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DIY Stompboxes => Building your own stompbox => Topic started by: jjs on October 08, 2007, 09:04:43 AM

Title: [Tube] My new webpage about subminiature tube amps
Post by: jjs on October 08, 2007, 09:04:43 AM
Hi,

I just put online my webpage. It contains some information about two subminiature tube based guitar amps. While I'm not sure if it's ok to post it here I thought they may fall in the same category as LM386 based amps because of their size.

Here are the two amps in question, on the linked page are schematics and building notes. They are not really fleshed out ready to build projects, but may guide the interested in the right direction.

www.jjs.at/electronic/index.html (http://www.jjs.at/electronic/index.html)

(http://www.jjs.at/electronic/class_a_subminiature_1.png)

(http://www.jjs.at/electronic/class_ab_subminiature_1.png)

I wanted to share this with this forum because it was a very valuable source of information when I started to build guitar related effects.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: geertjacobs on October 08, 2007, 09:12:21 AM
 :icon_eek:

Beautiful!
If they sound as amazing as they look...
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: zeta55 on October 08, 2007, 09:18:29 AM
That's some awsome builds. Congratulates :D

Nice site also.

/Krister
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: brett on October 08, 2007, 09:24:07 AM
Man, they are gorgeous!

And very well layed out, and generous sharing of the technical info.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: bancika on October 08, 2007, 09:52:03 AM
Man, it looks great! Congratulations
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: drj on October 08, 2007, 12:02:06 PM
They look awesome, very nicely laid out too - great job !
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: John Lyons on October 08, 2007, 03:27:10 PM
Those look very nice. If you get a chance I'd love to hear a sound clips or two.
I'm curious to hear what they sound like.
Thanks for posting!!

John


Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: The Tone God on October 08, 2007, 03:40:19 PM
I like! :)

Andrew
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: jakenold on October 08, 2007, 04:14:26 PM
Awesome! Please do continue making those little babies!

A step by step guide would be very cool, as well as some more concrete information regarding the tubes - data, where they can be purchased, etc.

I HAVE checked out the datasheets, but for people lacking the knowledge to interpret such, it would be cool if you'd keep doing that "tutorial"-kind of articles about your creations.

Kind regards, Jake
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: Hanglow on October 08, 2007, 04:36:56 PM
 :o

Nice. Very Nice.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: MetalGuy on October 08, 2007, 04:51:46 PM
Cobgratulations! Very good job! I like the web site as well.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: slacker on October 08, 2007, 05:13:12 PM
Very nice  :)
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: jjs on October 08, 2007, 05:14:49 PM
Thank you very much for the kind words! I'm glad you like it!  :icon_biggrin:

As for soundclips: I don't know when I will be able to record some. There are two problems, first my playing skills are very, well "basic". Second, the amps are pretty loud despite their size. This is especially true for the class AB one.  I must find a time when I don't disturb my neighbours too much with my cacophony.

I know that in the end all that matters is the sound quality, so I will do my best. It may take a while though.

Actually I considered making complete build guides, maybe next time. I will think about including some information about the tubes on my page.

Acquiring subminiature tubes can be a tough task. I had already got those Phillips JAN 6021 tubes for the class A amp for 2.5 years. Back then I bought them (not cheap) from the USA over Ebay. Recently I got lucky to find two of the 5902 tubes on Ebay Germany. There was also a very good deal on www.military-tubes.com where you could by 250 g of unsorted submini-tubes for under 5 €. From that I got a lot of 5702, 5636, 6021, 6111 and 6112 mostly Sylvania, Raytheon and Telefunken. Unfortunately they seem to have run out of stock quickly and don't offer this anymore.
A good address is probably http://www.askjanfirst.de/eindex.htm (http://www.askjanfirst.de/eindex.htm). I never delt with them but they have a huge list of every tube imaginable (the page is a bit hard to navigate, try the sitemap).

Btw, I just checked my page statistics and according to them the by far most viewed images are the gut shots. Not that I expected anything else, normally I'm mostly interested in them, too.  :icon_wink:
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: Papa_lazerous on October 08, 2007, 07:18:12 PM
I like it!  very nano like, I am working on something similar myself although am taking a slightly different approach to the power supply.  Plenty of good ideas there though thanks
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: zachary vex on October 08, 2007, 07:20:20 PM
As far as making a general knock-off of my nano head amplifier, someone already beat you to it a couple of years ago.

