Noob looking to build a tube amp

[shugs81]

Hi Guys,

I'm interested in building a 100/200w Tube amp... or possibly head and cab... minimum 2x12 mainly cause i got a knackered carlsbro glx150 with 2 celestion(??) speakers sat doing nothing!!

I'm looking to build a smaller practice amp first before I go for the main one (for the practice!!) and was also wondering if there's a decent 1-5w kit anywhere that isn't £600?

I mainly play heavy rock at the moment but I also like playing punk/ska stuff too and was hoping for something marshall-y in sound.
Not looking for any extra effects and I want 2 channels... possibly both exactly the same tones & gian stage so I can use different guitars and level them out through the channels rather than messing with volume pedals! one guitar is quieter than the other and the loud one's volume is pretty much on or off!!

would also be looking to have a footswitch too to switch channels...
and maybe a switch so that if i was only using one guitar i could make one channel a clean one...
and maybe a line out for recording... though i might just add that to the practice amp...

although if I could use a similar circuit design for what would effectively be one of my channels on a quieter scale that would work awsomely!! is there a way to change values so that the schems could be used for both a 1w and a 100/200w?

Mainly looking for advice on how to proceed with schematics and the like as i've not seen much info about building that sort of sized amp... think the most i've seen is a 65w single speaker amp... and I also would like to find where to buy the power amp bits from cause i don't really want to be messing with stuff like that!!

Ideally what I'd like is to be able to build the circuit boards etc and add power supply to it rather than building the whole thing...

I make guitar pedals so can solder and read schematics... but i'm fairly new to the idea of building amps... this isn't gonna be sold so if it's a clone that's ok too... this is also to help me fix my own stuff as i've been ripped off too many times by people "fixing" stuff...

I currently use a Fallen angel 100w tube preamp combo and one of the channels has died so might attack that when it goes cause it's a nice cab!! it has a great tone but just a little too bassy and I get drowned out in practice...

any help much appreciated!!!

[pdf64]

See
Weber Speakers - Making the world a bit louder each day.
more specifically
https://taweber.powweb.com/store/kits.htm
for a lot of different kits at very good prices.
You get a complete package, with a finished cab, but can de-select varous parts though.
You will pay shipping, VAT, and agents fee (about £10 for administering the VAT) on top of the kit price, to get it into the UK.
The kits don't have detailed instructions, just a schematic and layout. So start with the simple one, use the forums and gain competence.
It would help if you already know what the inside of vintage tube amps look like, as tidy lead dress gets rid of a lot of problems.

[shugs81]

I kind of have an idea as when i was looking for kits I found loads of pics...

Will check those kits out... have also seen the doberman kits for the ax84 site...

looking forward to blowing my self up... i mean getting started...

[Wombaticus]

The Doberman/AX84 kits are a really good place to start -- all of those amps have been built a million times, and the AX84 forum folks routinely help newbs get their builds going. The P1-eX was my first build - you'll learn a ton, and it's quite a decent sounding amp in its own right.

[shugs81]

cool... i'm just waiting for my account to be approved so i can get some more info from them... may try to source parts myself as it may work out cheaper than getting the kits shipped over from the US... although with the exchange rate at the moment i may be wrong...

hopefully get the account ok'd today cause i'm itching to get started... I also wanna know how to increase volumes of kits... i.e. if i like one of the little amps how to mod the schematic to build a head / amp using the same tones but at a higher volume... more research methinks!!

[paggerman]

suggestion for a first build

Hi Guys,

I'm interested in building a 100/200w Tube amp... or possibly head and cab... minimum 2x12 mainly cause i got a knackered carlsbro glx150 with 2 celestion(??) speakers sat doing nothing!!

I'm looking to build a smaller practice amp first before I go for the main one (for the practice!!) and was also wondering if there's a decent 1-5w kit anywhere that isn't £600?

