#1
Hi guys,

It occurs to me that I haven't posted about my home made valve amp yet, so here goes...

Summer last year (2007) I decided to build a valve amp, so I set about finding designs, and ended up sourcing most of them from this site. Its an amazing place to learn about amp designs and to build your own. But I live in england, so I didn't really want to order all my parts from America, so that was the next step for me.

It must have taken me about 3 months to track down all the parts and order them, but I did, and building commenced. I reckon it took me 4-5 months to finish the chassis (everything except the box), with the only error being me getting the negative feedback loop the wrong way round, which is the amp making a howl as loud as it possibly can, which at 25 Watts of valve power, is enough to scare me ****less! Found out on ax84 its a 50/50 matter anyway, unless you know exactly what to test for, and nothing was damaged.

When it finished the amp worked first time, which is nothing short of a miracle for me. The only thing wrong with it was the treble being a little feeble, and that was easily remedied.

The beauty of building something yourself is you know exactly what is where and how to change it. Fully customizable.

It is only recently (feb 2008) that it is nearing full completion:

Chassis only:






Most of my "rig":



Point to point wiring (i.e. no circuit boards) is one of reasons my amp isn't noisy:



Thats one 'effin' huge resistor!:



Wood stained outer box:


stained back panel:



Stained an polyerethene varnished front panel:






Still needs some work as you can see, but its getting there...
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#2
cool.
what schematic from ax84 did you follow?

I've been researching info. about building a HO with the kit from dobermanamps, but I still don't think I'manywhere near ready .....
#3
it was the lead preamp with the 20WPP power amp, but with adjustments here and there. I would warn you, this takes a hell of a lotta work, and money. The parts alone cost me £230, and thats not counting the metal working tools and high voltage test gear. Also these are very dangerous. I have an electrical engineer for a dad, so he could watch over me, but the voltages inside valve amps incur instant death, no ifs, buts or maybes, because its at 350V instead of 240V.

But you will be rewarded, mine sounds great and is easily customizable. You get a real sense of achievement aswell, and the ultimate in boasting opportunity!
MIM Tele
Yamaha Pacifica 112
Marshall ED-1 Compressor
Morley Power Wah
Boutique booster
Digitech Bad Monkey
Electro Harmonix Small Clone
Electro Harmonix #1 echo
THE BEAST (head)
Line 6 Spider II head
D130F
Greenbacks
#5
^Yep, noise comes mostly from bad lead dress, and I'm surprised yours isn't noisy tbh. You have wires going all over the place. But if it works and sounds good i guess it doesn't matter.
Call me Roche.

Quote by Dyers
wut is a luthier? im assuming it has to do with the luthern church
#7
Nice job for your first time! I hope you had fun and learned a few things as well. Building amps, as well as just playing with electronics, can become addictive.
#8
Quote by blub man
I have an electrical engineer for a dad, so he could watch over me, but the voltages inside valve amps incur instant death, no ifs, buts or maybes, because its at 350V instead of 240V.


Voltage is irrelevant. I'd rather grab the B+ than the heater wiring.
#9
Volts isn't what will kill yah. It's the amps. Thus is why hankey would rather grab the B+ then the heater lol.
#10
^its the current that flows in you that kills sort of. mostly, it's the power dissipated by the current flow, which is power (watts) and that's current x voltage.

but i don't know what power B+ or the heater wiring would dissipate...
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.


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#11
Quote by ECistheBest
^its the current that flows in you that kills sort of. mostly, it's the power dissipated by the current flow, which is power (watts) and that's current x voltage.

but i don't know what power B+ or the heater wiring would dissipate...



well this is true... but the amps do most of the damage. See voltage is just in very very low terms. The push. It's the amount of force making the current move. With out it, it wouldn't move. So you do need both. But the amp's will hold you to the circuit, and also is what will kill you ultimately. I believe the amount of current to stop the human heart is around 50mA if not less. I believe less, but I can't remember the exact number.
#12
voltage is the difference in the electrical charge between two points. if one point (the B+ wire in this case) has higher voltage (more charge -) than your hand (which probably has some charge, but not as much as 120V in the US), current flow occur.

current is the speed that one coulomb of charge moves per second. that said, current and voltage relates to each other when talking power (watts)

power = current x voltage. so if you have low current but high voltage producing less than 300mW(?) then it won't kill you. (i believe somewhere around that is lethal for human...) so lets say voltage was 300V.

for a voltage 300V, to reach 300mW of power dissipated, u need 1mA of current. but if the voltage was 1V, to reach 300mW of power u need 300mA of current (0.3A).



oh btw, mythbusters went over this matter (kind of) as an electrical appliance in a bath tub type of myth.
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
#13
Quote by WickedBeast666
well this is true... but the amps do most of the damage. See voltage is just in very very low terms. The push. It's the amount of force making the current move. With out it, it wouldn't move. So you do need both. But the amp's will hold you to the circuit, and also is what will kill you ultimately. I believe the amount of current to stop the human heart is around 50mA if not less. I believe less, but I can't remember the exact number.


I believe it's as low as 15mA.
#15
http://www.pseg.com/customer/home/safety/myths.jsp

Just because that annoys me...
see, I've gone to college for this, and I know better then to think volts kill. Mythbuster's are not electrical engineers. See, If it was watts that killed, then static electricity would make one hell of a death sentence for everyone, considering it pushes well over 3,000 volts. Just for you to feel the little poke.
#16
Quote by mr_hankey
I believe it's as low as 15mA.