(http://img.photobucket.com/albums/v295/zacharyvex/IMAG0160.jpg)

I like the clean look of your amps, and admire your use of the toroidal transformers as external "feet" for your second design, and especially the novel use of a toroidal AC transformer as an audio transformer.

Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: The Tone God on October 08, 2007, 10:46:14 PM
The initial comment made by Zachary Vex is intended as a joke.

This thread should be for comments and technical enquiries on the topic. Lets not turn this into a "who did what first" argument which would take away from jjs achievements and the topic itself.

Thank you.

Andrew
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: soulsonic on October 08, 2007, 10:59:08 PM
I like the Boost Converter used in the power supply. I think I'll try experimenting with one of those.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: grolschie on October 08, 2007, 11:06:34 PM
JJS, what beautifully laid out projects!  Thanks for sharing!  They're the best looking subminiature-amps I've ever seen!  :)
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: aron on October 08, 2007, 11:21:07 PM
Thanks for sharing. Very, very nice looking work!
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: km-r on October 09, 2007, 02:15:51 AM
very amazing!! cool!
cant wait for the soundclips!

 :icon_biggrin: :icon_biggrin:
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: el84 on October 09, 2007, 03:06:21 AM
JJS !!!!!!!!!  ;)
Class AB Subminiature Tube Guitar Amp --  GREAT AMp !!!!

I hope you will do same demo-sound ... I'm really interested  :P

Bye
Antonello
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: km-r on October 09, 2007, 03:08:50 AM
id rather have this thread in the members only section...  ;D
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: Auke Haarsma on October 09, 2007, 03:44:15 AM
awesome!

And yeah...clips please if you can find the time!
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: MartyMart on October 09, 2007, 04:07:38 AM
Beautiful work on that from start to finish, well done indeed :D
I Also look forward to sound clips .....
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: trevize on October 09, 2007, 04:24:16 AM
the toroidal OT idea is brilliant! :icon_eek: can't wait to hear samples of the pushpull amp!
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: T_u_b_e on October 09, 2007, 06:54:49 AM
As far as making a general knock-off of my nano head amplifier, someone already beat you to it a couple of years ago.



Me too  :icon_redface: :icon_wink:
Note how much more compact it is compared to the nano with itīs caps sticking up on top  :icon_wink:

(http://img.photobucket.com/albums/v308/Obi_one/mini1.jpg)

Regarding the power supply, which is close to what I also use....If not a complete coincidence I think that some credit to where the original design was found would perhaps be  appropriate :icon_wink:
It is a nice supply but it has a lack of safety measures in the current state IMHO.

Very nice builds though  ;D and fantasticly nice web pages.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: jjs on October 09, 2007, 10:02:05 AM
There seemed to be quite some trouble while I was not online, but it's probably better not to touch that.

Quote from: T_u_b_e
Regarding the power supply, which is close to what I also use....If not a complete coincidence I think that some credit to where the original design was found would perhaps be  appropriate :icon_wink:
It is a nice supply but it has a lack of safety measures in the current state IMHO.
This is the first time I see your amp. So if it uses the same 555 oscillator and is tamed by zeners this is coincidence, indeed.
I must admit that the supply is not particularly safe in case the zeners fail and the amp does not draw current (most probably because a tube failed / is missing). Then the output voltage rises and may endanger the filter capacitors.  I said so on my page.
Another problem would be the oscillator failing. Imho this is the worst case scenario because it would constantly turn on the MOSFET, which means that the supply voltage is shorted to ground through the transistor and the inductor. Both will get very hot till the MOSFET dies of excessive heat.
The latter could be handled by addition of a fuse, the first only by pulse width modulation in the oscillator.

I think these issues can be handled if some care is taken. I know that I wouldn't let anyone without technical experience borrow this amp, something could go wrong and till he notices it is too late. But if you know what to look for, it should be fine.

Anyway I think this amp is in fact inferior to my second one in almost every ascpect, including sound and safety.

T_u_b_e: I like the shiny transformer. Did you polish it or is it actually chromed? I have tried polishing a transformer once but couldn't get a mirror finish. Couldn't totally stop it from rusting, too.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: vanessa on October 09, 2007, 12:28:16 PM
Great work JJS! Very professional I do say!

