Quote from: armstrom on September 08, 2008, 10:37:34 AM


1) Which end of the shield should be grounded? I know this is a generic question but I'm struggling with it. I know I should only ground one end of the shield to avoid ground loops, but which end? Lets say I'm running a shielded wire from my preamp board to a volume pot. Should the shield be grounded at the pot or at the board?

I tend to ground at the board, but it doesn't make any real difference. I'd go with whatever you find convenient.

Quote
2) How many leads for a mono 1/4" audio jack? Since the barrel of the 1/4" plug is ground, can I just connect the shield and use a single conductor inside for the signal (tip)? Or, would it be better to run two-conductor shielded wire from the jack to the preamp board with the ground and signal on shielded conductors with yet another connection to ground for the shield itself?

Just connect the screen to the barrel and the core to the tip. That'll work just fine. Try to ensure that the jack is isolated from the chassis to avoid ground looks though. The plastic sockets are best for this.

Rgds

Martin

Thanks for the welcome. I did read and the specs, and I probably didn't make it clear in my original post that I wasn't expecting to run it flat out but the 100w rms would have given me plenty of headroom, allowing any distortion to come from the pre-amps and be under control. Anyway, given the comments I've decided to abandon that path, unless desperation sets in.

Part of the attraction of a kit or module, at this point in time, is that I'm looking to get something together for a gig (my first) at the start of November. I don't want to spend a lot of time building and tweaking if I can help it. I'd rather be getting on with practicing. I do have an 18 watt lite, which might have done the job if it wasn't for the one track where I need to play clean, hence my investigation into ss amps/modules.

I've been considering using one of the ROG circuits as a pre-amp into a PA driving my guitar cab, not sure how well this would pan out but I may well give it a try in the near future. Has anyone here done something similar?

Regards

Martin

That seems like quite a strong no for the Velleman kit, with some good reasoning behind it.

The LM3886 chip looks interesting, however the kits mentioned are not UK based. (I'd prefer a kit, but it's not essential.) Can anyone recommend a UK supplier?

Regards

Martin

Hi,

just found this site by googling solid state guitar amp.

I'm thinking of building an amp using the velleman 200w kit (http://www.velleman.be/ot/en/product/view/?id=360356 ) with a preamp based around one or more of the ROG amp simulations. I'd also like opinions on whether or not it would be practical to utilise it, with a different pre-amp, for acoustic guitar.

200w is way more than I need, but it's 100w in real money and that should allow plenty of headroom so the only distortion is from the pre-amp. I can get the module and transformer for circa £60 which seems cost effective.

If this isn't a good solution, can you suggest a schematic or better still a module around 50 to 100w RMS that would do the job.

The amp would be built as a head unit and would be used to drive a Celestion VIntage 30 and G12H30 in parallel at 4 ohms.

For those concerned about my abilities wielding a soldering iron, I've built 3 valve amps and more effect pedals than I have fingers to count them with. I know my way around a schematic and have produced my own PCB's, but prefer stripboard for one off builds. I don't want to sound as if I'm blowing my own trumpet and acknowledge the greater experience here, just trying to head off some questions.

Regards

Martin