Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders.

---

[ Follow Ups ] Thread: [ Display  All  Email ] [ Tube DIY Asylum ]

---

[ Alert Moderator ] [ Edit ] [ Delete ]

---

Amperex 6922 vs RCA 6CG7 vs RCA 6FQ7 'clear top'

69.29.11.17

Posted by Jimmy on June 11, 2005 at 11:44:15

Constantly & relentlessly trying to improve the 'poinz' PP 6V6 triode connected amp, I have come insanely close to the performance of a $2K in parts PP45 amp. New owner of these 45 amps states best ever heard & quite a few well known 'brand' name amps been auditioned in their audiophile quality system including other 45 designs. The speakers are Tannoy and mate well with PP45s. Anyways, that speaks a lot for the PP 6V6 amp as I heard both- thanks Eric.

Auditioning the subject tubes above, I though it would be of interest in the phase inverter position of the 'poinz' design. I been thru a few different 5965 tubes including the well regarded Amperex E180CC 'pinch waist' & the Amperex PQ 7062. The Amperex 6922 is superior to any 5965 family or any simular Amperex, but requires a preamp for full output in this circuit. remember, this circuit is not your circuit & the E1800CC is high quality tube as others reported.

Amperex PQ 6922 'gold pin'
This tube has the large top ring getter with a splash shield (not 'A' frame) manufactured in 1968 (USA). The 'A' frame type did not produce near as good results in this circuit.

The Amperex 6922 produces the strongest bass of the three tubes. The bass is reasonably controlled, but not tight nor bloated. The midrange & high frequencies are on the warm side and airy sounding. I also tried Amperex 7308 & they sound identical to the Amperex 6922. As always, the soundstage is wide with plenty of black in-between instruments.

RCA 6FQ7 'clear top'
I am aware a few different versions of these tubes exist. This tube has the grey plates & a round side getter. I also tested the RCA 'clear top' with a square side getter & identical grey plate design. I could not hear any difference in-between the tubes.

The RCA 'clear top' bass volume is less than the Amperex 6922 and this is not due to less gain of the 6FQ7. The bass is tightly controlled without any congestion & still ample for all the program material I use in my audio system. Perhaps some older rock music might be better with the Amperex 6922 response, however it would depend upon the speakers. The midrange and the high frequencies have more detail and are slightly more forward than the Amperex 6922. No doubt these tubes are brighter in the upper mids & high frequencies than the Amperex 6922. Others have stated too bright, but I find some minor congestion or perhaps better described as a minor compressed sound in the upper mids & highs.

RCA 6CQ7 'shielded'
This tube has the non-shiney ribbed black plates & small square top getter. I also listened to a pair with identical plates & larger horseshoe type getter. Both tubes sound identical. The bass is the about same as the RCA 6FQ7 'clear top', perhaps just slightly stronger. The midrange is as detailed as the RCA 6FQ7, but more open without that slightly compressed sound. Again, is the bright sonics of the 'clear top' reported by others actually that slightly congested sonics as I hear the tubes?

Anyways, the RCA 6CG7 are clearly the winner in my circuit. I would have no issues paying $40 a pair for NOS RCA black plate & I will purchase four more of the RCA 6CG7 as these tubes are getting more difficult to find.

Keep in mind, the most confusing issues of reporting sonics are tubes perform differently in different circuits. Your audition may differ than the results in my amps. A special thanks to others for recommending these RCA black plate tubes to me.

This post is made possible by the generous support of people like you and our sponsors:

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---