During the time when Andy at Vintage Tube Services had no 5AR4s,
I also talked with Brendan Blever at Tube World.
I told him I was running Bendix 6900s in my Modwright linestage
and had recently gotten the tube-rectified power supply upgrade
which came with a stock Sovtek 5AR4.
I had seen that Brendan had run Bendix 6900s (in place of 5687s)
in his Emotive Audio Sira preamp and he had thought they upped
the perfomance substantially.
We discussed all his 5AR4 offerings and then I asked him what 5AR4
would best complement the resolution and dimensionality of the Bendix 6900s.
He recommended the Philips Miniwatt metal base GZ34 NOS 1957.
I went for the cryoed version and received it maybe 10 days ago
and it has replaced the Sovtek in my Modwright ever since.
The Philips metal base GZ34 is a beautiful tube.
It brings more clean, taut bass content,
some midrange bloom but not bloat,
and adds a touch of sweetness and relaxation
to the high frequency energy of the 6900s.
What it brings to the music in terms of resolution
and smoothness goes way beyond the Sovtek to my ears.
rlmacklin
