OB woofer (FAST) for tube amps

[MJK]

I would not have done it that way. But that is just me I guess.

[Bob Brines]

OK, what I am suggesting is that while anything is possible, why do things the hard way. SS is great for bass, tubes are great for the top end. It makes life much more simple to do it that way. There is really nothing to gain by using tube for bass other than proving that it can be done.

Bob

[dhieber]

I agree that using an active crossover with a solid state woofer amp on the low pass side has many attractions and I certainly would go that route for a subwoofer.

As a first OB speaker project I was considering something similar to MJK’s passive two-way speaker, but driven by tube amps because those are what I build and enjoy and they are the best amps in my house (IMHO). My thinking was that the Beta 15 would be significantly underdamped with a no feedback tube amp and might work as well as the Alpha 15 with a feedback (high damping factor) amp. I understand how to calculate the effect of added series resistance on Qts, but in the absence of simulation tools such as MJK’s worksheets I was seeking guidance from actual experience. It seems Nelson is the only poster who has actually tried this driver in OB. For simulation, I suppose I can use Edge together with the driver’s infinite baffle response (adjusted for series resistance) to approximate the OB response.

If I were to actively crossover, I would prefer not to mix solid state and tube power amps for crossovers in the midrange (300 – 400 Hz). Of course, I might like it if I tried it, and I do have some unbuilt gainclone kits sitting on my shelf.

BTW, I attended VSAC 2008 and I thought the sound in the Lowther of America room was quite good.

[planet10]

Originally posted by Bob Brines
SS is great for bass, tubes are great for the top end.

This is a generalization... the best amp we have in the bass has tubes. It is limited to 3.2 W thou, so it is only best with efficient speakers. For the innefficient ones i bi-amp with a 150w dual mono Mosfet amp.

That tube amps can't do bass is largely a consequence of SE amps (SS ones have trouble with bass too) and a predominance of PP amps that hark back to vintage amps.

dave

[seanzozo]

Originally posted by dhieber
I agree that using an active crossover with a solid state woofer amp on the low pass side has many attractions and I certainly would go that route for a subwoofer.

As a first OB speaker project I was considering something similar to MJK’s passive two-way speaker, but driven by tube amps because those are what I build and enjoy and they are the best amps in my house (IMHO). My thinking was that the Beta 15 would be significantly underdamped with a no feedback tube amp and might work as well as the Alpha 15 with a feedback (high damping factor) amp. I understand how to calculate the effect of added series resistance on Qts, but in the absence of simulation tools such as MJK’s worksheets I was seeking guidance from actual experience. It seems Nelson is the only poster who has actually tried this driver in OB. For simulation, I suppose I can use Edge together with the driver’s infinite baffle response (adjusted for series resistance) to approximate the OB response.

If I were to actively crossover, I would prefer not to mix solid state and tube power amps for crossovers in the midrange (300 – 400 Hz). Of course, I might like it if I tried it, and I do have some unbuilt gainclone kits sitting on my shelf.

BTW, I attended VSAC 2008 and I thought the sound in the Lowther of America room was quite good.

You might try basta. It can simulate both the baffle effects for an OB and can add series resistance.