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Amperex PQ 7308 (Enhanced 6922) Matched Pair - White Print - USA 1960s - NOS

Amperex PQ 7308 (Enhanced 6922) Matched Pair - White Print - USA 1960s - NOS

Regular price $475.00 USD
Regular price Sale price $475.00 USD
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Product Summary

Our best seller is back in stock - the Amperex USA PQ White Label! This listing is for a tightly matched pair with identical date code from 1963,  one of the best years of Amperex USA and and very rare to find today. We have recommended PQ's to more than 20 wonderful patrons of the Soundlumia eBay store, who are enjoying these tubes in their class leading amplifiers from Audio Research, Ear, Schiit Audio and Cavalli etc. and are raving about the superb PQ sound around the world. 

Sound Qualities

Among all the PQ tubes, the USA white print version (made in Hicksville, New York) is the most sought-after by serious audiophiles and tube enthusiasts. They are as sweet and smooth as the Amperex Holland PQ tubes, with even better detail and very spacious sound stage, which offers an amazing bird's eye view of the shape of your sound, so you know exactly how tall and wide the sound stage is. The tone is warm yet lively, mids are forward but also expansive like what you hear on their cousins from the Holland factory, bass is punchy but not heavy. We have recommended them to so many satisfied customers that we have given them a nick name "sound purifier" - the sound that comes from these tubes has absolutely no edginess, glassiness or harshness, and you hear nothing but the soul of your music and all of it. They are the best tubes to to put in the phono stage to "purify" your sound in my opinion. As to vocals, I have no further comment than that the best Mullards were actually sourced from Holland PQ's (Made in Gt. Britain w/ Heerlen date codes) and USA PQ's beat the Holland ones in vocals period. Listening to Righteous Brothers' Unchained Melody through these PQ tubes should be on your bucket list, no matter what type of music you enjoy.

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: Liquid Platinum Tube Amplifier by Alex Cavalli 
 - 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 Tube Testing

Both tubes tested Super Strong NOS (120%+ mutual conductance) and tightly matched on a reliable and recently calibrated Mercury 2000 tube tester with the following result (mutual conductance both in uMhos and in percentage of nominal):

Tube 1: 16,800/17,000(132%/133%) 
Tube 2: 16,500/16,000(131%/128%)

Good tubes start at 7000 and new tubes (incl. NOS/NIB) 12,500 - 13,000, and the Mercury 2000's rated mutual conductance (nominal) for new tubes is 12,500. Test result can also be seen in the pictures. In case you wonder what all these numbers mean to your sound experience, it's actually quite straightforward: mutual conductance directly translates to a tube's ability to amplify sound so the higher the numbers the better. 

Appearance & cosmetic condition

This pair is extra rare because at least 90% of the inscription (Amperex & Made in USA lettering and PQ logo) is well preserved, and the identical acid-etched Hicksville date codes are perfectly visible on both tubes:

7L5 *3I (7L5 = 6922/7308 production gen #5 , * = Amperex New York, 3 = 1963, I = September)


This pair of tubes will be packaged in the original Amperex tube boxes, secured by a handmade paper ribbon (by courtesy of Soundlumia.)
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