Amperex PQ 6922 vs Amperex PQ 7308

Amperex made a "regular" and a PQ version of the 7308 tube. I have a pair of each. The PQ version seems a little more extended at the frequency extremes, whereas the regular versions are more "midrangey"/"tubey".

Hope that helps.

There was also a military version of the 7308, no shield or PQ.

That said, if anyone is in need of some white or orange label Amperex 7308 PQ USA made I have a couple pairs I could part with. Also a single D-getter white label holland tube.

I've compared to a bunch of 6DJ8s (which are nice, and a lot more common), both are good but I'd rate the 7308 a fair bit higher.

-Ed

TVAD. Joe's mention of the description "shield" might refer to the "PQ" logo. It's a shield with the letters PQ and two stars inside. OR, he could be refering to the internal construction of the tube whether it's shielded or not shielded.

I have some 7308 PQ with the shield logo as well as JAN 7308 with no PQ logo. They are the same tube. PQ's were labeled for general consumers where JAN labels for the military.

The difference between the 6922 and 7308 is minuscule, to my ears.

IMNSHO PQ=shield, it's the graphic that is on the tube. Sorry if I wasnt' clear. I have only had PQ with shield logo, not any that are either/or.

generally 7308s are quieter and better matched. they are selected 6922s, essentially.

the consumer versions pre-date the military versions in general. Age is by color of printing to a degree. white, orange, green for printing colors, oldest to newest. usually they have date codes on them too.

as with most tubes earlier=better.

-Ed

TVAD,

To answer your question, only the PQ version had the shield logo. The other one has the green JAN label.

PQ and Non-PQ are the same tube. I've not heard consistant differences in sound between the two label types.

On the otherhand, in the gear I've owned, Amperex 6922 and 7308 sound quite different from one another. There is also a difference (in sound) between Holland and USA product with the same internal construction.

I've owned/tried approx. 100 various Amperex White label 6922's and 7308's in Audion and Consonance gear.

Same goes for Philips SQ and Non-SQ labels (based on sampling 20+ of their 6922's). They sound alike.

PQ = premium quality - it could just be a branding thing but then again it could be some extra selection for matched sections, etc. Likely impossible to say - much lore surrounding that sort of thing has been lost to the mists of time, alas.

-Ed

The Amperex 7308 was an attempt by manufacturers to make a tougher and longer lasting tube. This tube was made starting in 1959. The older the tube, the better the sound quality--or so they say. The white letter PQ with shield is the best sounding. They made a USA and a Holland version. The Holland is sapposed to be sweeter, but not quite as dynamic as the USA. Also, in 7308, they made an orange lettering/orange world globe logoed tube. I've tried this tube. It's better than the JAN green letter tube by quite a bit, but not as good as the PQ with shield. The JAN green letter is not as open as the two tubes above. Currently, I'm running four Amperex 7308 white letter PQ with shield in my Bat preamp. Good tubes make a huge difference.

I ran out of space on my last post-- As dogpile said JAN is military use. I've also seen JAN orange world globe logo tubes . I've heard that on earlier 7308 tubes, they may be white lettered only (and still be PQ) or they may be white lettered and say PQ but not have a shield. It's kind of a mess. Other manufacturers also put their label on these tubes as well. Sorry if I repeated some of the info repeated by others. Where's Joe when you need him? Dekay, have you tried any of the earlier 7308 Holland PQ tubes? How do they sound? Ive never had the chance to try any Holland version PQ's.

I hope that I didn't step on any toes by diving into this thread. I was just relaying what I've learned from Andy @ Vintage Tube Services and what I've learned in 6yrs of trial and error with small signal tubes. Ed- I read your review of the Shuguang/Super TNT 845B tube. It looks like you've been around tubes for a long time... as I said, I hope that I didn't step on any toes. Best! Stan

So,I ask,once again,which would you guys prefer in a phonostage.The PQ 7308 or the PQ 6922!!Thanks.

Also,since so many of you are quite knowledgeable,do you think I'm wasting my time,since I already own very low noise Ediswan 5358's that I'm using in my phonostage?Or,should I still be persuing a good set of PQ's?

I think that either the 7308 or the 6922 PQ would smoke the Ediswan tube. The 7308 would probably have more longevity and be a quieter tube than the 6922. I tried to Email this to you but I got server error messages. If you want a reccomendation of a good place to buy tubes, click on my system for my Email.
Best! Stan

Gotta agree with Talon4 and disagree with Dekay. There is a difference b/t the PQ and JAN versions. I prefer the PQ

Talon:

In general the Holland 6922's and 7308's are a bit softer sounding than their USA counterparts.

I usually prefer softer sounding 6922 types, but I ended up keeping only USA versions for personal use (so there are other subtle differences which I am unable to describe well).