I mainly play heavy rock at the moment but I also like playing punk/ska stuff too and was hoping for something marshall-y in sound.
Not looking for any extra effects and I want 2 channels... possibly both exactly the same tones & gian stage so I can use different guitars and level them out through the channels rather than messing with volume pedals! one guitar is quieter than the other and the loud one's volume is pretty much on or off!!

would also be looking to have a footswitch too to switch channels...
and maybe a switch so that if i was only using one guitar i could make one channel a clean one...
and maybe a line out for recording... though i might just add that to the practice amp...

although if I could use a similar circuit design for what would effectively be one of my channels on a quieter scale that would work awsomely!! is there a way to change values so that the schems could be used for both a 1w and a 100/200w?

Mainly looking for advice on how to proceed with schematics and the like as i've not seen much info about building that sort of sized amp... think the most i've seen is a 65w single speaker amp... and I also would like to find where to buy the power amp bits from cause i don't really want to be messing with stuff like that!!

Ideally what I'd like is to be able to build the circuit boards etc and add power supply to it rather than building the whole thing...

I make guitar pedals so can solder and read schematics... but i'm fairly new to the idea of building amps... this isn't gonna be sold so if it's a clone that's ok too... this is also to help me fix my own stuff as i've been ripped off too many times by people "fixing" stuff...

I currently use a Fallen angel 100w tube preamp combo and one of the channels has died so might attack that when it goes cause it's a nice cab!! it has a great tone but just a little too bassy and I get drowned out in practice...

any help much appreciated!!!

My first build was a 'lamington' from Grant Wills (Valve Heaven - Home). This is a 15W push pull using 12AX7 and EL84 valves. This is a from scratch build, so there is no kit. My electronic experience to date had been a BYOC pedal and a 1/2 watt Noisy Cricket ss amp. However, by taking my time, following the circuit diagram very carefully and using information from this board I had a great learning experience and a valve amp that worked first time at a reasonably low cost.

I am now onto my third build and have acquired a number of old valve radiograms which I will use to build more amps. If I were to go into 100W territory I would take a very different approach, but I'm having great fun with what I'm doing.

How do they sound? A helluva lot better than any SS practice amp I've tried. But I'm learning to play guitar at the same time I'm learning about valve amps, so I don't really have any experience to compare them to. But I can always tweak 'em, cos I built 'em.

Good luck, and don't forget to bleed to ground your caps before poking around inside!

[shugs81]

My first build was a 'lamington' from Grant Wills (Valve Heaven - Home). This is a 15W push pull using 12AX7 and EL84 valves. This is a from scratch build, so there is no kit. My electronic experience to date had been a BYOC pedal and a 1/2 watt Noisy Cricket ss amp. However, by taking my time, following the circuit diagram very carefully and using information from this board I had a great learning experience and a valve amp that worked first time at a reasonably low cost.

I am now onto my third build and have acquired a number of old valve radiograms which I will use to build more amps. If I were to go into 100W territory I would take a very different approach, but I'm having great fun with what I'm doing.

How do they sound? A helluva lot better than any SS practice amp I've tried. But I'm learning to play guitar at the same time I'm learning about valve amps, so I don't really have any experience to compare them to. But I can always tweak 'em, cos I built 'em.

Good luck, and don't forget to bleed to ground your caps before poking around inside!

That's a good point!!! how do i do that????

[Wombaticus]

It sounds like you are on the same kind of trajectory I followed... I started off with a P1-eX (which is actually surprisingly loud), and have built more than a dozen since, none of which have been kits since the first one, and tending to increase in power and features. But only now with my current project am I attempting a truly high power head (I'm doing a build now with DNA obviously related to a 100W Marshall 1959SLP)... I haven't done one before not so much because it was too tricky or anything, but because you realize pretty quick that 100W is just insanely, stupidly, unnecessarily loud for 90% of practical situations (the SLP is a commission - I wouldn't build it for myself).

