I had my eyes on Crack for quite some time. I’m going though phases of getting different After exploring various amplification designs—from Push-Pull and SET to Hybrids—I finally turned my attention to the world of OTL (Output Transformer Less) amplifiers. Based on my research, the Bottlehead Crack is widely considered one of the premier representatives of this category, especially at its $279 price point.
The Audio Research VS115 is, by all accounts, a physical powerhouse. Occupying a footprint nearly double that of the iconic McIntosh MC275, this “beast” of a machine makes a bold visual statement. With its wide base and three massive, exposed transformers, the aesthetic is decidedly contemporary and menacing—though those seeking classic elegance may find it a bit industrial.
And here comes another tube amplifier. I was very skeptical when I saw this thing on ebay at first. $86 shipped for a tube am, I thought. It must be a piece of sh**. But I wanted a tube amp for my office at work. It had to be something small. So I started to research about this tube amp and a couple of other amps on ebay. After a bunch of research and being guided by the following thread, I was very close to making my decision.
“Very well made, low noise tubes, the large halo type being acclaimed as sounding near longplate in quality. “ Read
” Amperex 12AU7 (Heerlen factory): excellent tube top to bottom. This one does it all.” Read
“I think the bugleboys are a bit better,but I might be fooling myself, so these comments apply to any Holland made Amperex 12AU7. Full range, nice extension on top with a great sense of vibrancy, transparency and life with very good focus. This tube sounds warm, vibrant, exciting, extended & clean on top, yet smooth and fatigue free all at the same time. “ Read
“…His tonal palette was immediately richer, as if some sonic architect during his construction painted the midbass with broad, bold strokes and then said, “we build here”…” Read
“This is another great tube in the line up. It is smooth, graceful, transparent, and articulate. Its treble is as good as the Mullard 10M but presented in a different style. ” Read
I recently went through testing of a lot of different 12at7. Here is what I found out.
If the tube is used in the circuit it’s designed for, there is very little sonic difference between various tubes in this family. The difference is possibly 1%. I tried NOS Telefunken and ShuGuang with practically the same results. I also tried them in multiple amps with the same results.
