trouble.
Soon I hope I will post a new one with different tube and configuration...need some testing on the bench.
Also I'm considering using one of the SMPS designs to beef the voltage and current and that one will be in at least B size enclosure....

Tube2stomp · Post by **Tube2stomp** » 05 Feb 2010, 02:04

I looked again and now I'm more confused

First of all I thought you had *AC* going into the pedal, doing rectification and regulating all inside.
Then you say it was a 9V*DC*... but it's a 9V*AC* now... and you put a doubler (which IS a rectifier) going INTO a bridge rectifier?

I'm lost mate

But I still love the enclosure

himister · Post by **himister** » 05 Feb 2010, 02:55

Sorry... I forgot that I was doing first tests with 9VAC 1000mA walwart, and after some time I used other one which was the 9VDC 300mA, Roland made, I use it for testing all 9V pedals. I apologize for confusion mate

guess I lost it too.

Anyway it works with both...Glad you like little box.

Tube2stomp · Post by **Tube2stomp** » 05 Feb 2010, 14:06

As long as we have fun, who cares about the rest

Can you just explain why you put a bridge rectifier after a doubler?
The doubler's output is DC... not AC

himister · Post by **himister** » 05 Feb 2010, 16:24

Right! Fun it is!

Doubler was there to increase the voltage..naturally, and I also put rectifier for the purpose of extra filtering, since at first test I used AC source and I had some previous good experiences with extra filtering in pedals...you just never know what kind of wallwart will be used and to be on the safe side. I have this practice whenever I can, it's low cost component and doesn't hurt to be there.

Also the circular rectifier I used nicely fits under the filter cap and since I didn't use PCB for this one, I just solder it directly and made wire connections under...job done!