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#1
I'm looking to build my first tube amplifier. I have built amplifiers, pedals, and countless other electronic related projects before and would consider myself skillful. However, I have never worked with tubes before. I have three big questions before beginning.

Which amp should I build? I am looking for a warm, vintage combo amp. But the main thing I want is virsitility. I what chiming cleans and a screaming overdrive.

Where can I get all the parts for a good price including tubes. I already have many of the things needed resistor and cap wise i just need to get things like jacks and potentiometers. So what do you think?

Finally where can I learn more about working with tubes? Does anyone have any titles or books or online reasorces about tubes mainly tube amps for someone who is already experienced in electronics? This way modifiying and building the amp will be an easier process
Last edited by lil PopTart kid at Jul 25, 2010,
#2
i read a book Valve Amplifiers by Morgan Jones. that book helped a lot. this website http://www.pentodepress.com/ has a lot of resources for amp builders. also, this website http://www.freewebs.com/valvewizard/index.html has more resources too.

as far as parts go, which parts do you need to purchase? i get a lot of things from watts tube audio, turretboards.com and transformers from angela.com, tubes from ebay. chassis from brian with dirty dawgs amp.
Call me "Shot".

ShotRod Guitar Works

Custom Hand-wired Amplifiers and Effect Pedals.

Est. 2007


Source to everything I say about Guitars, Pedals, and Amplifiers: I make them.


UG's Best DIY PedalBoard
#3
Thanks for all the great resources I have been reading all morning and I hope to order that book sometime this week because it is in no local libraries.

As for parts I need things like potentiometers a few high voltage filter capacitors tubes and also a punch or odds and ends like a power cable and input jacks. As go a transformer I found a power transformer and three output transformers on craigslist for $49.
#4
What is the impedances on those output transformers, and what are the ratings of your power transformers? This will start to determine the tubes you'll be able to use.

If you're in the States, I use the following places to get all my parts:

www.tubesandmore.com
www.turretboards.com
www.tubedepot.com
www.mojotone.com

As for a versatile circuit, a simplified version of an Orange OR-120 may be exactly what you're looking for.
#5
Mmmm I very much dislike orange amplifiers and I do not see the appeal I believe they have horrible tone. I have been looking around and I think I'm going to do a 70's Dumble ODS it looks easy enough.

And I will find out about the transformers.

EDIT: here is the craigslist post about the transformers

Pair of new Trainwreck Stancor A-3801 style output transformers. 6.6K primary to 4,8,16 ohm secondary, 35 watt rated. They're new, never used. Charcoal hammertone finish. $49 each. 412-486-9135 until 10PM any day.

Also have new 3.4K to 4,8,16 ohm, 50 watt output. $65 for this one. And new power transformer to mate with any of these- $49. Or take all (4) pices for $150.
Last edited by lil PopTart kid at Jul 26, 2010,
#6
If you wanted to build a 70s ODS, you have to be very careful. The lead dress on that amp is very specific. You could do it, but it would be a steep learning curve for your first amp.
#7
Well I have built many amplifiers before and this would only be my first tube amp. But if your against the dumble what would you recommend? Tone is very important.
#8
Quote by lil PopTart kid
Mmmm I very much dislike orange amplifiers and I do not see the appeal I believe they have horrible tone. I have been looking around and I think I'm going to do a 70's Dumble ODS it looks easy enough.


No
#9
Tone is quite subjective. I like the sound of the OR120, so you'll have to be more specific.

Name some artists who's tone you like. We can try to find a common thread.

I will try to steer you clear of any 2 channel amps, or fancy switching on your first tube amp build. There is just so much that can go wrong, and I'd hate to see someone have a frustrating introduction to tube circuitry.
#11
Quote by end_citizen
Tone is quite subjective. I like the sound of the OR120, so you'll have to be more specific.

Name some artists who's tone you like. We can try to find a common thread.

I will try to steer you clear of any 2 channel amps, or fancy switching on your first tube amp build. There is just so much that can go wrong, and I'd hate to see someone have a frustrating introduction to tube circuitry.



I will listen to the orange OR120 all I know is that some of the orange amps I have played such as the tiny terror all the treble is cut out.

The tone I am looking for is a beautiful warm and gentel clean and a screaming overdrive.

The two songs I want this amp to reach the tone of is under the bridge or snow by the red hot chili peppers for clean tones as for overdrive I lik the solo in whole lotta love by led zeppelin
#12
The more wire you run (which includes controls, switches, etc), the more stray capacitance and EMF that can interfere with other parts of the circuit. This leads to very unpleasant oscillation in the form of squealing or silence.

It's easy to look at a schematic and go "I could build that," but it is much more difficult to get the layout right.

For your first tube amp build, I always recommend a 1 channel amp. It is just the way to start. You say have built amps before, and that's great. But you will be working with a different animal here. Not to say your past experience is irrelevant, it just doesn't all transfer 1:1.

