Product Summary
The top five sound qualities shared by German tubes are delivered with perfection by this lovely Valvo Hamburg tube, with further enhancements thanks to the ultra rare 45° foil D getter:
1) Holographic sound stage (leading brand: Telefunken)
2) Non-fatiguing top end extension (leading brand: Siemens)
3) Natural tone/flat midrange (leading brand: Valvo Hamburg)
4) Deeply controlled bass (leading brands: Valvo Hamburg & Siemens)
5) Ultra clarity and layered details (leading brand: Telefunken)
Sound Characteristics
Over the years, we have found the bass on Valvo Hamburg even more appealing than on Siemens (allegedly the King of Bass and that's fine) for a very important reason: there's added substance and weight to the lower midrange that makes the bass more pronounced without being overpowering. This special sound characteristic can only be found on Valvo Hamburg tubes. And because of the added substance in sound, the overall tonality of these tubes feels sweet, warm and musical, and the ambient clues sound closer to your ears. One may find Telefunken's midrange thinner compared to Valvo Hamburg as a trade-off of a more enveloping and curvier holographical sound stage...the law of physics applies here as well - the shape of sound can only change in one direction.
Professional Sound Evaluation
The pair worked wonderfully and sounded terrific in our professional studio setup for monitoring.
- Input: Cambridge Audio CXC V2 dedicated CD transport + Schiit Audio Bifrost 2 Multibit DAC
- Amplification: Woo Audio WA7 Fireflies (3rd gen) Balanced Headphone Amplifier
- Output: Focal Clear MG Pro open-back headphones
Our full tube sound review was written 100% based on the actual listening experience while this pair of tubes were running in the system described above.
Professional testing & sound evaluation
This set was tested and certified by RoeTest V11 tester with the following result:
Tube 1:
Measured transconductance (GM): 2.44/2.53 mA/V - 111%/115% (100% = 2.20 mA/V)
Measured plate current (IA): 11.68/12.482 mA - 111%/119% (100% = 10.50 mA)
Tube 2:
Measured transconductance (GM): 2.47/2.46 mA/V - 112%/112% (100% = 2.20 mA/V)
Measured plate current (IA): 12.122/12.49 mA - 115%/119% (100% = 10.50 mA)
NO shorts, leakage or gas. NO noise or microphonics.
Curve trace is also included in the original RoeTest report.
Appearance & cosmetic condition
Besides the world-class sound characteristics, we treasure this pair also because the excellent condition of inscriptions on the tubes given its age. The identical 3-letter (Pre-1961 Hamburg date code is 100% visible on both tubes:
K62 D6J (k62 = ECC82 Production gen #2, D = Hamburg, Germany, 6 = 1956, J = October)
K62 D6K (k62 = ECC82 Production gen #2, D = Hamburg, Germany, 6 = 1956, K = November)
Packaging
New reproduction Valvo tube boxes.
