repairSince the very beginning, we have been making repairs and modifications of ESH amps as well as amps made by other manufacturers. To this day, we have helped thousands of domestic and international guitar players make their equipment sound either properly or, more specifically, the way they wanted it to sound in the first place. After all, not everyone is fully satisfied with the stock sound even when all seems to be working well. Many times, customers have been blown away with the result of our careful tuning, often saying that their amp never sounded that good, not even fresh from the box.
Making an amp sound its best in a part replacement or full restoration exercise requires deep knowledge. This includes careful selection of the tubes, exact setting of bias, and last but not least thorough familiarity with used parts' sound characteristics. We have that and more - the educated opinions of and sincere feedback from those of our loyal, demanding customers who are music professionals playing different styles.
Prior to undertaking work on an amp, we consult the player about the kind of music he/she plays, the guitar and other equipment he/she uses and the sound he/she is looking for. This helps us better understand his/her actual needs and allows us to determine which parts or tubes would be best to maximize the amp’s potential for the player.
We repair and modify instrument tube amps from virtually all vendors from around the world including Marshall®, Fender®, Mesa/Boogie®, Peavey®, Soldano®, VOX®, Rivera®, Ampeg®, Bogner®, Crate®, Engl®, Laney® and many others.


Generally, various vendors’ tubes are vastly different electrically, mechanically and sonically; also there is a lot of variance even among tubes coming from the same product line. Tubes can be (an often are) noisy, microphonic; they can hum, have insufficient gain, be poorly matched, deficiently burned-in or not working at all, even when sold as brand new. At the same time, every amp is different and even each tube position needs a tube with diverse properties. Hence, going to the shop, buying new tubes, putting them in and hoping for the best rarely works. Countless times, over and over again people fork out money and time only to learn hard that improper retubing will turn even the best amp into unreliable, poorly sounding hardware.
Retubing is the most common job we do given that it has to be done periodically on all tube amps, regardless of type and make. We use only the best tubes on the market today, which are then at least 24 hours burned-in, measured, electrically and mechanically tested, matched, properly set up in the amp and finally (and most importantly) tested sonically with regard of the sound required. Also, our extensive knowledge about various tubes' aspects helps us determine which tubes to use in each case.
Additionally, we recommend every player to have a minimum of one spare set of quality power tubes (ideally of the same electrical properties as the ones in the amp to avoid re-bias) and at least one good preamp tube of each type used. Better still, have a full spare set of all tubes for your amp(s), selected so that you don’t need to tinker with the amp to identify the blown tube in the middle of the show. Instead, replace the whole set, and play on as if nothing has happenned.


When a repair has to be done, we always check the whole amp, not just replace one broken part as many possible defects are not evident to an untrained eye. Additionally, over time, we found many parts to break up periodically in the most common types of the amps; even if they seem OK for the time being, they would inevitably break in the near future, so we always recommend to have them replaced too so as to maintain the amp's reliability.
For repairs, we use only quality – sometimes even hard-to-find – components, whose sonic properties will preserve the amp’s original sound best.
We always ask the customer what should be done first to be sure that the work we do will benefit both sides. Needless to say, we always return all original parts, including tubes, to the customer.


People often ask for a modification of their equipment without understanding how much potential there is if the amp were serviced properly. Especially vintage equipment often looses its precious tone due to unprofessional repairs and modifications through the years. So, before any actual tuning or modification, we always have to make the amp sound the way it was designed in the first place. No modification or tuning can help the amp which has bad tubes or broken and/or unreliable components in. Only when this is remedied and the sound of the amp is still far from the player’s expectations, can we make mods.
Many amp vendors change their amps' circuitry over time, not visible to the average user, and usually just one of these versions (if any at all) sounds really good. Also, vendors often introduce different, mostly cheaper, worse sounding components after the initial batch to save cost. On the other hand, even the best parts will not help an amp with inherent design flaws.
Through modification, we can voice virtually any decent amp to the player's specific needs, add a new channel(s) and/or effects loop(s), change dynamics, increase or lower the distortion level and so on. This is the "black magic" of what we do. We also frequently upgrade ESH amps for players looking for the sound and/or features offered by our most recent amps, thus preserving the value of their original investment.
Having said all this, please remember that not all modification requests are reasonable, viable or even doable (we still have to learn how to turn  a low-cost Chinese unit into a well-sounding amp), so be ready to discuss and perhaps reconsider your requirements with us.
We always recommend to fine-tune amps no sooner than after at least one year of heavy usage (the more the better); only after this initial break-in do amps start sounding the way they were designed to.


While the amp is the essential driver of your sound, it has to work well with all other links in the signal chain: – the guitar, enclosure, effect processor, cabling and so on. Should any of these possess or produce improper sonic qualities, the sound of the whole rig will be affected. Sometimes, diverse technical problems or missing features prevent the player from reaching full satisfaction.
After years in the professional guitar gear business, we offer players our extensive knowledge to assist them in their quest for their ultimate sound.

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