zebrano wood beepre

[marco08]

redid the base, leaving a bit of air on the sides for cooling, and resting the baseplate on silicone mats.

love the look and the sound.

 

[Karl5150]

...and more room for big caps? Nice work.

 

[johnsonad]

Impressive!

Are those ball bearing as weights on the 300B's?

 

[marco08]

yes, ball bearings give it a nice steampunk look, and they match with the titanium coating on the 300bs..

I would have loved the vinyl covered lead rings, but can't get them in france for a reasonnable price.

takes care of the microphonics, anyways

 

[johnsonad]

Weight is all that's needed and those look better than the orange rings. I'll try them in the future!

 

[Doc B]

That's not quite accurate. Mass is part of the recipe for sure. What we are trying to do is transfer vibrational energy from the tube to the weight. However if we just consider mass with no damping - in other words we just use a high density, hard mass - the energy just keeps bouncing around. In fact if you keep increasing the mass at some point it becomes a pretty efficient reflector of the energy coming from the tube.

If you add a soft, squishy component to this mix the energy can be dissipated into that squishy stuff. Thought the actual intent of the vinyl on the lead rings is simply to contain the lead inside and protect the glass flask it is designed to rest upon, it happens that it's also quite a lossy material. We know the flask weights are kind of hard to acquire, and as an alternative PJ cooked up a weight that was composed of a few big steel washers of a total mass similar to the lead, with some silicone o-rings in between them for damping. Though it seemed like it should work very well, the lead and vinyl turned out to work much better.

 

[johnsonad]

Interesting, thanks Dan.

 

[tsingle999]

Beautiful Beepre!
I just scored some Mapleshade brass tube halo's on ebay to try vs the lead rings. They have 3 screws that attach to the tube so the brass ring isn't touching the glass envelope itself. Will let you know how it works. Taran

 

[JamieMcC]

Love the Zebrano enclosure and those bearings look a perfect fit.

 

[marco08]

doc is right, as usual.

i got a piece of silicone sushi mat between the bearings and the glass !
provides the dissipation and gives homage to the japanese heroes of the early Marantz era !

 

[johnsonad]

doc is right, as usual.

i got a piece of silicone sushi mat between the bearings and the glass !
provides the dissipation and gives homage to the japanese heroes of the early Marantz era !

That made me laugh!  They still look better than the orange rings!

 

[Doc B]

Early heros of the Marantz era were Saul Marantz, Sidney Smith and Dick Sequerra. It didn't go Japanese until 1966, after the company got in financial trouble with the 10B tuner and Saul sold it to the owner of Superscope.

 

[tsingle999]

I played around with the red lead rings and the mapleshade brass rings. I liked the double red rings on each tube the best but the differences were pretty subtle. The Mapleshade rings didnt fit the tj 300b tubes properly though.

 

[marco08]

thanks doc for the reminder !!