08-05-2009, 10:06 PM
TEX: indeed, the Heath W5M amplifier was one of the best ones that Heath ever produced, but unfortunately, it was a Williamson. In around 1957, I bouight a new E-V Regency III speaker system, a Fisher 800 tiner, and a Heath W5M amplifier kit. Nothing could have sounded better, so I felt. After a short while, I noticed that the E-V speaker system had no highs. The tweeter was dead, so opened up the cabinet, and the tweeter was open. Back to E-V, across the state, and they replaced the cone for gratis, explaining that some amplifiers will blow tweeters. Indeed, ANY Williamson will.
Williamsons sound beautiful.I had another in the sound bay in my shop. I was working on an AM broadcast set on the bench, with a record playing thru the W'son into an ordinary speaker. Amazing, I tuned in to a station that was playing the identical record I was!! Such a cooincidence. I lifted the pickup from the record, and the station stopped playing the tune, as I did. The Williamson was a fine AM band transmitter. Didn't check, but it also must have gone up into the SW bands too. Little wonder that the Williamsons popped tewwters as quickly as you could replace them. They also oscillate at sub-sonics. I've seen a speaker with a Williamson driving it.As the music played, the cone oscillated in possibly 2 cycle high amplitude excursions.
I understand that there is some phase shift, occurring in the output transformer, and the inverse feedback loop becomes positive feedback at both high and sub-sonic frequencies. I dumped all of the Williamsons I had, and went to more conventional amplifiers. Haven't lost a tweeter since.
Williamsons are inexpensive. Tweeters aren't.
Williamsons sound beautiful.I had another in the sound bay in my shop. I was working on an AM broadcast set on the bench, with a record playing thru the W'son into an ordinary speaker. Amazing, I tuned in to a station that was playing the identical record I was!! Such a cooincidence. I lifted the pickup from the record, and the station stopped playing the tune, as I did. The Williamson was a fine AM band transmitter. Didn't check, but it also must have gone up into the SW bands too. Little wonder that the Williamsons popped tewwters as quickly as you could replace them. They also oscillate at sub-sonics. I've seen a speaker with a Williamson driving it.As the music played, the cone oscillated in possibly 2 cycle high amplitude excursions.
I understand that there is some phase shift, occurring in the output transformer, and the inverse feedback loop becomes positive feedback at both high and sub-sonic frequencies. I dumped all of the Williamsons I had, and went to more conventional amplifiers. Haven't lost a tweeter since.
Williamsons are inexpensive. Tweeters aren't.
