2. amps-preamps
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Extreme Midrange Bloom

Hello: I'm using a BAT VK52SE with the 6H30DR tubes recommended by several folks here on the Gon. I've noticed an extreme emphasis in the upper midrange frequencies which is somewhat unsettling and in fact causes an almost artificial honking presentation. Is this simply the BAT house sound or is there something I can do to resolve this anomaly? I've never experienced this in any other preamp I've owned in the past. I love the build and general fit and finish of this preamp. The user interface is excellent. An audio enthusiast friend suggested this could possibly be a result of the oil filled caps BAT is using. Any help would be most welcome since the pre is great in every other way. Accurate bass, sweet highs and a very unfortunate bloated midrange.
frontier1
jaybo
4,478 posts
 
could be a loudspeaker issue
guidocorona
4,298 posts
 
It is worth pointing out that Frontier1 is baselining against the excellent ASL Flora, which is not displaying the excessive bloom. This suggests that the issue may be specific to the VK52Se. Frontier1 already reported this bloom to me before replacing the SovTec 6H30PIds with the DR NOS Supertube variant.
rodman99999
5,988 posts
 
How many hours do have on this unit? Most take 200 before sounding their best. Some interconnects can interact and cause anomalies as well. If this is a new unit- give it some time. You can burn it in by playing your CD (on repeat) through it with your power amp turned off. What did it sound like with the original tubes?
frontier1 OP
42 posts
 
'Thank you gentleman, your observations are quite astute. One radical suggestion has been to change the output coupling caps to teflon since oil caps can possess a certain forward sounding midrange. This, of course alters the intended sonic signature of the preamp. I'll continue to burn in the beast and see what gives. As stated in my post, this preamplifier has more air and top extension than several others I've had the opportunity to preview.
guidocorona
4,298 posts
 
It seems BAT consider its pervasive use of oil capacitors a main feature of the VK 52SE. Design of 52SE may very well have been optimized for these caps. See:
http://www.balanced.com/products/line/vk-52se/index.html
I fear that replacing those oil caps with other technologies may yield unpredictable results. . . how about talking to BAT first about your concerns?
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