Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Tubes and Hybrids => Topic started by: syndromet on December 03, 2008, 03:13:06 AM

Title: First tube amp.
Post by: syndromet on December 03, 2008, 03:13:06 AM
Not exactly a hybrid, but I like to show off.  ;) Here is my first venture into high-voltage tube stuff. High Octane from AX84.
(http://i36.photobucket.com/albums/e48/syndromet/front-1.jpg)
Pretty happy with the externals. Got to find some miniature chickenheads, though.

(http://i36.photobucket.com/albums/e48/syndromet/inni.jpg)
Messy, as always.....
Title: Re: First tube amp.
Post by: joecool85 on December 03, 2008, 06:57:01 PM
Messy?  I think not.  Looks great!  How's it sound?
Title: Re: First tube amp.
Post by: Jack1962 on December 03, 2008, 09:26:42 PM
it's a lot cleaner than most Fender amps bro.
how does it's sound?
Title: Re: First tube amp.
Post by: syndromet on December 04, 2008, 03:04:19 AM
It sounds pretty good, especial the cleans and light breakup are good. I find the distortion to be a little to bright, but I guess that can be fixed with a little tweaking. To be honest, I was expecting this to beat my sansamp/Lm1875 combination, but I don't think it does. Comes pretty close, though.
Title: Re: First tube amp.
Post by: joecool85 on December 05, 2008, 06:11:15 PM
Quote from: syndromet on December 04, 2008, 03:04:19 AM
It sounds pretty good, especial the cleans and light breakup are good. I find the distortion to be a little to bright, but I guess that can be fixed with a little tweaking. To be honest, I was expecting this to beat my sansamp/Lm1875 combination, but I don't think it does. Comes pretty close, though.

SS for the win!
Title: Re: First tube amp.
Post by: sergscar on August 04, 2009, 11:09:55 PM
Hi Syndromet,
Nice job !
I'm almost starting myself to build a P1 HO or even a P1 Single Ended Lead (SEL) from AX84.
What tube has you chosen for the HO ? 02 x 12AX7 + 01 x EL34 ?

My idea is to use KT88, but I'm not pretty sure at this stage. Still canvassing the parts, since its very difficult to find some of them here (chassis is a real nightmare to be gotten...).

I'll place some pics after i build it.

Last comment: very clean set up. Congratulations my friend !

Sergio
Title: Re: First tube amp.
Post by: J M Fahey on August 05, 2009, 06:10:22 AM
"To be honest, I was expecting this to beat my sansamp/Lm1875 combination, but I don't think it does. Comes pretty close, though." ;)
Way to go, Syndromet !! What will tube snobs say now?  :tu:
Hi Sergscar. ¿Why a KT88? Use the original EL84 which sounds best, those AX84 have been designed and most important, tweaked to death by thousands, around that excellent sounding tube.  .
Chassis are a PITA for homebuilders, as any other "mechanical" component, that´s why I had to build, over the years, a "mechanical/metallurgic" workshop with lots of heavy machines to build my own chassis, speakers, and transformers.
Many Electronic Engineers/Musicians buy my amplifiers, and when asked why don't they build their own, considering they are fully qualified to do so, they answer : "It will cost me *much* more to build just one, than asking you to do so"
Title: Re: First tube amp.
Post by: sergscar on August 05, 2009, 03:07:49 PM
Hi J M,
Thanks your wise advice. I'll, then, use 01 x EL84. Frankly speaking, I used the "wrong" rule that says... the more expensive should be better... but seems to be this is not the case.

About the Chassis, please don't laught (well, you can, but not so louder, please...  :duh ) but i'm going to try a very unusual material for my first try. Here it goes my crazy idea:

Imagine a regular 12" x 16" x 2" (H) alluminium's roasting tray (those you use to cook delicious turkeys...),
turn it upside down..., and proceed marking and drilling as per your project.
The one I'm going to use have some small "flaps", which I can cut out and file without much effort.

(http://www.megaplacas.com.br/images/formas.png)

I guess the alluminium thickness is strong enough for supporting the transformer's weight, so I though... why not to give this mat a chance ?

Do you think it may work ? I'll chase the right measurement tray and post a picture.
Obviously, after I start to do the job, will post a "how to" for our forum's friends !

Sergio

P.S.: My wife is a little worried by seeing me so interested in "her" kitchen's mats... She knows me very well !
Title: Re: First tube amp.
Post by: phatt on August 06, 2009, 08:54:22 AM
Quote from: sergscar on August 05, 2009, 03:07:49 PM
Hi J M,
Thanks your wise advice. I'll, then, use 01 x EL84. Frankly speaking, I used the "wrong" rule that says... the more expensive should be better... but seems to be this is not the case.

About the Chassis, please don't laught (well, you can, but not so louder, please...  :duh ) but i'm going to try a very unusual material for my first try. Here it goes my crazy idea:

Imagine a regular 12" x 16" x 2" (H) alluminium's roasting tray (those you use to cook delicious turkeys...),
turn it upside down..., and proceed marking and drilling as per your project.
The one I'm going to use have some small "flaps", which I can cut out and file without much effort.

