As with any German tube, you should expect nothing but the best in sound from these bad boys, and you will not be disappointed. The top five sound qualities shared by German tubes are delivered with perfection by these lovely tubes, and especially on an ultra rare d-getter pair:
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: Siemens & Valvo Hamburg)
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 Tube Testing
This set was tested and certified by RoeTest V11 tester with the following result:
Tube 1:
Measured transconductance (GM): 9.58/9.38 mA/V - 77%/75% (100% = 12.50 mA/V)
Measured plate current (IA): 10.042/10.29 mA - 67%/69% (100% = 15 mA)
Tube 2:
Measured transconductance (GM): 9.71/9.9 mA/V - 78%/79% (100% = 12.50 mA/V)
Measured plate current (IA): 13.155/13.672 mA - 88%/91% (100% = 15 mA)
NO shorts, leakage or gas. NO noise or microphonics.
Curve trace is also included in the original RoeTest report.
Appearance & Cosmetic condition
Despite some loss of paint on one of the tubes, this pair overall is in great cosmetic condition. The 3-line Munich date codes etched on the glass are visible on both tubes although you may need to look closer to see them completely:
