The Amp Garage

Great, thanks for the advice guys! I'll give him those options to chew over.....I'm kinda hoping he doesn't get too set on me building him one, as I'm not 100% sure of how I made mine turn out as well as it has

Hi all I built an express style amp recently from an old Garnet pa - was a hit with my bandmates and one has asked me to build him a replica. I don't think that's possible because I'd never find the same trannys, etc again. But, he has an old YB1 Bass Master in good working condition. He doesn't lik...

Hi all Just wanted to post a couple pics of my completed amp, and say a big thanks to everyone who helped and chimed in with advice, along the way :D I went for a blonde simple cabinet look as all my other stuff is black :shock: rps20170517_111735_242.jpg rps20170517_111834_848.jpg rps20170517_11191...

I meant to write

V1 pin 1 298
V2 pin 1 388

I've checked for good voltages Can we start from the top? What are your plate, screen, and grid voltages? Ok I removed the b+ resistor I added, thought it might be choking things. Nice big sound now, clean and dirty from guitar volume - which was my big goal :D Voltages with amp on, no standby, vol...

Mike, It's hard to tell from your photo (not quite hi-res enough), but check that you didn't inadvertently solder in a 470k resistor for the bias resistor of your PI, instead of 470R. This happens sometimes and it usually makes for a very quiet amp. Just thought I'd throw out that idea before you g...

Do you have a scope? Or a listening probe? I'd recommend trying to find out where the signal is dropping to a weak level. You should see it at the input jack, then post the first stage, etc, and that should help you isolate where the signal is going so weak. As for the bias voltage, you need to cal...

in fact the idea that removing NFB makes it go silent is reinforced by that. You likely have it on the wrong phase so you have PFB (Positive FeedBack) and with that extra boost it gives it just enough to actually sound okay, otherwise it just dies out? Good eyes, Phil. That statement was so bizarre...

Thanks, here's a gut shot of the new build, I tried to tidy things up and work on lead dress more. Changed the layout to suit keeping heater wires away and power lines under boards with short signal wires over boards. It did mean altering the turret board layouts to orient components the right way a...

Could you guys listen to this sound sample? Warning: it's ugly :roll: [attachment=0]20170511_141832.mp3[/attachment] Ok checked the grid reference resistors, seems good -[/mp3] although I don't see a grid reference in the schematic for v2. Unless it's the 100k resistor before the tone stack, which I...

Hi all, I rebuilt my express prototype into a new chassis. Redid everything including boards, it fires up but is very low volume and bad blocking distortion type sound. Based on the Kelly 90 schematic from this forum. Hum is ok, it will play but cuts out on notes and this weird blocking distortion t...

Oh right, thanks for loading it on there!

Yes, Radiohead "lucky".

I used the Rob robinette TMB tone stack sketch, but I've got some wrong stuff going on - the volume works backwards and the tone knobs do weird things, including changing buzzing, causing hiss etc. Have to work on that.....

Thanks, hopefully I did this right. So I plugged the build into my home practice 2x12 cab, it's a fairly dark and dull cab (hence home use only), but the rig stopped smoking resistors anyway. Must have been that little car speaker, too much load or something. It ran fine, noisy beast at this point b...

What's the simplest way to upload or let people listen to an amp sound test? Mp3 file....

When you know the resistance and power rating for a resistor, and want to calculate for maximum current to obtain the resistors power rating, use this formula: P = I^2 * R Power (in watts) = I^2 (current squared) * R (resistance) The formula needs to be re-arranged to make it useful. By dividing bo...