Vintage Tube Gear Priced Insane Now


Few stereo tube gear are under $1K on eBay. If so are only 12 to 15 watts per channel. The vintage gear needs a complete rebuild on top of the horrid price. Most new tube amps do not have a phono stage either.

jimbennet

As the owner of some very coveted vintage gear, I should be happy that most of my gear has substantially increased in value since I purchased it.  Still, it is abit sad that others might be squeezed out from owning stuff that remains terrific sounding after all these years.

With tube gear, there is nothing we know today that was not known 70 years ago.  It comes down to quality of the parts and the skill of the builder in voicing the component.  Foremost in importance is the output transformer, followed by the coupling cap and then all the rest of the components.  Depending on the kind of sound one seeks, it may not be the case that modern components are better.  Whether it is the case of cost cutting or a lost art, many of the best sounding transformers are vintage.  Likewise, many prefer the sound of older caps even though they don’t measure as well (not as tight tolerances, higher ESR, slower slew rates, etc.).  Even resistors matter and I know builders who prefer old carbon composition resistors over the latest offerings with ultra tight tolerances.

IMHO, making vintage gear reliable involves a lot more than coupling caps and tubes.

Much vintage tube gear contains carbon comp resistors which are hygroscopically reactive, and when they go out of spec, rather counterintuitively, they increase in resistance. So all carbon comp resistors should be checked. Sometimes, they can be oven baked to get them back in range.

The next problem is usually line voltage, which at my place runs around 122V. Most vintage gear is designed to run at 115-117V, so this should be addressed if ones line voltage is high. A bucking transformer, variac, or even a couple of thermistors in series should knock down the voltage.

And if the vintage tube gear is stereo, a fair amount of it will have PECs in it. They can last forever, or they can go tomorrow. I replace most of them with discrete circuits, YMMV.

And common selenium, or "top hat" diodes, suck and release toxic gas if they give up the ghost, so they should be replaced with modern diodes. The problem here is that modern diodes are more efficient and the downstream voltage will rise, necessitating a dropping resistor.

And back in the day, tubes were cheap, so much vintage gear runs the output tubes hard. A problem that is exacerbated by higher line voltages. Especially if using new production output tubes, bias voltage will need to be adjusted, some vintage gear does not allow bias adjustment, so a work around needs to be installed.

The Savvy EE, buying into a Vintage Rebuilds, has pretty much shown the BOM for parts, the time requirements to refurb/rebuild are both non-concerns.

The challenge fulfills an area of interest that runs parallel with being interested in audio in general.

I'm sure my own interest in Bearing Housings undergoing design changes on Vintage Era TT's has very little to do with my Interest in audio, even though my interest in audio took me to this area of investigation.

I would say it is my interest in understanding mechanics and attaining improved efficiencies for mechanical functions is the interest that is deeply rooted in the Bearing Housing Interest. The interest in audio that runs parallel, then has something extra attached that is proven beneficial to the experiencing End Sound produced from an audio system.