That's how much current it takes to induce a hold on someone, not lethal until you are stuck on it for a longer period of time. I believe around 50mA is when it is lethal within 1/2 of a second.
#18
Quote by WickedBeast666
See, If it was watts that killed, then static electricity would make one hell of a death sentence for everyone, considering it pushes well over 3,000 volts. Just for you to feel the little poke.

watts kill because electricity is lethal when both current and voltage is there. extremely low current + high voltage or extremely low voltage + high current won't be too harmful. that's my point. i think i'll go pull out my electric circuits book from my car.
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
#19
Quote by ECistheBest
watts kill because electricity is lethal when both current and voltage is there. extremely low current + high voltage or extremely low voltage + high current won't be too harmful. that's my point. i think i'll go pull out my electric circuits book from my car.

but even on your wikipedia posting, it basicly said all the death parts by current. You just need voltage to introduce the current into your system. Didn't say how many watts you need to cause death. It said how many mA which is AMPS Which is Current! Yah you need voltage to get past the resistance of the skin, I'm not denying this, but the voltage isn't causing the lethal parts.
Though I don't like wikipedia much due to random idiots editing it to the way they like.
#20
^ i guess i need to go study again then.


the edits by random idiots are easy to see. and close to nobody edits so cleanly but false that i don't see 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
#21
Quote by ECistheBest
^ i guess i need to go study again then.


the edits by random idiots are easy to see. and close to nobody edits so cleanly but false that i don't see it.

Agreed man, that's why I can follow the parts when they when they are talking about ohms law, because they showed the formula's. But that whole part is just showing how many volts it would take to penetrate the resistance of the skin, and how many amps would follow to cause lethal shock. = watts.

but I do agree with you man, you do need both. Just the amount of voltage is less a factor after it's enough to get past your skin resistance. ... Though may not be much of a factor at all if you decide to bite onto the wire, thus having almost no resistance to shock due to conductivity of saliva... but if your doing that... well you deserve what's coming.
#22
How did I know this was going to turn into a voltage doesn't kill you thing.

Nice amp Ben, although I never realised how ridiculously untidy it was inside

Also, it is noisier than you make it out to be

And, it needs moar stain!
The Laney Thread are big and clever. No exceptions.
#23
WOW, leave a thread for 12 hours...

As for the voltage current thing, yes I know, but I was simplifying it down, and making it sound more scary really!

PCBs themselves will not contribute to noise yes, BUT you have to trail wires off over things you don't want to trail wires over, like the heater supplies for instance... I have researched this, and I found that using a PCB would lead to me trailing wires pointlessly long distances, and it would result in way more wires than I should need. Trust me on this, point to point is epic win!

Yes the wires could be shorter, but I left them long when I was building it just in case, and I have never got round to shortening them. Also, crossing wires at 90degrees if you cannot avoid crossing them is good, as this cancels out some of the electro magnetic interference.

Also, for some reason my camera makes things seem messier than they actually are (I suspect the flash)! And I'll thank you not to comment on my solder joints whoever that was, they're perfect!

Oh and Oli, considering the gain mine is often at at our band practices, mine is way quieter than your precious Laney

Plus there is a ground problem somewhere in my rig, not sure where...
MIM Tele
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Last edited by blub man at Feb 10, 2008,
#24
Weep, Ben, Weep:



Now that bad boy is damn neat.
The Laney Thread are big and clever. No exceptions.
#25
That is ****ing neat^^

But then it was factory made...
MIM Tele
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Digitech Bad Monkey
Electro Harmonix Small Clone
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Greenbacks
#26
Meh I guess.

But it's neat as.

You need more stain on it!
The Laney Thread are big and clever. No exceptions.
#27
The stain its good

The gazillion layers of varnish will darken it up and make it shiny as kenty babes's bald head! (injoke)
MIM Tele
Yamaha Pacifica 112
Marshall ED-1 Compressor
Morley Power Wah
Boutique booster
Digitech Bad Monkey
Electro Harmonix Small Clone
Electro Harmonix #1 echo
THE BEAST (head)
Line 6 Spider II head
D130F
Greenbacks
Last edited by blub man at Feb 10, 2008,
#28
Quote by blub man
That is ****ing neat^^

But then it was factory made...


Even more reason for you to do it better! They don't take it slow in the factory. You can.

AFAIK, there are no more companies that make PTP amps. It doesn't really have any major advantages over turret/eyeletboards (noise is the only one I can come up with, which depends more on layout and lead dress anyway), just disadvantages.
#29
Lul.

Also, is it Polyurethene or Polyurethane lacquer? Different things methinks
The Laney Thread are big and clever. No exceptions.
#30
A lot of planning goes into making a turret board, practically none into the PTP, and IMO the PTP method yields a greater noise-signal ratio.
MIM Tele
Yamaha Pacifica 112
Marshall ED-1 Compressor
Morley Power Wah
Boutique booster
Digitech Bad Monkey
Electro Harmonix Small Clone
Electro Harmonix #1 echo
THE BEAST (head)
Line 6 Spider II head
D130F
Greenbacks