gonna build my own amp!(i think)

[tommywho5150]

im thinking about building my own valve amp, but i have no real experience of building them. ive owned tons and still do but im seriously toying with the idea of building a single channel 1 trick pony gain monster of an amp, so my question to start with is:

what am i gonna need and where can i get schematics and advice?

i know theres gonna be a ton more questions but for now i think this is the important one im probably just gonna go to radio shack for most of the parts.
also im not wanting to make it much more powerful than about 75-100 watts

much respect

tom

[batch]

First of all: I added you to my friends over Myspace.
Second: are you sure? I think it would cost less buying a second hand than building your own.
In valve (tube for you Americans ) amps there is high voltage involved, and, unless you're familiar with electricity, i wouldn't reccomend to do things on your own.

[HipCat5]

Good Luck on building your own tube amplifier. Its pretty fun. I built a 6v6 push-pull amp with a JCM 800 preamp on it and while its not perfect, I learned a lot and it is a useful amp.

Here's a few tips:
1) Head on over to http://www.ax84.com and http://www.18watt.com and become a member there and post any questions you might have. The community there is very knowledgable. The AX84 site has some nice designs you'll want to look over too. They'll probably give you a good place to start.

2) The costs associated with building a tube amp can be offset if you can find an amplifier in an old console radio or PA amplifier that can be used as the basis for your particular amp design. For example, if you want to build a JCM 800 6L6GC based clone, keep your eyes open for perhaps an old Bogen PA. In my case, I found an old Sears Silvertone console record-player which had in it a small chassis with 6v6 push-pull and 3 preamp tubes (12AX7, 12AX7, and 12AU7). That configuration was perfect for a small Fender amp. I started there but ultimately designed a larger preamp for the power section and it grew from there.

The Transformers are the thing you're going to want to buy used because they're pretty expensive new. Contact old ORGAN repair guys and ask them for any surplus or spare transformers ... you'll be amazed at the deals you'll get from them. They may even want to talk SHOP with you since not many people are interested in tube amps besides musicians.

3) The biggest lesson I learned in building an amp from scratch was that AC wires need to be twisted tightly to reject noise and that LEAD DRESS is critical to a good amp design. LEAD DRESS is the concept of laying out your wires such that a one wire doesn't interfere with another's performance. For example, on a tube socket, always solder the GRID RESISTOR to the socket with a very short lead on the socket end. This rejects noise (especially on V1 because V1 is the first tube and most noise is injected there). Likewise, never run wires in parallel to each other from a socket ... always attempt to cross wires at 90 degree angles to minimize hum & noise. There's more tips on the previously mentioned sites.

4) STAY SAFE! Most tube amp designs you're going to run into are high voltage. NEVER use two hands to check a circuit ... always clip one side with an alligator clip and use 1 hand to check with a meter or tool. If you're not comfortable with working with voltages of this nature, you might want to consider something with FETs and low voltages (same principals apply but working with lower voltages).

If you're interested in FET based designs of some very COOL circuits, I found this site to be nice:

http://www.runoffgroove.com/thunderchief.html

Good Luck. Building amps is very rewarding & I think if you're smart and a bit thrifty, you might build a nice amp for much less than the cost of a new/used one.

Later!

[tommywho5150]

First of all: I added you to my friends over Myspace.
Second: are you sure? I think it would cost less buying a second hand than building your own.
In valve (tube for you Americans ) amps there is high voltage involved, and, unless you're familiar with electricity, i wouldn't reccomend to do things on your own.

i got your add dude, im in england so i know what valves are...lol
plus the worrying thing is being in england our mains voltage here is 240 volts opposed to 110-120 elswhere.
but im pretty used to working with electrics i worked for a company designing and building wiring systems for cumins engines and i studied electrical engineering after leaving school before the army

[tommywho5150]

Good Luck on building your own tube amplifier. Its pretty fun. I built a 6v6 push-pull amp with a JCM 800 preamp on it and while its not perfect, I learned a lot and it is a useful amp.

Here's a few tips:
1) Head on over to http://www.ax84.com and http://www.18watt.com and become a member there and post any questions you might have. The community there is very knowledgable. The AX84 site has some nice designs you'll want to look over too. They'll probably give you a good place to start.

2) The costs associated with building a tube amp can be offset if you can find an amplifier in an old console radio or PA amplifier that can be used as the basis for your particular amp design. For example, if you want to build a JCM 800 6L6GC based clone, keep your eyes open for perhaps an old Bogen PA. In my case, I found an old Sears Silvertone console record-player which had in it a small chassis with 6v6 push-pull and 3 preamp tubes (12AX7, 12AX7, and 12AU7). That configuration was perfect for a small Fender amp. I started there but ultimately designed a larger preamp for the power section and it grew from there.

The Transformers are the thing you're going to want to buy used because they're pretty expensive new. Contact old ORGAN repair guys and ask them for any surplus or spare transformers ... you'll be amazed at the deals you'll get from them. They may even want to talk SHOP with you since not many people are interested in tube amps besides musicians.

3) The biggest lesson I learned in building an amp from scratch was that AC wires need to be twisted tightly to reject noise and that LEAD DRESS is critical to a good amp design. LEAD DRESS is the concept of laying out your wires such that a one wire doesn't interfere with another's performance. For example, on a tube socket, always solder the GRID RESISTOR to the socket with a very short lead on the socket end. This rejects noise (especially on V1 because V1 is the first tube and most noise is injected there). Likewise, never run wires in parallel to each other from a socket ... always attempt to cross wires at 90 degree angles to minimize hum & noise. There's more tips on the previously mentioned sites.

4) STAY SAFE! Most tube amp designs you're going to run into are high voltage. NEVER use two hands to check a circuit ... always clip one side with an alligator clip and use 1 hand to check with a meter or tool. If you're not comfortable with working with voltages of this nature, you might want to consider something with FETs and low voltages (same principals apply but working with lower voltages).

If you're interested in FET based designs of some very COOL circuits, I found this site to be nice:

http://www.runoffgroove.com/thunderchief.html

Good Luck. Building amps is very rewarding & I think if you're smart and a bit thrifty, you might build a nice amp for much less than the cost of a new/used one.

Later!

hey dude thanks for those sites and the advice, i just spoke to a guy who used to repair old radios and he's said any parts i need i can have if he's got them.
as for those sites u mentioned i have had a quick look round and they seem very interesting and i will join later today when im not working (im actually tattooing someone while im typing this, well he's gone out for a smoke so i thought i'd pop on here and check..lol)

once again thanks for the advice

tom

[guitar08man]

try looking at this company named weber, they make amp kits, which is something that i looked at for a while (never worked up the cahones to build an amp myself)

If you were going to build and amp id keep the wattage VERY low, something like 1/2 to 5 watts. 5 watts is still very very loud, the power tubes will just saturate quicker, which is good if you want that Van halen-y sound.

poke around on www.amptone.com and https://taweber.powweb.com/store/kits.htm

hope this helps!

[lil'devil]

very cool.

i always wanted to build the california dreamer projects for ax84.com but just never got around to it.

bought a $400 johnson modeling combo amp instead - enough sounds and toys to really give me a good run.

[tommywho5150]

a quick update for everyone who's interested:
i bumped into a friend who i haven't seen in a few years today, he told me that he has an old 100w p.a. amp sitting in his loft and i can have it for £10! ($20 ish) all thats wrong with it is the rectifier is f**ked but everything else is there(transformers etc) im picking it up at the weekend but as yet i have no other info about it exept it runs el34's, when its here i'll stick some pic's up and then get started.