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Yes. I stumbled over this ad too - pretty rare to see a full double rotary Eb/Bb tuba ... but the price is prohibitive for me ..

The price is on the insane side of outlandish, with a hint of crazy.

How is this different than any other E flat tuba with a 4th valve ? It doesn't look to have any enormous amount of tubing.

I assume BB side adds extra tuning length, essentially compensating for the rest of the horn

Eflatdoubler wrote:How is this different than any other E flat tuba with a 4th valve ?

Could be - the difference, am I right? would be that the extra valve tubing would be deployed in combination with the normal valve tubing, so it's short. Where in a full double, I'm imagining that means simply an alternate valve, so the extra valve tubing is the full length of that valve in the corresponding key. The pictured tubing, on the underside, looks short to me.

Whether it's slow or has tuning problems, I'd have no idea. I guess if I were feeling a great need for something like this, I'd be making travel plans to Boulder to find out.

Very interesting horn. I don't know enough about tubas (and especially this one) to tell if it is a 3+1 comp or true double.

However, the dual connecting tubes between the valves are not something I have seen on a 3+1. My guess is it's a double tuba.

If this is a one-of-a-kind, the intonation may indeed be wonky. But within the limitation that there are only 3 working keys for each side of the instrument, a properly made double should theoretically have pretty good intonation . . . nothing like holding down the 4th valve to play in Bb.

Hup

I spent some time checking out all the tubing. This is what I gather:

If the "change valve" (left hand) is not depressed, the horn acts as a regular Eb with 3 valves. Leadpipe enters the valve block, using the upper tubing (visible from the front of the horn, away from the player), then exits and goes on to the bugle as usual.

If the "change valve" is engaged, then the path is routed through a loop which then first enters through the lower tubing (closer to the player) of the valve block. It then exits, loops all the way back to the top and then reenters the valve block but this time flowing through the upper tubing.

This means that the horn is not a true double, as in a double french horn. When the change valve is engaged, it just adds the amount of tubing needed to the Eb circuit to get it to the length needed for Bb. So, it's more like a compensator in that regard. One interesting difference is that in this set up, the path flows through the "compensating circuit" before entering the "open circuit". Not that it should really make a difference. After all, trumpets flow through their valve blocks backwards and it doesn't seem to mess them up... too much. : )

I dig tubas and all but I was really hoping for beer maiden pics...

It works like a double French horn. The fourth valve is not a "compensating" valve in any sense of the word. It is a "change valve."

I inquired at Hirsbrunner. Here is the response:

Thank you for your request. The instrument on Ebay is a Eb-Tuba HBS 188. The
tuba has the compensating system. The compensating works with the use of the
4th valve. The 4th valve is a 2 and 1/2 tone step and lowers the instrument to
Bb-flat. So you have the possibility to play in the Bb range while pressing the
4th valve all the time.
The instrument which is offered on ebay was made in the 1990ies.

Sincerely yours
HIRSBRUNNER & CO AG

Peter C. Hirsbrunner