Tube Equivalents > 6J1 > 6AK5 ?

kcoc321

While my Tube Buffer is in-transit, I have been researching tubes.

I made this list of equivalents for the 6J1's that the B-284 and the CD-2 use.
Thought I would post it in case someone else would find it useful. I am still new enough to this that I found it helpful to know the different options when looking at listings on eBay ect...

I am not an expert, so I can only say that "they" say they are eq's, based on what is listed on the Grant Fidelity Webpage here http://grantfidelity.com/site/B-283+Tube+Processor+Buffer

and using the search functions and the charts here

http://www.tubedata.info/usa2for.html

kcoc321

Found another good tube reference site:
http://www.nj7p.org/Tube4.php?base=7BD

Interestingly, they list the 5591 as another 'preferred substitute' for the 6Ak5's, it was not listed in the other sources I found, so far.

kcoc321

for anyone else looking for M8100's I found these on eBay, and they have quite a few.
They are NIB/ NOS for $20/pr, free shipping.


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270506323434&ssPageName=STRK:MEWAX:IT

description:
The CV4010 is the UK Government code for the commercial M8100 which in turn is Mullard's special quality version of the EF95/6AK5. This tube have 'R' code which is UK military code for Mullard. Guarantee NOS/NIB tubes in original bulk package.

**Now they don't 'say' M8100 on them, but I email him and he said they were the same.***


So are they the same (performance wise) as these for $16.15 each plus shipping???

EF95 CV4010 MULLARD VALVE TUBE



http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320221834729&ssPageName=STRK:MEWAX:IT

heiney9

The "R" has nothing to do with Military but it does mean they are Mullards and made in Mitcham Plant. The "CV" is a military designation, but not all CV's are for military use.

In fact the code on the 2nd pic of your thumbnail R1L3 means this tube was manufactured in 1971 at the Mitcham Plant by Mullard Radio Valve "L3" refers to the day/month or week of production.

The code is the only thing that really matters on a tube because a tube can have many brand markings. The tube code tells you where it was manufactured and when.

Looks like a very good deal based on the info you've provided. Stock up if he has good feedback.

Here's a good primer on Mullard tube codes

http://www.audiotubes.com/mullcode.htm

You also see "592" above the 4 digit code......"59" means it's a CV4010 and "2" means its the 2nd iteration of the CV4010

kcoc321

WOW. thanks....you really have this Stuff down...

Looks pretty good, regarding the seller, he is:

Top-rated seller
vintage_audio_lab ( 4058 [Feedback score is 1,000 to 4,999] )
99.8% Positive feedback

Get fast shipping and excellent service from eBay Top-rated sellers.

* Consistently receives highest buyers' ratings
* Ships items quickly
* Has earned a track record of excellent service

concealer404

What's the difference between those and the CV4010s i already grabbed for us?

heiney9

concealer404 wrote: »

What's the difference between those and the CV4010s i already grabbed for us?

Probably nothing, but what are the codes for the ones you already have. Tube codes are the ONLY reliable way to find out when and where tubes were manufactured simply because there are all different branding and markings going on. For example when you run across Harmon Kardon tubes, they never made tubes.......they brand someone else's tubes.

H9

concealer404

Ah... i'll have to check when i get home from work.

So it's possible that CV4010s are the same thing as M8100s? That's interesting.

heiney9

concealer404 wrote: »

Ah... i'll have to check when i get home from work.

So it's possible that CV4010s are the same thing as M8100s? That's interesting.

They are, yes. As an example: Just like a 12AT7, ECC81, CV4024, M8162 and CV455 are all the same tube, just from different manufacturer's and parts of the world.

12AT7 is the "American" designation

ECC81 is the "European" designation

CV4024 is either a Mullard or Brimar, but they can be made at 5 different plants or more. Also and ECC81 could be a Mullard made tube based on the manufacture code. Lots of variation here based on logo's and tube numbers. One thing that is constant is the factory markings. I've also seen CV4024 with Valvo logo's.............guess what it's not a German tube it has the same code(s) as the other 4024's. Even Telefunken made tubes for other manufacturer's and the same goes for other manufacturer's making tubes for Telefunken. You can tell by the code and the absence of the "diamond" mark on the bottom of the tube

One could have a Philips, Amperex, Siemens, Valvo, Brimar, Mullard tube all with the exact same factory code.......meaning they are all the same tube just with different brand markings.

H9

concealer404

Ah ok...

Well, these are what we got:

http://cgi.ebay.com/SLEEVE-OF-FIVE-5654-6AK5W-6096-CV4010-TUBES_W0QQitemZ150258060327QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item22fc140c27

heiney9

concealer404 wrote: »

Ah ok...

Well, these are what we got:

http://cgi.ebay.com/SLEEVE-OF-FIVE-5654-6AK5W-6096-CV4010-TUBES_W0QQitemZ150258060327QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item22fc140c27

Tube codes are usually toward the bottom in smaller script and consist of 3 characters over 4 characters. They do vary a bit for tubes before 1959. Sometimes these marks are wiped or smudged and not readable too.

H9

concealer404

heiney9 wrote: »

Tube codes are usually toward the bottom in smaller script and consist of 3 characters over 4 characters. They do vary a bit for tubes before 1959. Sometimes these marks are wiped or smudged and not readable too.

