Biamp TK2050 with tube amp - any benefit ?

[hillbear]

I have a Audio Innovations First 2A3 tube amp. Slightly faulty at the moment and will require service. I use this with Border Patrol PSU. I got a TK2050 from Hifimediy recently to keep me going until I got the First going again. Wow! This thing is superb - I use SLA batteries and quality stepped attenuator. Question is - do I stick with TK , get First sorted and then run in biamp mode ?? Say, the TK on bass , with tubes on midrange/high ?? Is it worth the hassle and expense. Shall I get another TK for £25 and run biamp with that?? Any thoughts welcome !

[whaleman]

I wonder if you would run into some timing issues with the TK being quite fast and the tubes not...just a thought.

BTW, I am wondering if it is worth it to spend $40-50 for a quality stepped attenuator or an AlPS is sufficient. Do you notice a significant improvement with the stepped attenuator?

[SY]

Originally Posted by whaleman

I wonder if you would run into some timing issues with the TK being quite fast and the tubes not...just a thought.

Transit times in amps are on the order of nanoseconds. And given the lowpass filter needed at the D amp's output, the bandwidths and risetimes won't be all that different anyway.

Using a separate solid state amp on the bass is one of the greatest improvements one can make to a tube power amp.

[suntechnik]

I never understand benefits of mixing tubes and SS. imho in that case not pro but contra of both wolds are emphasized.

Tube amps (PP UL) have excellent bass btw, better then most SS.

[SY]

If by "better" bass, you mean "higher LF cutoff, higher LF source impedance, and higher LF distortion," then yes, tube amps have better bass. And with increased intermod, that "better bass" helps to increase midrange distortion as well. Even better, the requirements for an output transformer to handle deep bass at power mean a larger core, so increased leakage inductance and much poorer HF performance. w00t!

[whaleman]

Originally Posted by SY

Transit times in amps are on the order of nanoseconds. And given the lowpass filter needed at the D amp's output, the bandwidths and risetimes won't be all that different anyway.

Using a separate solid state amp on the bass is one of the greatest improvements one can make to a tube power amp.

Exactly, nanoseconds can introduce spatial effects. However, these can be pleasant in some circumstances, but you get away from accurate. I would try it though, this is just a consideration.

[hillbear]

Thanks for your thoughts - I have tried various combinations of TK pot, sepearte pre-amp, stepped attenuators..etc. The best to my ears is to remove the TK pot and solder in a stepped attenuator (£20 from VALAB or the like from ebay). I think its worth the extra cost/effort.

[SY]

Originally Posted by whaleman

Exactly, nanoseconds can introduce spatial effects.

A few million of them, perhaps. Otherwise, I'm sorry, that's nonsense.

[wwenze]

Speed of sound wave in air: 343.2m/s
Time taken for sound to travel 1cm: 29µs

[SY]

Originally Posted by wwenze

Speed of sound wave in air: 343.2m/s
Time taken for sound to travel 1cm: 29µs

Right, exactly. Now, what's the woofer displacement during the music- 1cm or so? That represents 29,000 ns right there.

At transit times of 10ns, this represents a speaker displacement of 0.003mm! I suspect that this isn't going to upset timing cues.