I'm going to crack open a VK-P5 next week, making sure all its 10 tubes are all ok. I recently bought a step up transformer to try with it.
The story below is my journey on why I went this way.
The VK-P5 sounds good, but I feel it can be better. It has mixed reviews. Some negative, mostly bland. But I know it sounds good. I want it to be great.
Mike Fremers review here was not complimentary -
https://www.analogplanet.com/conten...-preamplifier-produces-luxurious-“velvet-fog”He described it as "Produces A Luxurious, “Velvet Fog”, which I read as a backhanded remark.
He used a .2mV output Transfiguration Proteus with a 1 ohm impedance. To me, that may have been too weak for a preamp 50dB of gain. I believe tubes like to be driven. They dont shine just barely at cruising speed. Carts also shine the best when they are properly loaded. The VK-P5's lower load setting is 100 ohm.
I also found someone who had success with the VK-P5 using a K&K set up transformer.
https://www.audioasylum.com/reviews/Accessory/K-K-Audio/MC-Step-up-transformer-kit/vinyl/391364.htmlHis impression - "the sound is fantastic (necessarily reflecting the contribution of the Dynavector Te Kaitora cartridge, of course). The bass, if anything, is even more extended than with the Clearaudio; and the mid-bass is "richer" and fuller, but no less well-defined. The Clearaudio's strength is in the midrange (try any acoustic piano record!), but this is ever-so slightly more present and palpable. There is a qualitative difference bewteen this and the MM playback, which is that the MM seems to emphasize the leading edge of transients, whereas the MC has more "sustain" in its playback."
I got a Rothwell MC-1 280 ohm set up transformer that produce 22 db gain to attach my Dynavector 20x2L that puts out 0.28mv. I am going to tone down the output of the phono pre from 50 db to 44 db using the internal pot to produce a total of 66db gain with the SUT.
VK-P5 will be set at 47k ohms and 150pf capacitance using a user capacitor slot in the pre. The MC-1 Special will end up giving my Dynavector a 282 ohm load, with a 0.2% db reduction in output. I expect the system to put out a total of 65-66db gain.
I used the math shown here -
http://www.rothwellaudioproducts.co.uk/html/mc_step-up_transformers_explai.html47kohms / 5ohm squared = 1880 ohms
5 ohms / (1880 ohms + 5 ohms) = 0.002db gain reduction
The Dynvector sounds great at 100 ohms. Its sound pretty good at 1000 ohms. I do not expect 280 ohms to be an issue.
Pretty excited to get this system running. 10 tube phono pre with 66db gain. I do not expect to be disappointed.
It'll take a couple weeks giving some free time.