So, if you could list some artists who's tone you desire, we can try to figure something out for you that will be rewarding for you throughout the entire process.
#13
Its quite possible for you to build a 70s ODS the first time and get it right. The problem though, is that so much can go "wrong" in the build. With it being a higher gain circuit, your going to have to be very careful about making sure that you soldering is all good, and that the way the wires are routed keeps them from interfering with each other.

Then there comes the discussion of which parts will make an ODS really "sound" like an ODS. I'm not convinced with all of the discussion. For me Output transformers and speakers are going to make up quite a lot of the tone of the amp that you have. Some people believe you have to use a very specific type of capacitor, otherwise you won't get the perfect ODS tone. When in reality, most of the Dumble amps probably had different parts between them. anyway.

So layout will be crucial. You can always do what people call a Dumble Lite, which removes some of the complexity and is said to give good tone as well.

But giving us some ideas of what you want to play will allow us to recommend other amps as well which you may be better prepared to build. Don't ever let someone tell you that you can't build something though. If your willing to put in the time, effort, and patience required to source parts, build the amp, and troubleshoot it then who are we to stop you from spending that money.

As far as tone goes, I've always been a fan of an AC30, so I consider its cleans to be nice as well as the overdrive. What you could also do, is clone a Fender Bassman and have some switchable things to allow you to change the voice from a Fender style to a Marshall style.
#14
Quote by end_citizen
The more wire you run (which includes controls, switches, etc), the more stray capacitance and EMF that can interfere with other parts of the circuit. This leads to very unpleasant oscillation in the form of squealing or silence.

It's easy to look at a schematic and go "I could build that," but it is much more difficult to get the layout right.

For your first tube amp build, I always recommend a 1 channel amp. It is just the way to start. You say have built amps before, and that's great. But you will be working with a different animal here. Not to say your past experience is irrelevant, it just doesn't all transfer 1:1.

So, if you could list some artists who's tone you desire, we can try to figure something out for you that will be rewarding for you throughout the entire process.



Ok I know what lead dressing is and all I didn't know it would be such a big problem any advice on how to minimize the noise made?

Also I posted just above your post on what bands and tones I want.
#16
A Marshall 18w may be right up your alley. If it were me, I'd take out the tremolo circuit. That's just a matter of taste, and it would minimize the complexity.

There are quite a few variations of the amp, but I think this demo (starting at 5:28 or so) will show you the tones you can get from it:

This is a reissue, so it may not sound quite like the real deal. This wouldn't be a bad first amp.
http://www.youtube.com/watch#!v=EFvhHbSRkf0&feature=related
#17
The tremolo circuit is just about my favorite part of the marshall 18w. I am worried about this amp though. I fear I wont get the power or distortion I want out of this amp. I watched the video the distortion sounds a little muddy I want something quite crisp. Unless I am mistaken

And @xgamer
It is funny you mention those to amps because besides the dumble those are my two favorite. I wanted to do the Vox AC30 but I decided 4 power tubes ads a lot more to the price especially every time i replace the tubes.
Last edited by lil PopTart kid at Jul 26, 2010,
#18
^ODS use four power tubes.

50W ODS arent the same beast.

Like I told you when you PMed me, you can't build amps if your cheap. They will cost you more than production amps.
#19
I should have never doubted you kurtlives I'm going to do the 18watt marshall. Any advice on where to get parts? Or a shopping list of everything I'll need for this build?

Also the thing I like about the dumble is the mid boost the bright switch and the rock and jazz switch. Is there anyway I could bring this to the marshall?
Last edited by lil PopTart kid at Jul 26, 2010,
#20
Sign up to 18w.com. They are a community devoted to learning and building Marshall 18W (and more) clones. They will have all the info you need and more. Sign up, read a ton, then ask a bunch of questions and get started.

Warm switch??? Do more research on Dumbles.

The Bright switch and Mid Boost switches can be implemented quite easily in an 18W.
#21
Quote by kurtlives91
Sign up to 18w.com. They are a community devoted to learning and building Marshall 18W (and more) clones. They will have all the info you need and more. Sign up, read a ton, then ask a bunch of questions and get started.

Warm switch??? Do more research on Dumbles.

The Bright switch and Mid Boost switches can be implemented quite easily in an 18W.


Whoops the mid boost is what I was talking about for a warm tone sorry. And I have signed up to the 18watt.com and I have not been able to login and just today i realized the owner of the site shut off the feature to add new members and he is only doing it manually so im just waiting for him to do that.
#22
Yeah, someone got sued over at 18watt.com over an amp kit. Some idiot got shocked and sued the kit maker. So, the owner is being quite cautious. That is my understanding of the situation, anyways.
#24
Haha I shall not for I am far wiser then that.
^my attempt at smart talk
Plus I would get a bigger settlement then he did if I would sue.

Well o well I will just wait till I can get an account any advice or things I can get started on before then?
#25
how much power do you need though? maybe you can pull a 18w preamp, and modify the power supply section and stick in a pair of EL34s in the output?


and muddy/crisp, kind of thing can be modified easily in an amplifier. it's not a huge deal. you're planning to play loud right? the distortion would probably be enough.
Call me "Shot".

ShotRod Guitar Works

Custom Hand-wired Amplifiers and Effect Pedals.

