Marshall amp modifications

Marshalls are typically very good for sound modifications. There are a lot of models with some problems in topology and sound creation, like dual channel amps from eighties. A lot of newer models play good backings, but a lot of them forgot to sing while soloing. We are able to return them back to singing leads.

Pricing for amp modifications differs and depends on difficulty. Standard price for typical amp modification like JVM410 or TSL60 4rockers modification is 100Eur w/o delivery price. We need approx. two days for mod and testing.

You can hear some of our modifications here:


Marshall JVM410

Marshall's flagship is a luxury amp with a comfortable switching, digital reverb, 12 presets for preamp etc., but not as good in creating lead sound on the same level. We changed some things in preamp to tune this amp for better backings, but mainly for singing lead tones. Forget over-compressed sound where all notes are almost the same!
We prepared 5 modifications, this amp can be modified in a different ways...

Improved version 5 - April 2016: better "classic" midrange punch, other as v4...

Version 4: 10/2015! Much better sound! Better crunch/OD1, classic 4rockers singing fat lead OD2!

Older versions:



Marshall DSL 50

This is "techno amp" and sounds sometimes too fizzy and withnout classic sound of overdriven Marshall.

New version of our DSL/TSL modification is very close to our JVM410 modified sound. No more techno sound from your amp!


2015: Our preamp mods (2 new modification types for 2015) return sound to pure classic rock sound... Check the video...



Marshall TSL60

New version of our 4rockers modification (5/2016)! We are happy that our TSL is on the same sound level as our JVM and DSL amps. TSL is real classic Marshall now.

Previous version: TSL60 is not a signing tube lead amp in original state (in the way we understand this term). We change the soul of this amp to play the lead role for soloing in the band. Now it's a bliss to play garymoorish solos... 2nd modification for this TSL60 is change of parallel fx loop to switchable serial loop. This is a often request, a lot of players ask: "While my sound is so weird when I switch boost in effect loop for solo?" There are no longer problems with phase of original and fx sound after our mod!


Marshall JVM205

Small brother of the JVM410 with the same problems as JVM410. We wanted to change this and to machine for experienced musician: better responds on player's style, better lead, better backings, no over-compression. Feel your attacks&tone.

New modification of JVM205 - v6 - 3/2017:

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Older version:


Marshall DSL401

Small combo with a lot of problems and hated by a lot of guitarists. But we can recreate new sound from this combo to use it for lead rock sounds, modern blues and similar styles.  The mod in the video was born for musician to play something like Walkin' by myself...

(wait a minute for video... just editing...)


Marshall JCM800 2205

This 2205 model belongs to JCM800 line, but is not as good as single channel 2203. The sound of both generations of 2205 is horrible for our ears. There are only few guitarists with good sound from this amp (like John Norum with his 2x 2205 from 2nd generation of 2205), but a lot of with really horror sound of 2205.  We think, that our total mod of 2205 is much better than both generations of 2205 and is on absolutely different sound level.







This is only small part of modificated amps, but you can feel the difference in the sound against original Marshalls. Ask us for more and possibility of modifications of any other amp!


Bugera modifications

Behringer's tube amps Bugera are good in terms of topology due to theirs originals. The best known Bugeras are not Behringer ideas, they are clones of Peavey amps. That's why our Bugera modifications are useful for Peavey amps also. Behringer changed only some parts, so amps have slightly different sound from Peaveys, but we can move sound to another level...

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

Bugera v55

Behringer declares this amp as a "design from sixties", but it not so clear. We made some modifications of these amp for jazz and rock. Here you can hear sound of redesigned preamp in this amp. It's - of course - our development (2/2016) as usual. You can use this amp as a rock machine after 4rockers modification:

Bugera 6260/6262

This amp is (almost) clone of well known Peavey 5150 I/II, but also with typical troubles of 5150: for a lot of users they could be more fizzy and with uncontrollable overdrive. We can change it to real rock machine with perfect palm-muted backings and distinctive lead sound.

5/2016: New improved version of Peavey 6505/5150 preamp (also for copy as Bugera 6260). New sound structure, no fizz or favour, better defined gain...

Previous versions:



Bugera 333XL

Behringer's copy of Peavey XXX with a little flour in the sound. We can improve sound in many ways: for classic rock players or for drop tunings. You have to communicate style of your playing, we can mod this amp in many ways. But for really hard players could be our mod of 6260 slightly better.


Bugera Trirec

This is behringer's (almost) copy of Mesa Boogie, but with some slightly different changes. Sound is too crispy, but we can improve this amp and tune it to much better sound.


Other tube amp mods

There are a lot of specific and sometimes strange requests on tube modifications. We can modify some Chinese products, old amps from Ex-communist countries, boutique amps or no-name made by amateurs.

Jet City JCA-50

This chinese amp was designed by Soldano and signal path evokes hot rodded Marshalls (aka Soldanos). Clients called to 4rockers with higain requests, less brittle sound. Check this video with first modification of JCA-50:


You can hear old legendary amp MV-3 from East Germany in the next video. Our mod contents super boutique parts, but also topology mod, where Matchless meets East Germany. Sounds awful for jazz players!


Rebuilding noname amplifiers

Maybe you have a noname old tube amp... not functional, demaged, but with OK mechanical parts... We can upgrade your amp to new level, insert new high quality boutique level parts. The result is perfect sound of almost new amp with lower price. Sometimes we hear here in 4rockers sentences like "Damned, this one has better sound that both my original old Marshalls from 70's!" (one client said this in August 2014)

Other boutique amp mods

A lot of amps could be repaired, modded, improved... There is no limit...



Another world are Chinese amps. Chinese engineers can calculate part values, but forgot to hear their products. We can mod these amps, but elaborateness is higher...

Ashton Viper VP100

Price of these individual mods changes piece by piece...


Laney modifications

Typical Laneys are based on Marshalls. Something like hot-rodded Marshall on steroids and we are often asked to remove these steroids. You can hear one modded Laney GH50L with different voicing in the next video, but we can change the sound in many ways.

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

Laney VC30

Client asked for repair and different sound on dirty channel, more as a classic rock sound like a AC/DC. This modification is new development of dirty channel of VC30.

Laney GH50L


Laney AOR 100

This is huge preamp mod, all preamp parts are replaced, new 4rockers preamp design.

Guitar effects modifications

We repair and improve guitar effects too, of course. There are plenty of effects, so here you can see and hear our mod of current "stock" Big Muff back to well known violin sound of older versions.

EHX Big Muff 4rockers mod

Prices for guitar effects repairs and modifications are based on type and state of each effect, because sometimes it's more archeological work than electronic circuit repair.

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