Amplifier match - VTL ST-85

[pranabindu]

Considering purchasing a BeePre.  No experience with electronics, so was going to start with Smash or Quickie, but wife vetoed the apparently incessant battery purchases and wants to hear the mac daddy of the range (I love that woman).

Amp is VTL ST-85 with triode/tetrode switchability:

Vacuum Tube Complement   4 x EL34, 4 x 12AT7
Output power: Tetrode: 60 Watts, Triode: 30 Watts into 5Ω
Class of output operation   AB1
Input sensitivity   0.68V @ 60W
Input impedance   100kΩ
Optimum load range   : 2Ω – 8Ω
S/N ratio   -95dB, 120Hz @ 60W
Power consumption   Idle = 140W, Full power = 500W

Speakers are 93 dB efficient.

Thanks for any guidance you can provide.

[Doc B.]

It will work fine. The sensitivity of the amp is on the high side and the sensitivity of the speakers is slightly on the high side too. This means you might hear some of the microphonic behavior that is present at a very low level in a 300B preamp (or any other DHT preamp). The best approach would probably be to put an inline attenuator in between the BeePre and the VTL, of maybe -6dB to -12dB. This will give you an optimal signal to noise ratio (i.e., drastically reduce any residual microphonics) and allow you to really take advantage of the superior resolution of a DHT preamp. It's a simple and effective approach.

[pranabindu]

Thank you for the response.

Is it correct that the BeeQuiet option would accomplish the same solution to the microphonics issue but in an adjustable manner?

Thank you for your help and your patience with my ignorance.

[Doc B.]

No, the inline attenuator needs to be directly in front of the amp to reduce it's sensitivity.