Hi,

Right well i have breadboarded the English channel and am waiting for the guy from runoffgrrove to supply me with biasing value for 13.8v. I am now back to the idea of the acoustic  pre amp an dand getting a little confused. i guess the main issue is that 90% of the preamp circuits i find are for split power supplies and so i get worked up about how to run them, i realise with a couple fo resitors i could create a +/- 6.8v setup but then how does this work connecting to other parts in setup, this them my ground is actually 6.9v? that stuff always confuses me.

This seemed like a good starting point :-

http://www.headwize.com/images/eq3.gif

Any thoughts?

To be honest i went with the English channel for the decent tone controls which i think would be important for my mate.

Teemuk what value would i need for the replacement pot, i know the resistor is 10k but would that mean i should go for a 10k pot or a 20k lin so it is 10k in the middle?

The breadboarding is going pretty well, almost done.

Thanks very much, I am building an English Channel today on some breadboard but i will take a look at all those options tomorrow. Thanks a lot guys you have really got me back into this project.

Brilliant!!!

This is exactly the advice I need, not being a guitarist makes the project that much harder since i don't know what sound I am after in a way. The guy mainly plays classic english rock from the 60's 70's (think Stones, Small Faces) but also some heavier stuff like Zepplin and Sabbath. Yeah he's got great taste!!.

Looks like my idea for the english channel would work for the electric side and the tl072 idea sounds perfect since i have got a few and also some tl071 as well. I had thought about dual preamp previously but didnt know if that was needed, so its good to sort that out. Do you have or knows of a circuit based on that opamp with tone controls?

I imagine that gel batteries are the same as SLA's. Sealed lead acid we call them over here and that is what i have to power the unit, a big 7 Ah one, should last a few hours considering the 90% efficency of the Class-D amp i want to use.

Thanks so much for all your advice,

Phil

Hi,

This is my first post on here and hopefully i can ask for people help.
Just so as you knowI am not a musicain at all, however I am very into DIY audio and have build countless LM3886, LM 3875 chips amps and also a fair few Class-D Tripath based kits.

I am building a Amp for a friend who is a guitar based busker in London.
The main issue is this the busking pitches have no power so everyone needs to use battery powered amps.
The best of these are the Crate Taxi /Limo series.
All use some weird Class-H Philips chip which is very unreliable for day to day use.

I am mid way through building a amp setup but could use some advice.

For the power amp module to maximise battery life, and in my opion sounds quality i am using a kit from 41hz.com. Jan kits involve a lot of SMT bits so arent easy to build but sounds great and are reasonably priced. I also love the Tripath sound and think it would work very well with live music.

What i wanted to ask was advice on the preamp side of things. I have looked at loads and loads of sites and to me this is the hardest part particualrly when runnign of a single SLA battery.

What would be a good front end? My mate plays both electric and semi-acoustic guitar and would also needs a cd input for backing tracks from an iPod.

My idea was something like this an English Channel or Sans Amp GT-2 as a preamp, then an fx loop, and summing amp such as http://www.muzique.com/schem/mixer.gif to mix in the CD\ipod and finally a 41hz.com AMP 32.

Does this sound about right? Also has anyone got any experience with the English Channel or Sans Amp for use with an acoustic guitar?

I have no experience and would love some advice.