There seems to be two schools of thought on replacing parts on vintage amplifiers. One is to leave the amp all 100% stock original. The other is to replace what is needed to make the amp more reliable and sound it’s best even if the original parts are still working. I am actually dealing with this situation right now with the above 1966 Fender Deluxe Reverb amp. The electronics are all 100% original but it does not sound very good. Also the cosmetic condition is about a 6-7 out of 10 which probably not appeal to a collector. In the end it is up to the owner to decide which way to go. Let’s look at both views.
Keeping your vintage amp 100% all original is certainly good for collector and resale value. The collectors I’ve dealt with in the past like to find amp as close to 100% original as possible and in good cosmetic condition. If you have an amp that is 100% original and looking good it may be best to leave it this way for the obvious reasons. This is the type of amp that gets played at home on occasion. As a side note it is actually good to play the amp every so often to preserve the electronic components.
On the other hand by replacing key components such as electrolytic filter capacitors the sound and feel improves while reliability increases. As time goes by the amp ages and the oily paste inside the electrolytic capacitors dries out. This leaves you with a capacitor that is not performing to 100% of it’s potential. The sound and feel of the amp suffers. The tone can be muddy and blurred particularly with lower bass notes. The amp can feel sort of dead and sluggish like you have to work harder to get your notes to sing. Another important factor is the reliability. I have been seeing more shorted electrolytic filter capacitors lately. By replacing these capacitors with new ones you will restore good tone and feel as well as dramatically increasing the reliability of your amp. I always save any original components that have been replaced with new ones for the owner. I doubt they will ever be used again but sometimes this helps with resale value.
Another component that I highly recommend replacing on a vintage amp is the old style 2-prong AC cord. The modern 3-prong AC cords have a third conductor for grounding. The old style 2-prong cords rely on a capacitor tied to a switch that is connected to each of the two conductors with one of the switch terminals connectedd to the chassis ground. If this capacitor shorts the chassis can become “hot”, meaning that one of the AC legs will be connected to the chassis through the shorted capacitor. This capacitor is nicknamed the “death cap” for obvious reasons.
Speakers are another component that should probably be replaced if the amp will be used for frequent gigs and sessions. There are many excellent choices for replacement speakers. Eminence alone has over eighteen 12″ models to choose from in just their Patriot line. I recommend to vintage amp owners that use their amp for steady gigs and sessions to remove the original speakers, put them in a box and replace them so the originals do not get blown. A speaker with an original working cone is obviously worth more than one that is blown or re-coned.
So in the end you have basically two choices on whether to replace parts on a vintage amp. 1- If you are a collector and do not plan on playing your vintage amp very often it’s probably a good idea to leave the amp 100% original. This will preserve the value of the amp for a possible future sale. 2- If you plan on playing your amp for gigs and sessions it is best to have the amp serviced and have the electrolytic capacitors replaced along with any other components such as the 2-prong AC cord and speakers to ensure reliability and good tone. I always like to leave a vintage amp as close to original as possible but each amp and player has different needs for their situation. It’s probably best to assess your playing situation and make your decision based on whether you are more of a collector or player.