The bottom line is, unless you already absolutely know you need 100W and play in really big venues or outdoors a lot, you'll probably find that a tube amp around the 25-40W range is more than adequate for keeping up with a loud drummer and playing club gigs. The 100W amps don't even really start to sound right until your ears are already bleeding, and a lot of times even 50W is too much.

By the way, since you seem interested in getting into the design aspect of amp building, while you're waiting for kits/parts to arrive, you can start boning up on some theory - the best place to start is the "Valve Wizard" site:

How to design valve guitar amplifiers

Especially read his free chapter on the triode gain stage... it is very well written, and will make a lot of stuff make sense.

[paggerman]

little bleeder

If you're buiding it yourself, put a resistor (between 220k and 1M) in parallel with the first filter cap - this will self discharge on power off. Otherwise, use a croc clip with a resistor attached - lots of shrink tube to add strength - and an insulated probe on a fly lead. On power off, clip the croc to the chassis and then put your left hand in your pocket. Then use your right hand to touch the probe to the +ve side of the filter caps until all those lethal volts have drained away.

[Gibsonman63]

The guys are correct. 100 Watts can be insanely loud. I am currently building an attenuator for a 35Watt amp that is too loud. (just ask my wife!) You and your audience will be better served by putting the big power into the PA and keeping the stage volume down. With 100 Watts of stage volume, you will have a hard time getting the vocals up where you can hear them through your monitors without cutting so many frequencies out that they sound horrible to you. Most of the frequencies that bring out clarity in the vocals are the ones that will feedback.

Read everything you can on tube amps and lead dress before you start. To discharge the caps, ground pin 1 (usually). Here is a more exhaustive discussion on safely discharging capacitors:

http://music-electronics-forum.com/t10911/

Remember, you will be working with lethal voltages, so if there is any doubt whatsoever, check with your meter first.

[jreese2001]

safety cannot be stressed enough. i would use the best practices posted on this forum to come up with a checklist to go through everytime you start working on the amplifier. post it clearly in your workspace and make sure to go through each step before touching anything inside the amp.

things like forgetting to unplug the amp from the wall (even if the switches are off) are easy to do and have a good chance of leading to lethal consequences.

Get into the habit of checking the voltages with a multimeter before touching anything, EVEN if you remember discharging the caps, EVEN if the amp has been sitting there unplugged for a long time.

it is worth it to be paranoid about this kind of stuff

[shugs81]

will do... i don't ever leave amps plugged in... i don't leave much plugged in apart from tv and pc...

will deffo do a checklist.... may even leave it inside the amp!!!

[shugs81]

I'm planning to build a couple of amps before going to the 100w stage...

my current amp is a 100w ss with tube pre amp... what wattage tube amp would compare with that.... we do get rather loud like... and we don't use monitors... lol...

[Gibsonman63]

A lot has to do with speaker configuration and effeciency and everybody knows that tube Watts are bigger than transistor Watts I am running a 1985 Marshall 50W tube combo and it has been more than loud enough to keep up with anything I have thrown at it. I just completed a 35 Watt TW Express build over the weekend and seems louder than my 50 Watt combo. For a tube amp, you want to build small enough that you have to push it hard to get into the power tube distortion. It will not be linier like a solid state amp, it will have a sweet spot and once you find it you can play right on the edge and push it into overdrive and then clean it up with just your pick attack and the volume knob on the guitar. If your sweet spot is too loud to be usable, then you will be doing tricks like power attenuators and pulling a couple of power tubes to make it work.

Doubling the power only increases the volume level by 3dB, which is not very noticable.

Don't get me wrong, I love the sound of a 100Watt full stack, but you have to have a lot of stage to pull that off. I ended up using half stacks back in the day becuase I got tired of hauling the second cabinet and then having to unplug the top one so I could hear the rest of the band... but if you have a big enough stage and enough guitar cable it can be a lot of fun.

[shugs81]

not quite at that stage yet... lol...

might aim for 50/65w.... explains why there was loads of schems for them and non for 100w... lol...

for a 2x12 is that the sort of figure? 50 - 65w?

thanks for all the help peeps!