FUQ (eff -yu - cue) - FAQ's with an EDGE

Tagged As: Used Guitar Amplifiers

Question:
Maybe a weird question? Who would want to overdrive a Hifi amp? For listening to music, I wouldn't For making music, maybe I would... But I wonder how it would sound to overdrive a tube Hifi amp? How does it respond? I've never tried, so I have no idea. I'm interested about it as power amp overdrive is commonly used with guitar amps. I need a Hifi tube amp for my specially designed guitar setup, and so I thought if I could mod my Hifi amp to be able to overdrive it. No I'm not going to blow my amp. Instead I would like to use a power scale with the amp. If I remember correctly, it's just a way to adjust the B+ supply voltage lower with a circuit that has a pot as the adjusting component. In guitar amps it's used to lower the wattage of the amp. So, you can lower a 50W amp into a 0.5W amp and run it at max setting, thus distorting the amp without too much volume, and damage to the amp. It also has an adjusting fixed bias circuit that adjusts according to the B+ voltage, keeping the bias at usable level. But guitar amps aren's Hifi amps nor the other way around. If you have a 50W Hifi amp, that runs as a 0.5W amp, and put the volume dial at 10/10, does the sound even distort? And if it does, what kind of distortion is it? I guess it depends on the amp. I know that's a good way to blow the speakers so that needs to be taken into account with special speaker setup. I'm just thinking if I should try it or trash it as an useless idea. If the overdrive or clipping sounds awfull it's useless. I'm talking about how a guitar signal would sound when fed through an overdriven Hifi amp. Any ideas?

Answer:
In my studio, in the main studio there are two amplifiers, a Hafler P4000 and an Eico HF89. The Hafler is a modern mosfet design, viewed as somewhat of an audiophile amp designed for flat response in recording studios. For demonstration purposes I built a switching device that can instantly switch between the two amps. I have given this test to numerous musicians and lay people. Of all tested, I have found only one individual that could reliably tell which amp was playing. He is a long-time audiophile who has listened to and owned some of the most expensive solid state amplifiers ever made. He thought the Eico had a better soundstage than most of the amps he had listened to. Not having heard a tube amp in some time, he was somewhat shocked at how much he liked it. In the control room we use an old Acrosound Ultralinear ll, one of the great tube amps. My mixes translate very, very well to other systems. Remembef that initially (in the 30's) there was no such thing as a guitar amp. There were only amplifiers. They were used primarily for audio reproductiom, but one day someone wound a coil, put it on a guitar, and pluggee it in. Voila! The ruddu thing worked! From then on, the actual guitar amp was developed to maximize its potentials. Overdrive and distortion were discovered as different possihle sounds -- and musicians are known to use any sound at their disposal. To directly answer your question, if you overdrive a hi-fi amp, you'll get crappy sound.