Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: thickstraps on March 22, 2018, 08:16:40 AM

Title: Use small amp as overdrive for another amp
Post by: thickstraps on March 22, 2018, 08:16:40 AM
Hello,

I bought a small 30w 'gorilla' amp, it's awful. I plan to use it as a nasty sounding pre-amp and overdrive/distortion for some of my home made instruments.

I hope to do two things,

1. use standard pedal power supply instead of mains and
2. run the speaker out into my mixing desk.

So I wonder if I might utilize the hive mind to help achieve these humble objectives

I have no schematic and cannot find one, I have some experience of pedal builds but no particular electronics knowledge beyond the basics.

1. should i just ignore this step all together? Maybe it's not a problem to run this ting off mains voltage? There is of course a transformer on the power input, where do I measure the output voltage of this? Just shove my probes onto it's outs? What's voltage likely to be here?

2. What can I do to modify the speaker out as a line out? I have seen plenty of simple reistance networks that purport to do this, is it really that simple?

Any advice gratefully rec'd

thanks in advance
Title: Re: Use small amp as overdrive for another amp
Post by: phatt on March 22, 2018, 09:30:31 AM
Re q1/ No bad idea xP
Pedal power is only 9VDC,, the amp will likely run at much higher voltage.

Re q2/ Yes a 100k series resistor into a 10k pot to ground will give you a hot line level output.
You can do this in a small jiffy box outside the amp if mains voltage worries you.
You can leave the speaker connected which may improve the outcome but try it both ways, with and without speaker.
The basic idea is to split the output with a 10/1 divider, the pot allows you to find the best balance. if it's still too hot for the mixer input then use a 220k series resistor or solder a 10k resistor across the 10k pot.
Phil.
Title: Re: Use small amp as overdrive for another amp
Post by: Enzo on March 22, 2018, 04:36:53 PM
Try contacting Pignose and asking for the drawing.  Pignose owns the Gorilla brand.

https://pignoseamps.com/pages/contact-us
Title: Re: Use small amp as overdrive for another amp
Post by: thickstraps on March 23, 2018, 05:42:31 AM
thanks everyone, very helpful

phatt - regarding pedal power - if i measure power transformer at it's output and it's say somewhere between 12 and 18v i can swap out the mains for batteries at least, no?

and regarding line out

really does seem that easy, thanks a bunch!

Enzo, thanks, emailed today, hopefully they'll come up trumps.
Title: Re: Use small amp as overdrive for another amp
Post by: phatt on March 23, 2018, 07:38:44 AM
Are you measuring the AC voltage at transformer secondary or the rectified DC Voltage?

You also need to establish if the circuit is single or split supply.
If it's split (+/-) then you would need 2 batteries.

Either way if the Amplifier does pump out 30Watts into an 8 Ohm load then it will likely flatten batteries fairly quick.
Phil.
Title: Re: Use small amp as overdrive for another amp
Post by: Jazz P Bass on March 24, 2018, 08:30:42 AM
" 30 watt Gorilla amp"

Can you provide the actual model #?
Title: Re: Use small amp as overdrive for another amp
Post by: thickstraps on March 27, 2018, 06:48:50 AM
Quote from: Jazz P Bass on March 24, 2018, 08:30:42 AM
" 30 watt Gorilla amp"

Can you provide the actual model #?

Hello,

gorilla GG20, wretched piece of rubbish, but with a horrid harsh distortion that suits me very well.
Title: Re: Use small amp as overdrive for another amp
Post by: WB on March 27, 2018, 05:29:16 PM
Have you tried using the headphone output in conjuction with the master volume for a line-out?
Save some work.