H9

Got it, i'll update when i get home, then. I appreciate the teaching.

kcoc321

Wow, can't wait to see if we picked up a couple of Picasso's for Godwill pricing...
well, not quite, but still....

"Find the R, Find the R, Find the R"....hehe

heiney9

Actually a "B" would be better as that means it's made in the famous Blackburn plant or a "delta" sign meaning it's made in Heerlen Holland. "R" and the Mitchim plant are pretty common. Still a nice sounding tube however

concealer404

Arg... i really can't remember. These suckers are pretty old though... the original sleeve was no longer even close to white... pretty deep yellow of decades old cardboard. I wasn't expecting that for some reason, and it was pretty neat to a first time tube buyer.

heiney9

In my experience the older the tube, generally the better I like the sound. I have some tubes form the late 40's that are to die for.

kcoc321

I emailed the seller to ask if he could tell me the 3-digit over 4 digit code, and if he had any pictures.

Ben, have you sent my half of the set yet, btw?

concealer404

Sorry man, i didn't get a chance yesterday. Monday at the latest, though. If i can get out of work before the girlfriend has to work tomorrow i can get them to fedex tomorrow.

These tubes have on them:
CV4010
5654
6AK6W
6096

Guess those are all the equivalent number thingy-ma-jiggers.

The only other characters are:

RL-D
SDA
KH23

(EDIT)
Hrmmm...

Got a bunch of mismatches maybe?

Here's what we've got:

(2) RL-D SDA KH23
(1) RL-D SDA KH46
(1) SD-D SDA LD4
(1) RK-D SDA KJ5


WTF? I'm so lost.

concealer404

KC, i'm going to send you the exact matched pair. I think i may go on a buying spree once a couple Paypal things get cleared up, so i'm not REAL worried about what's in there now.

kcoc321

Not to worry, any pair are fine by me. I am sure they (the original buyer) got them from different places. They all still work, I think.

More importantly for a "matched pair" to have the same reading, rather than the same mfr info, I would guess. (well maybe once they are from the same mfr)

Check H9's post #4 again.
He is referring to the 3-digit and 4 digit numbers in the 2nd picture I posted.
Looks like hand written, in one of those silver/ dark grey liquid marker type pens...
see that?
that's what we're looking for...

I am sure one of the "guru's" will chime in here shortly, and help yo out...

Pictures would help...otherwise, I am still shooting in the dark,
but I would guess that the "KH23" = "?" unknown(on the link H9 posted above)
So they don't know either....LOL

the rest is just 'date made' info, I think....

Hey they sound good, right?

concealer404

Yeah, none of them have the handwritten stuff on them. Must have rubbed off. I'll still send you the pair, and yes, they do sound good.

As they're breaking in more, i'm not 100% sure if they're what i'm looking for, but they DO sound good. I'm going to put some more hours on them, they sound a little brighter than i was hoping for, but i've only got about 15-20 hours on them so far, so my fingers are crossed.

EVERYTHING else about them was a large improvement over the stock Chinese tubes, even right out of the box, though.

kcoc321

You should put the pair of RL-D SDA KH23 in your rig, NOW, and get them burned in.

Send me the (1) RL-D SDA KH46 & (1) RK-D SDA KJ5 (I am just guessin the "R" is the same mfr)
Keep the (1) SD-D SDA LD4 as "the spare" for whomever needs it...
KC

concealer404

Alright, i'll give that a shot, then. The two you picked are the ones that are in there right now, so they'll have about 20 hours on them already when you get them.


(EDIT)

Alright, they're in, and DMB is on and cranked. Impressions to come.

concealer404

Well, Dave is about 2 feet in front of me, out in front of his band, and his voice is SIZZLING.

Oh, and i didn't have the two "R"s in there before... i had an "R" and the "S" so i guess that may have done it. I hope the "R"s work well for you.

kcoc321

So do the "R's" sound better, than the "mixed" set?

concealer404

Don't know yet... If i can't ship them out tomorrow for you, i'll pop in both "R"s and see how they sound together. Even with the mismatch i had in there before, it was a nice improvement over the Chines 6J1s anyways, so we can only go up from there.

kcoc321

Weel, I emailed the seller and we at least know why these have different numbers:

KC,
These tubes were bought as mil surplus and they were all dumped in to a large container when shipped to me. I will open some and see if I can matched them up.
Frank

zingo

Thanks for creating this thread KC. I just got a HiFiMAN EF2 USB Headphone Amplifier, and it too uses a pair of 6J1 tubes. I had been looking for equivalents, but it looks like you did the work for me.

kcoc321

Cool, I thought it would be helpful to more than Ben & I. What tubes are you looking at?

zingo

None yet. I just got the amp in and figured there were better options than Chinese tubes. I'll show you at our meet.

concealer404

kcoc321 wrote: »

Weel, I emailed the seller and we at least know why these have different numbers:

That's interesting, actually... i'm almost tempted to see what kind of deal he would give me on say... 50 random tubes just to see what we could get. These ARE definitely sounding different. I'm still not 100% sold on them, but they've got some breaking in to do yet.

The highs are just a little too pronounced for me. I actually prefer the 6J1s in that regard. Everything else is a clear win for the CV4010s, though.