Guitar amplifier project

This page shows a few pictures of our guitar amplifier project.
If you play through an external preamp / effectunit, you are in need of only power amplification and aren't in need of more preamps.
Our guitar amplifier accept a balanced line level dual channel (stereo) signal and will not colour the sound except for the response
in the speaker cabinet and the speakers themselves (A pair of JBL E120).
Actually, the amp was tested by the Swedish guitar legend Janne Schaffer!

We can do all kinds of custom built amplifiers or modifications. If you got an idea of something you
would like to realize, contact us and we can support you in development and building of the amp.

The amplifier will output 170Watts RMS per channel into 8 ohm loads in stereo configuration.
The frequency response is well beyond 10Hz - 30kHz. THD is about 0.02% (1kHz)
The amp operates in class AB and has a total supply filtering of 6 x 4700uF (28200uF)

The following pictures will give a detailed explanation of the unit.
If you've any questions regarding this project, don't hesitate to mail us at:

Front view of the amp. The cabinet is made of plywood. There are handles on both sides and
wheels for easy transportation. No way to see this is a powered speaker cabinet!

Back view of the amp. Amplifier heatsinks to the right.
Combo input jacks accept both XLR and 1/4" plugs. The inputs are electrically balanced.
Speaker output jacks - used if the internal speakers aren't enough or you want to use 2pcs of 4x12" speaker cabinets.
To the left there's a panel with fuses, level attenuators and mode switches.

The panel. What you can see here is the mains power switch. One primary mains fuse and 4pcs of secondary rail fuses.
Output level can be adjusted by the level attenuators. One switch is for selecting mono or stereo mode operation.
The second switch is for selecting internal or external speakers. The yellow leds indicate the status of the protection circuits.

The power transformer is placed in the bottom of the cabinet for mechanical stability.
The transformer is slightly oversized providing 600VA.

Secondary rail capacitor bank 6 x 4700uF. This provides high transient energy increasing the burst power of the amp.
I can admit the bank was somewhat oversized. But it does the work brilliant.

Balanced inputs. The input board uses the high performance circuit "OPA2134" for providing
very high common mode rejection ratio, low noise and low THD.

A view of the entire amplifier panel. Amplifier boards to the left.

I use the amplifier together with a BOSS GT-8 preamp / effect unit.
The BOSS unit outputs line level stereo signals directly to the amp.

If you've got any questions regarding this project, or want to buy one of those amps, you're welcome to contact us.

Our goal is to reply within 24 hours!