Est. 2007


Source to everything I say about Guitars, Pedals, and Amplifiers: I make them.


UG's Best DIY PedalBoard
#26
Yeah I am planning on playing loud and live I have decided the size is fine most of the time my amp will be mic'd and when its not ill deal with it. However if it is easy to add some power how would it be done?

That would be great to change muddy and crisp how could i do this?

Also could anyone post all the downloads on the 18watt forum because I have no idea how long it will be till I can get access.
#27
A note about the power thing:

More power does not always equal more volume. The best way to get more volume would be an efficient speaker.

A 100w amp with 92db speakers is just as loud as 10w amp with 102db speakers.


I have lost my password for the 18watt site, but Schematic Heaven has these two gems:

http://www.schematicheaven.com/marshallamps/marshall_18watt_schem.pdf
http://www.schematicheaven.com/marshallamps/marshall_18watt_layout.pdf

The layout isn't exactly how I'd do it, and I would use solid state rectification. Saying that, I realize our playing styles are quite different. You may prefer the sag of tube rectification.
#28
So which 1 12" speaker would you recommend?

I am also confused about output transformers I could always use one power transformer for both the pre amp and the power amp with transistor amps. So which ones will I need? and in the layout from schematic heaven it only shows 1 transformer. Yes also I would like to use tube rectification.
#29
Quote by lil PopTart kid
Yeah I am planning on playing loud and live I have decided the size is fine most of the time my amp will be mic'd and when its not ill deal with it. However if it is easy to add some power how would it be done?

That would be great to change muddy and crisp how could i do this?

Also could anyone post all the downloads on the 18watt forum because I have no idea how long it will be till I can get access.

to make things crisp, i would adjust the cathode bypass capacitor, or the coupling cap. bass cut is pretty much what we're doing here. i would really think about adding an option to cascade the two 12AX7 triodes though.

and as far as the rectifier goes, i think you should make it switchable between using a sag resistor, or bypassing it. or even a choke. i've read a 470R~1k resistor does the trick? i haven't made a push-pull amp yet to confirm these things. kurtlives made an amp that switches between solid state and tube rect though. and somebody else had a sag switch that uses a sag resistor, switch to bypass it. you might like it.
Call me "Shot".

ShotRod Guitar Works

Custom Hand-wired Amplifiers and Effect Pedals.

Est. 2007


Source to everything I say about Guitars, Pedals, and Amplifiers: I make them.


UG's Best DIY PedalBoard
#30
Here are all the mods i want to do...

2 inputs high and low gain and a switch to switch between the normal channel and the tremolo one.

Then I want to use 2 dual gang potentiometers to control the volume and tone of each channel instead of 4 potentiometers.

I also want to add a switch that if flipped one way will make the sound more bright and if flipped the other way would make the sound more warm and if it where in the middle it would just be normal.

Finally I want to add a 3 band equalizer. This mod I am still considering I might not do it.
#31
For a loud speaker that is not geared towards metal, I'd say the eminence swamp thang. I'm not too good with speakers, though. I usually just build a head that I plug into an electro-voice. Those speakers are expensive, and mine isn't that loud.

If you look on the layout for that amp, you'll see a blue, brown, and red wire coming out near the left side of the board. The red wire is the center tap of the output transformer. It goes to B+, which in this case is that can capacitor. The blue and brown wires go to the anodes (plates) of the output tubes.

You'll need an output transformer with a primary impedance of about 8k ohms. It will need to be able to handle 18 watts.

You'll also a power transformer that has a 6.3v secondary and a 250v to 310v secondary.

The 6.3v supply should be rated at no less than 3.5 amps. I'd say 4.5, just to be safe.

The high voltage (B+ or HT) should be rated at no less than 125ma.

If you enter "P-T270HX" on www.tubesandmore.com, that's the power transformer I'd get.
#34
Good good and my last question is about the sockets which sockets and tube covers will I need for the tubes required in this amp?

The tubes are

3 12AX7
2 EL84
1 EZ81
#35
As a side note, for transformers I would go with Edcor. In my experience with them they are better than Hammond, and they are cheaper. Its about 50 dollars cheaper to get Edcor transformers than Hammond transformers.

For Edcor
Power - XPWR007
Output - CXPP25-MS-8K

As far as tube sockets

12ax7 - 9 pins so noval
EL84 - 9 pins as well noval
EZ81 - 9 pins, so i'm sure you can guess what you need here.

I'd go with ceramic sockets as they look better, and they do feel like they are more durable to me.

For the 12ax7's get the tube shields. For the EL84 get retainer clips, and as for the EZ81 I don't know.
#36
Where do you get those Edcor transformers? I've been looking for another brand other than hammond. The only other thing I've used is Heyboer.


EDIT: Nevermind, I googled them, and found it.
Last edited by end_citizen at Jul 26, 2010,
#40
Ya, depends how nice you want to make it. Ultimately I would aim towards the higher end of the scale personally.

Don't forget about cab and speaker, that can be very expensive on it's own.

^sent you an email.
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