I've read that PQ's were screened for close section match, but as mentioned I've never detected a difference between the PQ/Non-PQ versions I've gone through. I have both types sharing the same production/date codes (they are the same tubes).

JAN/USN, etc., were marked such for military purchase orders (same as tubes being marked IBM for IBM PO's, Fisher by Mullard, Telefunken tubes marked Pilot Radio Corp., etc.).

In all the gear I've used White label 6922's have fuller bass/mid-bass than White label 7308's. The 7308's have greater HF extension than the 6922. My preference is dependent upon the system they are being used in.

Never tried 7308's in a phono section.

The JAN- (Joint Army Navy) tubes that I've used were the 7308 Green Letter-1976 and the 7308 Orange Globe Logo-1967. The older the tube the better. I've never tried an older JAN tube like a 7308 white letter JAN-USN. I've heard that they are very good. So the difference between a JAN tube and a PQ depends on what year/type of JAN you have. I'd still rather have a PQ over a JAN-USN, but who knows, some JAN-USN could be PQ-Premium Quality, before lettering.(ie. the same tube) If I ever have a tube question that I can't find information about, I call Andy @ Vintage Tube Services. He's very knowledgeable. Dekay-- Thanks for relaying your experience with the Holland PQ tubes.It's a big help.

Well my friend(Ex friend/after he scored these tubes)just picked up a quad of NOS Amperex 6922 PQ for his phonostage.WE both have the same 3-tube phonostage.AS I've indicated,I RUN LOW NOISE EDISWAN'S HERE.I'll be going over to his home next week and we'll do a comparison.Will add thread as to results.I can't wait.We've already tried Mullard/TELE's etc.These new results should be fascinating.

Sir speedy, The premise that I use for the PQ being better than the Ediswan is both the placement of that tube in "Joe's Tube Lure"- (the order looks like average to best) and what Andy of Vintage Tube Services indicated on his website-(go to Inventory List, than "6DJ8-6922-7308"- read what he said in that descriptive boxed area heading.) I've never actually heard an Ediswan tube, so I'm going by my interpretation of what the experts have said. Also, in your 3/1 post, you did ask if you were wasting your time persuing a good set of PQ's. I'm sure that your Ediswan tubes sound good. But... I feel that a GOOD set of PQ's will sound better. Best! Stan

Sirspeedy.. Ediswan did not munfacture tubes. They are an English company that rebrands tubes sourced from many tube manufacturers and suppliers. I have a quad of ecc88's branded ediswan that are actually late 70's seimens. I also have Ediswann branded ecc 82's, ecc802's, ecc83's ecc808's and others. Some are Mullard made,some Brimar made, some eastern block german RFT's,some holland made etc,etc. The good thing here is your Ediswan tubes are non microphonic low noise preamp grade tubes. That said....chances are that any nos PQ labelled Amperex 7308 [white label, orange label, US manufacture or Holland maufactured tube should handily better your Ediswan labelled 6dj8's if they are non microphonic low noise equivalents. The early Holland made white labell ecc88's {both D-getter and O-getter versions} should walk all over your ediswans in every which way. Quiet examples of these tubes tubes are in a whole higher order than most any tube of it's type ever produced. Warm,smooth,great bass resolution with an airy soundstage akin to the hideously expensive siemen and telie CCA's. You haven't mentioned the Phono stage or catridge you are using and most modern phono stages are voiced with currently manufactured tubes so your mileage may vary with your choice of nos tubes. In my experience... Most any brand of pre 70's ecc88 family of tube will step all over any tube manufactured after 1980 regarless of manufacture. Note: Ediswan relabelled and reboxed sovtek 6922's as well as the 6h23ev. These are not the same tubes even though they were manufactured in Russia. The 6h23ev's were manufactured strictly for the Soviet military and were never ever seen until the fall of the BIG RED Machine. Now, I suppose they can be called nos tubes....none the less, they are very good souding valves, very linear with tight triode sections, great bass and the quietest tubes in the 6dj8 family. Not to be confused and no resemblence to the glassy,glarey sounding Sovtek 6dj8/6922.

Talon4,andEcclectique.Thank you for your responses.The phonostage/pre is a Highly Modded(by GREAT NORTHERN SOUND),actually rebuilt at quite an expense,but worth every penny,Audio Res. SP-15.Three tubes in phonostage.I previously owned CJ,AR sp8,sp10,sp11.I know the preference in the hobby for ALL tube units,but,I FAR prefer the GNS modded Sp-15 to any of my previous units.

That being said I and a friend have almost exact systems,his Kharma based,mine Avalon based.(modded SP-15's as well).We have tube rolled everything from dreck to overpriced DRECK(TELE cc a's here).The tubes that have so far come out on top are the EDISWAN(steel pin) and MULLARD gold pinn.I am aware that my Ediswans are British Mullards.These tubes were sold to me by Kevin Deal.From his Ultra low noise"secret stash",which can no longer be purchased unless you buy a major component from him.I have 6 in total.