(http://www.megaplacas.com.br/images/formas.png)

I guess the alluminium thickness is strong enough for supporting the transformer's weight, so I though... why not to give this mat a chance ?

Do you think it may work ? I'll chase the right measurement tray and post a picture.
Obviously, after I start to do the job, will post a "how to" for our forum's friends !

Sergio

P.S.: My wife is a little worried by seeing me so interested in "her" kitchen's mats... She knows me very well !

Have you been looking at the AVA 100 project where a chap built a whole tube amp on a baking dish? ;)
Yes it has merit but not the kind of amplifier you can take to a big gig.
The pan needs to be screwed down to a solid base.

Re Cost of Single ended tube amps;
It might seem at first to be cheaper/easier to make SE....
BUT! remember PP (Push Pull)  OT's (Output Transformers) are easier to source.
with PP you can use a line transformer for a small 10 watt amp very cheap.
Phil.
Title: Re: First tube amp.
Post by: sergscar on August 06, 2009, 05:01:17 PM
Hi Phatt, so long !
I swear, never saw that project in my life.
The idea just came up during a free talk with my father in law, who was wondering why I was so worried  :grr to find some mats for building the amp... then he asked what I was exactly looking for, and firstly he mentioned abt something similar to a shoe's box... then he appeared with the roasting tray, asking if that may match, MOL, my search, and I shouted "Eureka!"
By living in South America, you can naturally develope a new "sense", for chasing mats from garbage...  :'(
The credits, in my case, goes to him (he's so grateful for having taken his daughter with me, that feels obligued to cooperate... ;D )

Anyway, your AVA 100 Project (pls send me the link) proves that I was not the only insane person around the world (I'll propose to create a community... "Insanes around the globe")

About measures, I have found a tray with the exact measures of the AX84 Project, and the lateral "flaps" would permit me to fix it onto a solid base, for sure.
The tray costed me abt USD 12,00. Pretty cheap !

I'm just deciding abt the transformers for adjusting the drilling plan. I've found a company, about 1000kms away from my town (Santos, Brazil) that can supply them by following Hammond's specifications in full, and will purchase them (both, the OT and PT, for a AX84 SEL, will cost me the equivalent to USD 120,00). Will document everything in pictures, posting them later on.

In other hand, I didn't forgot about your tone stack... just hadn't time enought to finishing it yet !
Thanks Phatt !
Title: Re: First tube amp.
Post by: phatt on August 07, 2009, 10:31:58 AM
Hello sergscar,

Well your Father in law must have a cosmic connection because the AVA100 is indeed using a cake tin,,, we call them *Lamington trays* in Australia. :loco

http://ozvalveamps.elands.com/ava100/ava101lamington.htm (http://ozvalveamps.elands.com/ava100/ava101lamington.htm)

Note this Tube Amp is built using cheap transformers,, as you don't need special OT's ,, this thing comes in at a very low cost.
I think the most expensive part is the OT , under $20 Aust.
If you want to see the *OT Trick* find the artical on *Using Line Transformers as Output Transformers*

BTW,, AVA or ANZ site is dedicated to Aussie and New Zealand Valve Amps that have been built over the years. just about every Amp built and sold is on this site.
Pages of useful *how to DIY it all.*

A couple of my circuit ideas are also on these pages,,, have a look under *Reverbs* and you will find comments on my *Maxiverb* stand alone reverb unit
Enjoy,,, Phil.
Title: Re: First tube amp.
Post by: sergscar on October 06, 2009, 08:58:22 PM
Hi friends, so long !
I was very busy and, also, my office moved back to it's original place (around 80 kms away from my house), therefore, I'm spending abt 4 hours/day caught in traffic jams... a real nightmare !

I've to say, my "baking-Pan-AX84-P1" has been finished already, and I'm very happy with it.

Last sunday I had the honour (and pleasure) to receive JM Fahey at home for enjoying a very juicy barbecue and, after tasting a nice bottle of wine... he helped me to finish the "little beast", since I was very worried abt the PT's high voltage. As you may imagine, to connect the PT was a piece of Cake for JM Fahey...
I'm very grateful for his kind help and technical tips.

Next week-end I'll have time to take some pics of the building process, for posting them here.
In other hand, the only lacking part is to build a decent case for it.

Just post a single pic for you to see the face-plate.


Keep in touch.
Title: Re: First tube amp.
Post by: Brymus on October 07, 2009, 12:16:15 AM
GREAT
I look forward to the updates.
Very nice looking from the front,lucky you having JM come over and help. :tu:
Title: Re: First tube amp.
Post by: sergscar on October 12, 2009, 01:30:44 PM
Quote from: Brymus on October 07, 2009, 12:16:15 AM
GREAT
I look forward to the updates.
Very nice looking from the front,lucky you having JM come over and help. :tu:

Hi Brymus !

As required by you, i've posted more pics of the process, with some updates of the case construction and board drilling/popullating.

Pls see the following lin: http://www.ssguitar.com/index.php?topic=1311.0

Regards,
Sergio