Looking For a Discrete 50w+ Guitar amp schematic useing Parts I have???

[Minion]

Hi Folks, I"m new here and this is my first Post ...But I am not that new to DIY Electronics as I have built a couple Guitar amps useing IC"s and have built many Mic preamps and Stompboxes and a few Gainclones other music related audio curcuits Pluss my Guitar is a heavilly Modified Ephiphone......

The Guitar amp I use now is a 50w one Based on a LM3886 Power amp IC and a discrete J-fet Preamp stage with tone controlls and 2 Different Overdrive stages which are user selectable....This is a fairly Loud and extremely heavey sounding amp but I now want something with a bit more Power and with a cleaner output ,Something that I can play shows with as my 50w one is loud enough but at that Volume it is hard to get a clean Tone out of it .......

I happen to have quite a few Transistors that would be suitable as output stages and have a couple good Power Transformers (30v,0v,30v-200vA) that should be adequate for building an amp in the 75w range and I have lots of Parts but I am haveing trouble finding a suitable Schematic/Project that would utilize the Parts I have available so I am here to ask you good Folks if you could maybe point me in the right Direction.......

Here are some of the Transistors I have:
MJ11016/MJ11015 30A 120v 200w To-3 Darlingtons
MJE3055/MJE2955 70v 10A To-220
Tip31C/32C 100v 5A To-220
Tip41C/42C 100v 7A? To-220
BD139 80V 1.5A SOT-32
BC550C/560C 50V 100mA T0-92
2N4401/4403 40v 600ma T0-92
2N3904/3906 T0-92
2N2222A T0-92
IRF630 200v 9A N CH-Mosfet T0-220
RFP8P08 80v 8A P-Ch Mosfet  To-220

And I have some Various other Small signal Transistors and some J-fets and all the Caps and resistors and PCB material I need, or at least for the most Part......

So if someone knows of a Guitar/Bass amp project that will utilize the Parts I have or even a Power amp stage that would be awesome.......

Thanx a Lot.....

Cheers

[teemuk]

In practice it's pretty hard to find a design that would fit exactly your parts list but for example BD139/BD140, TIP31/TIP32 and MJE3055 are transistors that are used in numerous designs.... for example, this one: http://sound.westhost.com/project27.htm ...and from the same site: http://sound.westhost.com/project03.htm

With little modifications you could make almost any circuit to suit those transistors. Maybe you should start by googling for "50W amp", "50w MJE3055" etc. and see what you can find...?

tip: the "picture" search option in google is usually more helpful.

You also didn't tell what features you are looking for to have?

[Minion]

Hi, I have allready considered that Project , But don"t have the right Parts (I guess I could replace the BC549/559 with the BC550/560 but I don"t have any BD140 but maybe I can use a BD139 and switch the Emitor and collector or maybe just use the Tip31/32??)

I actually don"t need any special features accept it being clean and loud as I can allready design the Preamp stage with overdrive and tone controlls useing Ic"s.......


Thanx

[teemuk]

maybe I can use a BD139 and switch the Emitor and collector

NO! You are confusing two things. Transistors can be "reversed" this way but it doesn't change their polarity. It just reverses junctions - which are usually asymmetric enough to render the transistor pretty much useless in the "reversed" configuration.

If you want to convert a NPN transistor to PNP you need another PNP transistor to form a Sziklai pair out of the two. Unfortunately, it will likely have too much gain in the considered application and you need to substitute the BD139 with a Darlington (or Sziklai) as well to match. Yes, this often means redesigning the output stage - at least on some level.

I suppose you have a reason why you can't just buy a bulk of those missing transistors. In my opinion you will - at some point - need them anyway since they are the complementary for BD139.

[Minion]

Hi,The reason I don"t ahve any BD140 PNP"s is because were I live there is only one electronics store and it has very limited selection and everything is about 20X the price of what I would find on-line but If I buy on line I have to pay huge Shipping fees which are generally at least twice the Price of the order for such small quantities.....

I get a lot of my Parts from dismantleing broken or obsolete audio and Video equipment so I usually just make do with what I have.....


Thanx