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    Building, troubleshooting and testing of these amplifiers should only be
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Help with making a tube amp?

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Hey everyone! How is it going??
I'm very new here, just registered.. I'm from brazil and i'm trying to make a tube amp for myself! :D i have a marshall mg 50dfx and it plays sweet...but i played a fender tube one... and fell in love with it...
i have already built a gt2 copy, but also own the original, and found very interesting making it.
my dad helped me a lot, he's a mechanical and electrical engineer :D
so...
i asked him about making an amp... and he liked the idea! :D
so,...any ideas on where to start? maybe some website i can find a project or something?
i have no idea at all about making it..
my dad wanted to make a transistor amp... but tube ones sound A LOT better.. heh.
so, any ideas where i can get maybe the schematics, or circuits, or anything like that?
any help will make me happy!!
i'm sorry for my bad english, also!!
thanks a lot in advance!!
 
If a "classic" fender design is what you are interested in you may wnat to check out Weber Speakers web site and go to their "Kits" page. I'm fairly sure that they ship internationally and their kits are good and fairly straight forward especially if you have your dad, with his experience, helping you out.
MikeJ
 
Ok, I've been checking the websites for some minutes, and I have some questions:
How should I choose which amp to build?
Should I just get a schematic and buy all parts, or should I buy a kit?

I don't really know the actual difference between amp types, except for the sound quality... So, I was looking at tube amp projects, and it's mainly a "head", right? Should I build a "head" or a tube amp, that's already got speakers in it? Are there differences?

By the way, sorry for all those questions, and please let me know if this is ok to be done in the forum, ok?

Thanks again!
 

G

Member
Joined 2002
victubescreamer said:
Ok, I've been checking the websites for some minutes, and I have some questions:
How should I choose which amp to build?
Should I just get a schematic and buy all parts, or should I buy a kit?

I don't really know the actual difference between amp types, except for the sound quality... So, I was looking at tube amp projects, and it's mainly a "head", right? Should I build a "head" or a tube amp, that's already got speakers in it? Are there differences?

By the way, sorry for all those questions, and please let me know if this is ok to be done in the forum, ok?

Thanks again!

What type of music are you wanting to play? As far as which to build goes I would build whichever style you consider more convenient. I like to build head units because I think they provide for better ventilation. Some like combo amps because they are more convenient to haul around.
 
You mentioned in your original post that you really liked a fender amp that you tried so.....

Last post is right on "what type of music do you like" ??? Do alittle research regarding the amps that are being employed by artists whose "tone" you enjoy and start there. [remembering that no amp or guitar are going to give you the tone that your fingers and heart can].

Do a little web research on that different tube classics; Fender, marshall, Vox, etc.

Decide what power you really need. Unless you are playing football stadiums regularly I'd recommend that you stick with a smaller amp that will please you at home as well as working for club gigs etc.

There are several good books available regarding the history and design of some of the classics.

Once you have made a decision then you can decide which is more cost effective for you kit or parts.

I think the good quatlity kits are a great way to start. Everything is there including a nicely stenciled chassis and panel all punched and drilled and ready to go. Usually a well laid out tag or eyelet board, well built cabinet, etc. You can always "upgrade" or "customize" small parts, resistors, capacitors, transformeners and so on.

My money's on a good low watt 12 to 25 watt kit like a 5e3 or AC15 or marshall 18 for a first project.... it certainly helped me get a handle on organization, technique, and REALLY understanding the circuit and finer points of design and construction.

As to head or combo personal taste and preference go along way here. Both have their strong and weak points and it really comes down to what you pick for that first build. I've done both. You can't beat a well built " 5e3 Tweed deluxe Fender" for ease of transport, great "blues" tone and great all around home and club amp. Ive built some heads as well [ AX84 ] that are great sounding and versitile by switching speaker compliment and cab types.

CAREFULL WITH ALL OF THIS SOMETIMES ONE IS ALL IT TAKES TO GET YOU HOOKED!!!

Good Luck to you and your dad

Mike J
 
champ

If you want something to get started and want immediate results without too much headache I'd suggest making a Fender champ - the earlier the model, the better.

And leave combo format for later experiments - head is easier to carry around and you can also plug it into different cabinets.

