Modifications - Good or Bad?

   Modifications have a sometimes deservedly bad reputation, but can also be the difference between an amp that works for you and one that doesn’t. There are many examples of poorly conceived and even more poorly implemented modifications that have come through our shop. We have seen mint "Tweed" Fender Bassman amps with holes drilled in the front panels for master volume controls and wiring that looks like it was soldered with a blow torch; circuit changes that hum, buzz and oscillate; 1950s Les Pauls routed out for vibrato arms and worse. Who would have done these things? We ask that question ourselves! Just because a client asked for something isn't necessarily a reason to do it (though that's all the reason some shops need). What we try to find out is what a client wants to achieve and the best way to achieve it. Perhaps it would have been a better idea to trade in that old Bassman for a Marshall 800 at the time, but that option wasn't offered because it would have resulted in the shop losing a profitable job.

   Our primary solution is to help educate our clients. Advise them of ALL of the available options. Discuss any alternatives, and the best long term, cost-effective route to take. Sometimes, we have succeeded in this by refusing to perform some mods a client thought they wanted. By taking the time to explain the implications and the "bigger picture," it may be possible to find the better option.

   Do we modify equipment? Sure we do! But first we take the time to design the appropriate solution, and then implement it to a higher standard than that of the original equipment build. There are always several ways to go about doing a modification, and the easiest way is rarely the best. In electronics, everything is a trade off to some degree, and there's no free lunch. For example, if you want more gain from a circuit, you have to pay for it with a more stable power supply and better decoupling. It's not always just a matter of changing a component, because nothing happens in isolation. Everything is affected by everything else. The key to a successful modification is in the planning, design and execution. We have well over 25 years of experience with this and know what works and what doesn't.

Analog Bros. Modifications

   First, what we don't do: We don't modify any amp or other piece of equipment that isn't working properly to begin with, or needs some type of repair. We don't drill holes in front panels or ruin the aesthetic in any other way, we don't overload marginal power supplies or do anything else that will adversely affect the reliability and safe operation of your gear. We don't learn how to do a mod on a client's amp; all of the mods we do have been tried and proven on our gear first.

   What we do is use our discretion and knowledge to give you the best advice possible as to what you can realistically expect from the equipment you have. This will assist you in making the best decision on how to proceed. We always return all removed parts and perform all changes so they can easily be reversed in the future. This protects the resale value of both modified and stock equipment.

   We have found in some cases that by evaluating the condition of an amp, no modification was really necessary. By repairing a defective power supply or replacing a leaky coupling cap or weak tube, the tone of an amp that had deteriorated slowly over time was brought back to a degree that the client had forgotten existed in the first place. This is particularly true when an older amp is purchased and fails to live up to its expectations. Many times the client believes that it must need some type of modification, when it all it needs is some routine maintenance.

Types of Modifications

Safety/Reliability

   Unless we’re doing a 100% “museum” restoration (meaning NOT ever to be played), we always change the parts of the amp that can have an adverse effect on safety or reliability. We really don’t consider these modifications, though some purists may. This can be quite a source of discussion and conflict in come circles. If you plan to play the amp, it MUST be safe, and hopefully reliable. If that means removing the two-conductor mains cable and disconnecting the “ground” switch, so be it. Increasing the current or voltage rating of a component is also not a mod in our way of thinking. It’s just helping to keep the amp working night after night.

Performance Enhancement

   This is our favorite type of modification, and the type we do most often. It typically involves changing some component values, types or minor re-wiring to increase gain or change tonal response. There are some amps that were “almost” there in terms of tone, but need just a little help to bring them to full potential. One of the most common examples of this is the Marshall JCM 800 series. The early versions were among their best-sounding amps, but for the “ice pick in the ears” high frequency response. Subtle circuit changes result in a smooth and natural tone. Small increases in gain are added, along with some increase in power supply capacity. Every client we’ve done this for feels that the end product is what should have come out of the factory in the first place.

   One of our specialties is tonal sculpting. This is a re-voicing of the amplifier to better suit the client's individual requirements. Most manufacturers have to produce amplifiers that will function well with whatever guitar or player plugs into them. In the early days of amplified guitar, many manufacturers expected (and designed for) the use of their guitar along with their amp. Interestingly, players found otherwise. Plugging a Gibson Jr. into a Fender Deluxe resulted in a much thicker tone due to the higher output of the P90 pickups! Our services offer the advantage of melding an amplifier's characteristics to the guitar/pickups of choice. Be it more or less gain, headroom or any different tonal response, we can work with each client to produce the best, unique individual tone possible.

   Some examples of very common “tone mods” are converting amplifiers to older versions (like a silver to "black panel" or "tweed" spec Fender), altering the response and/or gain between multiple pre-amp sections, adding reverb to a non-reverb channel, etc.

Feature Additions

   To be honest, we really don’t do this much anymore. There was a time (not all that long ago, it seems) when the obvious “classic” amps had emerged and much of the rest was relegated to rehearsal, backup or major surgery. Fender brown- or black-panel amps were had for a hundred dollars or so, silver-panel versions almost free for the taking. Metal panel, four input Marshalls were being used as secondary backups for JCMs. We used to do a bi-monthly run to all of the area music stores. Driving around in the Blazer with a small pile of cash, by the end of the day we’d end up with an entire truck full of these “old trade-in” all-tube amps and not too much less cash! Who could have predicted this crazy future we’re now living in?

   Adding features (reverb, FX loops, gain stages, channel switching, etc.) generally requires significant alteration to the entire amp, with relocation of controls, major power supply upgrades and complete alteration of internal layout and wiring. To be honest again, yes, we did many of these here. Though our craftsmanship was outstanding in execution and the results were always quiet and reliable, it's no doubt these extensive modifications resulted in some amps that became difficult to sell or didn’t maintain the resale value of the stock amplifier. Keep in mind that this was before some of these features were commonly available, and that our clients did get many good years of use from them. To many potential buyers a significantly modified amp is an unknown commodity, while some comfort can be taken knowing that the stock version is at least “what it is”.

No Mods Here!

   There are quite a few newer amps by Fender, Marshall, Mesa, Peavey and others that, due to specific manufacturing techniques, poor design or other limitations, just are not good candidates for ANY type of modification. Unfortunately, these amps just “is what they is” and you either like them or not. They would require far more work than would be reasonable for the amount of increase in performance gained.

Current Problems or Future Solutions?

   The introduction of the factory “re-issues” may provide a source of “raw materials” for some (very) extensive modifications in the near future. Most of these were re-issues in cosmetic terms only and not built to anywhere near the same standard as the originals. It's unlikely that they will have much if any value, as they continue to degrade over the years. Due to factory money-saving construction techniques and poor quality parts (REALLY bad quality PC boards, awful IDC ribbon connectors, open frame potentiometers, etc.), they are not candidates for much, if any, improvement as is. They may provide a source of chassis, enclosure, transformers, etc. for all new circuitry and perhaps great tone. This type of “mod” would essentially entail building an almost entirely new amp and certainly would be a time consuming and expensive endeavor. For now, it's just something to think about. We haven’t yet worked up any formal designs or plans, but if this seems intriguing to you, let us know.



   We’re always open to discussing your ideas and seeing if we can provide a solution. Not everything here is written in stone, but it should be taken as an overview of our philosophy. Our experience has shown us what has worked out well and what hasn’t.