We now offer Factory matched pairs - these tubes are only tested and matched by factory. Ship from China directly. Defective products return into Canada, not China.
The sale price on this listing is for factory matched pairs. We do not guarantee accuracy of the test results. If you are looking for the perfectly matched high quality tubes, please look into our Grade A listing.
Special note: Although this tube is modeled as CV181 by the Chinese manufacturer - Shuguang, please do refer to the tube data at bottom of this page to check compability with 6SN7 / 6N8P tubes. The treasure CV181-Z has heater current of 0.6A, not 0.9A as typical CV181 tube does. A comparable RCA 6SN7-GTA tube date has been added at the bottom of page for your convenience to compare.
" It succeeds in beating the best NOS samples at their own games with the added bonus of new stock reliability and dependability".... "I have spent many long hours burning-in and auditioning NOS 6SN7 (there's so many to choose from) and the Shuguang CV181Z beats them all with maybe 50 hours on them and they claim to need 300 hours"
Mark Wheeler - TNT-Audio
Read the full review here: http://www.tnt-audio.com/accessories/shuguang_treasures_cv181_e.html
True "Treasure" as a result of Shuguang's 50-years' of expertise in vacuum tube design and production.
- High Polymer Compound Carbon (HPCC) coating is for the first time used on vacuum tube production. Compared to traditional carbon spray technology, HPCC coating will allow greater concentration of electrons, enhance and maintain stability of the electron flow, maximize "secondary electron emission surpression" from the glass enclosure, in turn reduce effects of electron swirl which generates internal noises from the vacuum tube itself.
- 'Super Alloy' technology is for the first time used in constructing vacuum tube. 'Super Alloy' technology was invented and first used in aviation, aerospace, military and other high-tech area. After 3 years of testing under extreme conditions, Shuguang has successfully adopt such technology in vacuum tube constructing to achieve directional solidification and single crystallization, greatly improving the ability of electron emission and electron current stability.
- Improved vacuuming technology during production process to clear signal background - Key assembling process is manually completed by a small number of senior technicians with 30+ years of experience.
- 60 extra parts selection and matching processes are adopted to ensure premium quality tubes, compared to the Shuguang generic clear glass tubes.
- Premium Grade matched right out of factory to serve outside of China market
- Interchangable with 2A3 family of tubes
- Suggested burn-in time 150-300 hours. Most changes happen in the first 150 hours.
A bit about Shuguang:
Shuguang is the oldest and largest tube manufacturer in China, established in 1958 by engineers educated and trained in the United States in the 30-40s. Shuguang's vacuum tube production accounts for the world's 40% total tube output nowadays, either under their own brand "Shuguang" or under OEM brands. Generic Shuguang tubes come in clear glass enclosure. The Treasure series are only released in Dec 2008 to celebrate Shuguang's 50th anniversary and technology advancement. Grant Fidelity is the very first international distributor of Shuguang Treasure series outside of China. All Shuguang tubes distributed by Grant Fidelity comes with standard 30 days warranty plus a 12-month optional extended warranty.
Premium vs. Standard; Grade A vs. Grade B
All Treasure tubes from Grant Fidelity is of Premium Grade export quality from Shuguang and they are superior to those sold out of China or Hong Kong - which are intended for Chinese market and are commonly referred as Standard Grade. Standard Grade treasure tubes have much wider variance in specifications and could deviate from the tube's designed specs by up to 40%. If you are looking for first class quality tubes and want protect your investment, we strongly recommend you to buy 'Premium Grade' only. The Treasure Premium Grade tubes imported by Grant Fidelity are further divided to Premium Grade A (perfect matching on every aspect and strong emission) and Premium Grade B (less than perfect matching in certain aspects such as plate current, transconductance or minor internal gas, slightly less emission. However we guarantee that none of these minor weakness will interfere with the tube's normal operation and pose no safety hazards to your amp. Grade A tubes are sold with a price premium over that for Grade B. Even if you purchase 'Premium Grade B' tubes from Grant Fidelity, you are getting better tubes than the Chinese 'Standard Grade' sold over eBay type of places. Buyer beware.
Please note that Grade B tubes are guaranteed no DOA (dead on arrival) and carry the same warranty as Grade A. However, we do not warranty cosmetic appearance on Grade B tubes - they are categorized as B-stock with certain imperfections.
Important Readings! About Chinese vacuum tube production and distribution:
|shuguang treasure tube spec cv-181.pdf||142.45 KB|
|RCA-6sn7 spec.gif||40.24 KB|