As for tube amp kits - it's a bit too simple and I don't like that. You buy a kit and assemble it without learning too much. The benefit is that it will probably work, but it'll cost too much and you will not be saying "I"ve built it myself!" in the end.

If I were you I'd go to a junk second hand shop, find and old trashed radio or patiphone with tubes and make a nice little guitar amp out of it.

good luck!
 
First of all, I wanna thank you all for your answers! :)
I'm really analyzing every possibility you guys told me about.

One thing: mikecj, I kinda agree with engels, when he says that making an amp with a kit, won't be giving me a lot of experience. And, it is one of the things I'm seeking. =D

engels: "If I were you I'd go to a junk second hand shop, find and old trashed radio or patiphone with tubes and make a nice little guitar amp out of it.", I actually don't really know about that, here in Brazil. I'm gonna ask my dad about it, when he gets home from work.
I hope I can find something like that, but, here in Brazil, technology is not as cheap as in the USA, even when it's about some old stuff. Crazy world, huh?

Another thing my dad mentioned is... We play here, a Marshall MG50DFX, and that gives us a good volume.
We checked out the site http://ax84.com/legacyprojects.html , and they have some cool projects, and my dad thinks we could build them, but... They're all like 5W, while my Marshall is 50W.
So my dad asked me to try to find a project of a tube amp with about 50W, what do you guys think?
And, another question: If I make a head, do I just go and plug it to compatible speakers or what? I have really no idea of how it works.
I mean, I've seen JCM900... Is it supposed to look like that? A head and the speakers?

Thanks a lot! :D
And I mean it, A LOT!
 
I am just about to embark on an amp for my son. Having built a couple of audio amps from scratch, I am going to use a kit for the guitar amp.

Check out the guys at http://www.mojomusicalsupply.com/ they sell just about everything you need to make a good tube guitar amp and they will sell you a kit with all of the parts including chassis and cabinet

I am looking at the fender tweed deluxe myself.

Good luck,

Rob
 
Disabled Account
Joined 2004
victubescreamer said:
And, another question: If I make a head, do I just go and plug it to compatible speakers or what? I have really no idea of how it works.
I mean, I've seen JCM900... Is it supposed to look like that? A head and the speakers?
A combo is an amp with a speaker in the same wooden box. A head or piggyback is only the amp in a wooden box. And you must connect this head (amp) with the speaker(s). So you need to build another wooden box to place the speakers in it. Or buy one.
Of course speakers must be for guitar use. Like Jensens, Celestions or whatever.

If you liked a Fender amp I recommend any Fender schematic with one pair of 6L6s. Just build the output stage with one preamp channel to make things more easy. Unless you need a reverb or vibrato or a second preamp. But as I understand this is your first project, so do it as simple as it can be!
 
50W

There's a reason why the beginners' projects are all 5W and not 50W. To put it simple, it's about 10 times more complicated to build 50W than 5W. I strongly suggest starting with 5W if you want to learn - but if you simply need a 50W than go buy one or buy a kit.

And volume-speaking, your 50W marshall is roughly comparable to a 20W tube amplifier so if you're looking for the same amount of power - look for a 20W project like Deluxe. 50 tube Watts is very loud.
 
Here is a simple Schematic of a Fender Princeton. What you could do is buy a bigger output transformer (3K primary) and power transformer and replace the 6V6 with a EL34 and get around 10 - 12 watts out. That is what I plan on going if I ever get around to building it.
 

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Again, thanks for all the answers. And let's get to it:
Thanks resident, for the explanations, in the first place.

engels: Ok, I get your point. So, yeah, I'll start with a 5W then. But, one thing, is there any specific project I could follow?
With schematics and bill of materials, if you could get me.
Another thing, as far as i knew when we talk about Power, it's about the audible output from the Amp. That's actually what my dad said in portuguese, and I tried to translate it my way into english. Is this correct? What we did not understand is how the Output power of an 20W can be as loud as the 50W non-tube Marshall.
Can you enlighten us a little bit on that matter? Thanks again! :)

Gavin: Hey! Thing is, when you say "buy a bigger output transformer (3K primary)", do you mean a 3kW? And what's the original Wattage of this Fender Princeton? Also, where could I get extra info on it, like the Bill of Materials?

Thanks again, everyone!
 

G

Member
Joined 2002
victubescreamer said:


Gavin: Hey! Thing is, when you say "buy a bigger output transformer (3K primary)", do you mean a 3kW? And what's the original Wattage of this Fender Princeton? Also, where could I get extra info on it, like the Bill of Materials?

Thanks again, everyone!

What I mean is that a EL34 needs a plate load of 3K to get the optimum performance out of the tube. A 6V6 uses a 5K primary impedance. Here is a link to the output transformer I was going to use.

http://www.allenamps.com/parts.php#transformers

Look at the TO11C transformer. With this transformer and a little higher voltage on the output stage you can have a screaming little 12 watt amplifier. If you decide to go with this simple circuit I will try to post some schematics with the revised values.
 
Disabled Account
Joined 2004
Vic,
As you'd like to learn you must buy a book with some tube theory or find some nice articles with blackle (google) search! :D
A tube amp sounds much louder cause it doesn't clip (distort) like a SS amp! The clipping is more "rounder" and sounds nice!
The Princeton is around 3-5W. Do some blackle search on it, and you'll find more! The bill of materials depends on the parts you will use. Transformers, tubes, caps, sockets, chassis, pots, e.t.c.
It's yours choice. That's why some fellows over here find old stuff and ruin them to get the parts! The most expensive parts are the transformers and the tubes. And of course the chassis and the cabinet ....unless you'll built it in a junk box!
 
junk

victubescreamer said:
I hope I can find something like that, but, here in Brazil, technology is not as cheap as in the USA, even when it's about some old stuff. Crazy world, huh?[/B]

My suggestion for locating a trashed tube device is not as complicated as it seems. Every second grandma has some tube radio or record player hidden somewhere in her storage in a non-working condition. There are second hand shops everywhere and there' s still a chance to find tube-something. Even in Israel where I live.

Now when you find it you basically have a kit: there's a power transformer, an output transformer, sometimes a speaker and sometimes the tubes are useable as well. Then you see what power (output) tube is there and according to this see what guitar amp may be made with your "kit".
You will probably need to buy some resistors and capacitors for the new circuitry then.

And if you want to make a shiny new amp from new parts you may buy a SE 5W kit and they usually allow design flexibility so you may decide whenever you want a Champ, a Princeton or whatever AX85. Although I've said you won't learn with a kit you may do it the hard way, change the design and suffer not less.

The difference is in the price. Old mono vinyl player will cost you $20 and a 5W tube amp kit - $400.
 
Somewhere on the net is a chart that compares wattages to decibles.
It says that a 5 watt amp is only 1/2 as loud as a 50 watt amp into the same given speaker and cabinet.
Having built several 5 watters and a few 10-30w PP amps, I would definatly have to say start out with a 5 watt. Its simple, they run on low voltages (as compared to a 50 watt amp, you only have 250-350v with a 5 watt and over 400v with a 50 watt!:hot: ) and their layouts allow you to learn how the components work and why certain things must go next to each other, or why your power transformer should be located away from your input tube etc etc.

I started out with help on this forum and from ax84, I highly reccomend ax84's website. Build the P1 , or if you really love vintage marshall tone it is very hard to beat their High Octane amp. If you build the high octane or the P1, there is a quicky intro to tubes and how they work and how to use them. I bit the bullet and built the HO as my first 'real' tube project and am glad I did. While it is a bit more complicated than a P1 or a champ, it sounds incredible and is IMO, far more versatile for rock. For blues I plug into my little champ clone and crank it to 10.

The nice thing about 5-ish watt tube amps is that they are about as loud as a 10-15 watt SS amp (depending on the speaker you use) and allow you to crank them up to get that good ol' tube distortion at levels that wont necissarily ruin your ears. ( or the neighbors either- just don't do it at 1 in the morning though!)

Here are some links for ya to gander at!

http://www.ax84.com/index.php/legacyprojects.html?pg=legacyprojects&project_id=hioctane
Schematic:
http://ax84.com/media/ax84_m314.pdf
Build guide/theory crash cource:
http://ax84.com/media/ax84_m322.pdf

Hope this helps!
Be careful, you might get hooked!;)
 
Check out the musical instruments forum. We've been talking about Fender Champ clones. My son and I built one and he loves it.

I *measured* 3.4 watts and it is plenty loud for the music room. Plus the little guy can carry it to a friends house.

I sourced most of the parts from an old tube radio and used a Squire SS amp for a cab.

rick
 
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