Vintage Amps 101

Amps are cool too……..

Welcome to my world. Guitar amps have been part of my life for over 40 years. For most of my career I helped guide the direction of two legendary brands, VOX and Marshall. For the last four years I’ve been modding, restoring and building quality amps right here in the USA.

This new column in GA will focus on the essence of vintage amps. Below I show you things to look for that affect value and tone when buying vintage. In future columns, we’ll get into specific brands and models.

Vintage amps are like vintage cars. Old cars don’t have slick modern features like GPS or heated seats, but they have what it takes to make for a fun riding experience (plus you know you they make you look cool!). We like vintage amps because of superior sound, collectability and attractive design. Just like a vintage car, you have to expect that a vintage amp will need a good going over or a complete overhaul depending on where it’s been, how much it’s been played and how it’s been maintained. When buying a used car, it’s prudent to have your mechanic check it first. It’s the same for amps. Find a good tech, have him check it before purchasing and have him do the necessary work. If you don’t know a good tech, ask your friends or other amp enthusiasts on the web.

What to look for depends on whether you are buying for collecting or playing. Will you play at home or with a band? Will you play small clubs or stadiums? Here are things to look for that affect the value and playability of a vintage amp:

As with any antique or collectible physical condition counts. Visible and irreversible cosmetic modifications on amps are as much of an issue as on guitars. It’s not unusual to find mini switches or pickup routs on guitars. On amps you may find fans cut into cabinets or extra holes in front and back panels. These severely reduce collectability and value. If you are collecting look for original logo, covering (tweed, vinyl, tolex, etc) and grill cloth. Corners, piping, handles and feet matter but are less important. If you are looking for tone cosmetics don’t matter except grill cloth which can affect the sound.

The original speaker is a big factor to both value and tone. For collecting, the original cone can be an issue for a “museum piece”. However, old speakers will eventually fail. If you plan on using the amp, especially at loud volume, you’ll have to get it reconed sooner or later. The parts are available and there are a lot of techs who can make these old speakers come back to life.

Transformers are very important to value and tone. Thankfully there are good replacements from a variety of sources. The most important is the output transformer, then the power transformer then the choke. A replaced power or output transformer could devalue the amp by as much as 15 or 20%. More if both are replaced.

The capacitors in the signal path make a difference to the tone and value of the amp. Collectors and players both look for original caps. The problem is a lot of the old amps used parts that have failed or will fail. There are good replacements.
Filter caps will fail because they have a shelf life. I’ve seen 50 year old amps with original filter caps that work fine but they will fail eventually. They affect value somewhat but while original filter caps are fine for a museum piece, get them replaced if you plan on using the amp.

Resistors can and do fail. Many older amps used carbon composition resistors. These have a reputation for good tone but drift in value over time and get noisy. How much and how bad depends on the quality of the originals.
I recommend that when changing parts the replacement be of the same composition as the original in order to keep the tone as close as possible. There are sonic differences between resistors and capacitors of different construction. Some NOS parts are available but hard to come by and expensive. Avoid old filter caps whether new or used.

Most people who collect old amps understand that parts will need to be changed. Sometimes a tech will use the outer part of the failed part and insert a new part inside so it looks original. Some people hang on to the original parts so that when they sell it, the next person can have them as a memento….