The only way I will make a comment on a particular tube is from actually hearing it in either my own,or my friend's set-up.I know that you have meant well,but to make a recommendation based upon a reviewer's comments is like recommending a record from someone's Super Disc List.Would you recommend a speaker system,having NOT heard it,based upon a reviewer's opinions.They are JUST HOBBYISTS like all of us!!It is unreliable to recommend when not familiar,first hand.!!Please don't think I'm being rude I just feel that the ONLY info that is reliable is FIRST HAND LISTENING.Seems to me that this Joe's Tube Lore article(that I loved BTW)is like HP's Super Disc List,driving up prices on stuff that is only his opinion(in a CD based set-up,no less),highly specious.

I have also auditioned,and own a set(3)7308 Amperex non PQ.These are wonderful sounding,but the Ediswans I own are as rich in tonal balance and more dynamic,so as of now they are TOP DOG,for me.Next week I'll listen to the elusive Amperex White labe PQ 6922,in my friend's set-up.We'll compare these to the Mullard's he has(which trounced the Overpriced,3 different set's he bought
Thanks for the well meant intentions!!

Since I messed up my last post,due to a time constraint,let me add missing info.The 3 seperate sets of tubes we compared in my friend's set up,recently,were all CCA TELE,very low noise.The Mullards he has were richer,better stage,smoother.Maybe a drop less dynamic,but really killed the OVERPRICED TELES.in musicality.The only tubes we haven't tried are the Siemens.Supposedly very good,but the debate for him and me,ends this coming Friday,with the "Great Amperex vs Mullard/Ediswan Shootout".Maybe better stuff out there(actually,most likely there is),but the search will end on the 11th of March,for us.This stuff is getting too hard to find,and getting where you have a hard time really being sure of the sellers,of vintage tubes.We've been lucky,so far.BTW-we both have Transfiguration Temper-v(low output)cartridges.I'll follow up,but remember,it is only going to be the opinion of a couple(3)listeners.

In no way do any of us proclaim to be the "Last Word"here.Just a couple of passionate MUSIC lovers.Also,the systems that tubes are employed in,will obviously affect the perceived sound,so this is meaningless,other than curiosity,to all but me,and my pal's set-up!!

Oh,yea.Forgot to mention that we'll be sharing a good quantity of some Merlot during the 4 or 5 hour listening session,so,when I post any results they will probably be meaningless anyway,but I'll sure have a "Good Time"!!

Have a nice weekend,all!

Sirspeedy. Well said sir. Your experience with ARC phono stages mirror mine with the ARC gear. It's great to find a particular tube type that fits the bill and I concurr with your assessment of the mullards. Throughout the years with the arc sp-3a and sp-6, my preference with those 12ax7 based preamps was unilaterally with siemens 12ax7's and with the 8 and [particularly] the 10 it was unilaterally the early seimen e88cc's. Arc gear just seem to love the seimen tubes. Interesting though that the my first 2 tubes in the phono of my sp-10 are also Mullards due to their dead quiet noise characteristics. You may want to give the early seimens a go though. They are certainly my favorites in the phono of the sp-10. Best of luck

Sirspeedy, You didn't mention that your Ediswan tubes were actually low noise Mullards until your 03/05/05 post. An "Ediswan tube" could have been any of several brands. Low noise Mullards are fine tubes indeed. That being said, I'm still curious, How did the "Great Amperex vs. Mullard/Ediswan shootout" turn out? Did the Amperex PQ's hold thier own against the low noise Mullards?

I was sworn to secrecy,because of the possibility of further price gauging,but I have a BIG mouth,so here goes.Joe's tube lore is RIGHT on the money.I am shocked at how accurately he described the differences.We tried quite a few tubes.The Ediswans I have are fabs,but the PQ 6922's SMOKED everything we thru at them.I have NO 6922 PQ"s and am SICK!!The Mullards,by the way,destroyed the FAMOUS diamond bottomed TELES!!That is the regular MULLARDS.As did the Ediswans.

I'm going to get yelled at by my audio-crew for posting this,but I did promise.

Sirspeedy, I'm currently running 4 sets of matched low noise 7308 Amperex PQ with shield--circa 1963 and 1964-- in my Bat vk5i preamp. These tubes were bought from "Sam"-here @ audiogon and from Brenden @ Tube World. They both also carry 6922 PQ's. My tubes are still going strong after 1 years use. I would buy tubes again from either of these people. Also, I had two sets of these tubes checked out by Andy @ vintage Tube Services, a year ago, when I first bought them. He rated them as excellent with no microphonics. He said that they're the real thing. Just a recommendation of tube sellers, in case you may want to buy some PQ's. Best, Stan