There's a wealth of information about subminiature tube amps (on the web and in books). This type of engineering has been around for years and was at its peak in the late 50's for use in portable and car audio applications.

You can take that old portable (tube) radio that's collecting dust in Gandpa's shed and with a few tweaks make a very nice little practice amp out of it.

 8)
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: T_u_b_e on October 09, 2007, 02:13:03 PM
There seemed to be quite some trouble while I was not online, but it's probably better not to touch that.

Quote from: T_u_b_e
Regarding the power supply, which is close to what I also use....If not a complete coincidence I think that some credit to where the original design was found would perhaps be  appropriate :icon_wink:
It is a nice supply but it has a lack of safety measures in the current state IMHO.
This is the first time I see your amp. So if it uses the same 555 oscillator and is tamed by zeners this is coincidence, indeed.
I must admit that the supply is not particularly safe in case the zeners fail and the amp does not draw current (most probably because a tube failed / is missing). Then the output voltage rises and may endanger the filter capacitors.  I said so on my page.
Another problem would be the oscillator failing. Imho this is the worst case scenario because it would constantly turn on the MOSFET, which means that the supply voltage is shorted to ground through the transistor and the inductor. Both will get very hot till the MOSFET dies of excessive heat.
The latter could be handled by addition of a fuse, the first only by pulse width modulation in the oscillator.

I think these issues can be handled if some care is taken. I know that I wouldn't let anyone without technical experience borrow this amp, something could go wrong and till he notices it is too late. But if you know what to look for, it should be fine.

Anyway I think this amp is in fact inferior to my second one in almost every ascpect, including sound and safety.

T_u_b_e: I like the shiny transformer. Did you polish it or is it actually chromed? I have tried polishing a transformer once but couldn't get a mirror finish. Couldn't totally stop it from rusting, too.

You have certainly not got the design from me or my amp so no problem there  :). I got the original idea or inspiration myself from a nixie power supply design that was available on the internet years ago. I thought that yours was so much alike it that you probably got the ideas from the same source but it is a pretty simple solution so anyone may come up with something similar I assume. There is a company selling a kit:
http://www.ledsales.com.au/kits/nixie_supply.pdf
It is not tamed by zeners hovewer but I think that monitoring the output voltage (voltage divider and trimpot) in turn controling a transistor switching the oscillator on and of is somewhat more clever design. That way you almost have a built in power scaling  and can trim the output voltage to what you like.
At least heat monitoring and/or thermal shut down should be a minimum for safety though.

Btw, I have just polished my transfomer. And yeah it will rust a lot if you not put some clear coat for protection on there  :D

Best regards  :)
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: jjs on October 09, 2007, 02:49:39 PM
Thank you for posting that link, if I had known about this I had definetly experimented with it. I will try it out (maybe at the weekend) and if it works good, I may change my page accordingly and give credit where its due. Every piece that makes this amp safer / easier to build / generally better is most welcome.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: T_u_b_e on October 09, 2007, 03:37:03 PM
Thank you for posting that link, if I had known about this I had definetly experimented with it. I will try it out (maybe at the weekend) and if it works good, I may change my page accordingly and give credit where its due. Every piece that makes this amp safer / easier to build / generally better is most welcome.

You may have to adjust some components to handle enough current and improve filtering etc.

A very simple solution to some thermal control without adding or changing the circuit could be adding a small bi-metal switch which create open circuit of the the incoming 12V (12.6) at the (not  ;) ) desired high temperature. They are available from 5-200 degree celcius.

Something like http://www.elfa.se/pdf/69/06937981.pdf

They are a bit big but perhaps small enough to be able to stuff one in there. It would probably also be possible to  put a resistor and a LED over the switch and have it lit as soon as the switch is open  :). red alert  ;D

Best regards


btw A thermal fan control is pretty simple to do also. No need for extra noise  ;)
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: zachary vex on October 09, 2007, 04:35:10 PM
I use a chemical fuse, which works pretty darned well, and lights an LED if it becomes open.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: MetalGuy on October 09, 2007, 05:27:44 PM
Just to note that my experience with MC34063 is it produces whistling which goes into the audio unless you make it go out of regulation.
It looks like the problem with most of these powers supplies is they can't produce higher current /like say 30mA/ without complications.


Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: britelite on October 09, 2007, 05:34:21 PM
Very nice work. The amp's are wonderful projects but I am most impressed by the format you use describing the projects. The informational content and presentaion is excellent. Thank you.

Peace
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: jjs on October 10, 2007, 06:21:54 PM
I added some quick audio samples of the class AB amp to its project page, featuring me randomly hitting notes.

No samples of the other amp yet as I have it disassembled at the moment and am trying out the regulation from the Nixie pdf.
I will also experiment with selfresetting and temperature fuses.
Thank you for the suggestions!

I'm not sure about variable fan speed. I think that because of the steady current demand there is no room for less ventilation than there is now with the fixed fan speed. Only benefit could be at startup and also only for less than 5 minutes or so till the final temperature has been reached, I think.
Btw, it's interesting that the air flowing through the case makes more noise than the fan motor itself.
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: John Lyons on October 10, 2007, 08:33:10 PM
Those clips sound nice. It has a nice chimey sound to it.
I'd imagine that with humbuckers there is not much clean headroom as the single coil samples are a bit gritty.

Thanks for posting those.

John

Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: T_u_b_e on October 11, 2007, 03:07:54 PM
I added some quick audio samples of the class AB amp to its project page, featuring me randomly hitting notes.

No samples of the other amp yet as I have it disassembled at the moment and am trying out the regulation from the Nixie pdf.
I will also experiment with selfresetting and temperature fuses.
Thank you for the suggestions!

I'm not sure about variable fan speed. I think that because of the steady current demand there is no room for less ventilation than there is now with the fixed fan speed. Only benefit could be at startup and also only for less than 5 minutes or so till the final temperature has been reached, I think.
Btw, it's interesting that the air flowing through the case makes more noise than the fan motor itself.

These fans comes in many flavors (speed etc). If the flow with the current fan is allready just about right there is not much you can do.
You can experiment and analyze how efficient your supply is. How much power is going in and how much is used by the amp. The rest is generating heat and there may be room for improvements.
I think that you will find that the switching on/off of the oscillator method (if sucessfull with your supply) will generate less heat than now.
The air must have enough room to escape on both "suck and blow"   :icon_mrgreen: :icon_redface: side.
If there is a to small air flow area the noise will tend to  increase. I think that the noise level generally will be lower if the fan is sucking hot air from inside the case (blowing out) but this way may not necessarily be the most effecient way to use it.

Best regards / Bo

sorry for bad english and spelling errors..written in a hurry  ;D
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: MetalGuy on October 22, 2007, 09:02:38 AM
To avoid the problems with switching supplies I started running my tube pedals on an external wallwart PSU based on a 250V/10mA, 12,5V/300mA custom made power transformers. This way you have a lot of free space left.  I'm using a PC grade 3 prong /0.75sq.mm each/ cable /H05VV-F, VDE0281 certified/ but I don't know whether this complies to any safety standards for mass production. Maybe Zvex should be more competent on this subject?
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: frankclarke on October 22, 2007, 04:02:43 PM
I love the webpage design as much as the amp. Great photos too. You have a knack for design!
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: cox on February 04, 2009, 04:32:50 PM
i'm looking a quite lot for the class A amp, and now that i understand better the switchmode power supply, i think i'm gonna build it!!

so, does anybody built this sucessfuly? there are any mods that i can apply to this? i like stuff with a lot of switches and knobs :icon_biggrin:

thanks in advance
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: frequencycentral on February 04, 2009, 05:47:47 PM
Yeah, respect to JJS, his amps look amazing, and very informative and inspiring too.  :icon_cool:
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: cox on February 05, 2009, 04:42:16 PM
come on!
no one?

Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: Taylor on February 05, 2009, 05:38:14 PM
I am interested in building something like this, but I am a bass player. I realize, of course, that there's not much (if any) clean headroom in an amp this size, but I am curious about bass response. Anybody have any thoughts on increasing bass response? Would a bigger transformer be the main thing to consider?
Title: Re: [Tube] My new webpage about subminiature tube amps
Post by: Ice-9 on February 05, 2009, 06:36:10 PM
All i can say is WOW !! You have done a wonderful job on those 2 pedal enclosure valve amps. Great stuff