Randall modifications

Prices for Randall mods are approx. 80-100 Eur (w/o shipment), it  depends on many factors, mainly on elaborateness.

Randall RD45

Cheap chinese amp sounds little bit sterile, but 4rockers preamp modification changes it to typical metal machine with good sound profile for typical metal backings. (v. 4/2016)

Randall RH50T/RG50T

This cheap amp is too sterile for our taste. But we can make sound with more punch in the middle, better for metal players...

Orange mods

Oranges can be modded by many ways... They are good, but sometimes guitar player need more accurate sound.

Prices for Orange mods are approx. 80-100 Eur (w/o shipment), it  depends on many factors, mainly on elaborateness.

Orange TH30 mod

This mod is mainly for metal players: better bass response (more precise), more bite and aggression in the midrange, better reaction on player's fingers, better soloing... There are two TH30 mods at this moment - with big differences in sound...

Peavey mods

Peavey line covers all music styles, from country and blues to higain metal amps. The typical task is mod of higain amp (like 5150), because it sounds good while playing standalone, but often is too fizzy or his overgained sound is deleted by another amp in the band. We can mod preamps to give more meat&balls to sound of these amps, change power amp settings etc.

Prices for Peavey mods are approx. 100-130 Eur (w/o shipment), it  depends on many factors, mainly on elaborateness.

Peavey Valveking

Valveking is based on Classic line, it's better to mod this amp for hard&heavy... This is huge mod on both preamp and power amp, but amp is ready to rock after mods...

Peavey 5150 II

Here you can hear one short video from my job on 5150 II. This amp is copied in Bugera line  626x, just visit Bugera section on this website to hear differences from original sound. I cannot add original sound before mod due to my error, when the original sound was distorted by camera. This video was taken after preamp mod, so you can hear less fizzy sound, not so overgained.

Engl modifications

Engl's are perfect for heavy German backing sound, but sometimes so sterile for singing lead sounds. 4rockers mod gives more fat&juice to original sound.  It's a pleasure to play screamin' leads after mod on these amps...

Prices for Engl modifications are approx. 80-100 Eur (w/o shipment), it  depends on many factors, mainly on elaborateness.

Engl Thunder - v4 2016

New improved version of 4rockers modification of small Engl. Almost new 4rockers preamp. From clean through old school rock to punchy higain metal sound in the small box...

Engl Thunder - v3 2016

Brand new development, huge preamp modification for famous Czech rock player. The sound is much more meaty, not so tight as original Engl sound.

Engl Thunder (e325)

This little combo amp is a "poor boy" in Engl's product line, but we can start singing of this amp. It's a big change when you play sterile original sound and then you try some Gary Moore's riff on modded amp. Now depends on you: your amp is ready for classic screaming lead rock.

Tube amp mods

Our amp mods change boring factory amps to singing musician friends. We always try to dig a soul from amp and we want change reaction on player's style changes. We mainly want to create fat rock sounds with warm singing leads - that's our idea to leave tube amp sing your soul and brain through your fingers, guitar and tube amp.

Of course the best for mods are amps with full tube signal paths, but ask us with your specific demands.


We modded a lot of amp from Marshall, Engl, Mesa, Bugera, Peavey, Laney etc. Every time we want to find solution somewhere on the crossroad of your idea and technical possibilities of your amp. You can hear some examples of our mods on our pages or on our YT channel.

Select from amp's mark from the top menu. We can create your specific mod for known amps or for your different amp.

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