Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: mikek200 on April 29, 2013, 11:02:27 AM
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Has anyone done a comparison between these two tubes?
Are there ,any real audio differences?
Any insight,opinions,will be appreciated..
Thanks
Mike
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General consensus is that the 421A is a "premium" 5998 with matched sections and does have slightly better dynamics and technicalities. However, whether it is worth the much higher premium (around double the price of a NOS/NIB 5998) is up to you. On the other hand, many believe that the two are essentially the same tube, although the 421A is always found to have double bottom halo or double bottom D getters. Construction wise they are otherwise identical. If you looked up the internet, you would find that both of these tubes have glossy black and matte black/grey domino plates. Reason being that they are possibly the same tube is because some 421A tubes were in fact marked "5998/421A" (link) (http://www.bottlehead.com/smf/index.php?action=dlattach;topic=3453.0;attach=2377) Some would say that a well matched 5998 is essentially the same as the 421A. If you haven't already done so, you could take a read at my 6AS7 rolling guide down below at my sig.
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It is indeed entirely plausible that WE had Tung Sol make the 421A for them, but requested the extra getters as part of their design specification.
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Being WE, they may also have specified a level of matching, with Tung-Sol selling off the rejects as 5998s. I have heard that in the early days something like 75% of 300Bs failed to meet test standards and were destroyed at the factory.
I have also heard that one of the tests was to connect the 300B to a socket at the end of a 3-foot cable, so it hung upside down. Then fire it up, pull the tube back so it hung at an angle (45 degrees?) and let go - smashing into a concrete wall. Now there a SEVERE microphonics test!
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Thanks guys for all the input...
Turns out my bid,on e-bay was accepted..
next question,you might ask---don't ask.,yes, extremely expensive,the most I ever paid for a matching set of tubes,even the famed Lorenze Stuttgarts,when I had the Lyr amp
When I get delivery,I will do an A/B comparison against my TS 5998's
Might have been a little too anxious on this purchase.
Tnx
Mike
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I've tried 3 tubes Tung-Sol 5998, WE 421A O-getters and WE 421A D-getters. Sound signature of the tubes is practically identical. WE tube do have a more airy feel - that could be explained by a very careful selection. WE doesn't really worth 2-3x of Tung-Sol. It's just the idea of having the best of the best that drives people to buy these tubes. The same is with many other tubes that were made by WE vs other manufacturers - there is usually no might and day difference.
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I acquired a WE 421A and have given a good listening for a few days, maybe a total of 20hrs. I'm comparing it to a Tung-Sol Chatham '57 5998. The 421A was built in '77. In my case the 5998 has more air, depth and that je nais sais cois. They say with tubes the older the better. But I think possibly that that material selections got really good in the 50s and 60s.
IMHO, in my case its not going to be worth holding onto the 421a. Given its cost and possible performance dip, I'm planning to sell it.
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I acquired a WE 421A and have given a good listening for a few days, maybe a total of 20hrs. I'm comparing it to a Tung-Sol Chatham '57 5998. The 421A was built in '77. In my case the 5998 has more air, depth and that je nais sais cois. They say with tubes the older the better. But I think possibly that that material selections got really good in the 50s and 60s.
IMHO, in my case its not going to be worth holding onto the 421a. Given its cost and possible performance dip, I'm planning to sell it.
Interesting I tend to favour my early 1950's Tung-sol 5998's with the single getter over my later twin getter ones the coating on the plates looks different there is a dull coarseness to them while the later ones are smooth and shiny. I cant quiet put a finger on why I prefer one over the other.
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I acquired a WE 421A and have given a good listening for a few days, maybe a total of 20hrs. I'm comparing it to a Tung-Sol Chatham '57 5998. The 421A was built in '77. In my case the 5998 has more air, depth and that je nais sais cois. They say with tubes the older the better. But I think possibly that that material selections got really good in the 50s and 60s.
IMHO, in my case its not going to be worth holding onto the 421a. Given its cost and possible performance dip, I'm planning to sell it.
Interesting I tend to favour my early 1950's Tung-sol 5998's with the single getter over my later twin getter ones the coating on the plates looks different there is a dull coarseness to them while the later ones are smooth and shiny. I cant quiet put a finger on why I prefer one over the other.
Yeah! And I've got this dirt cheap pair Tung-Sol 12AU7 50's...just gently broken in. They just work. I'm floored about how cheap you can find them on ebay and how well they perform compared to what I've tried so far in the driver section. Floored I say. :P I mean $5 for the pair. Cost more to ship them at a lousy $7.
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Yeah! And I've got this dirt cheap pair Tung-Sol 12AU7 50's...just gently broken in. They just work. I'm floored about how cheap you can find them on ebay and how well they perform compared to what I've tried so far in the driver section. Floored I say. :P I mean $5 for the pair. Cost more to ship them at a lousy $7.
Is the 12au7 Tung sol a JTL? nice tubes.
Here is my latest ebay bargain today
Mullard-CV-4003
Item condition:New
Ended:25 Mar, 2014 13:31:30 GMT
Winning bid: £1.40
Postage:£4.10 Standard Delivery
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JTL?
Good catch on the CV4003. I got one on the cheap too, but its a 6067/4003. So I'm uncertain if it's the real deal. I'm not all that fond of it, so likely not.
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What's "JTL" mean?
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What's "JTL" mean?
Military procurement acronym for Joint Theater Logistics. Similar to JAN, Joint Army Navy.
Cheers,
Geary
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The curves for the 5998 are different than those for the 421A (GE vs WE specifically).
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I have had both and I am using the WE right now. They are both very good and for my taste better than any 6080 I have tried. The WE is a little clearer sounding and seems to let you hear a little more into the recording. The tungsol was very musical to me though. These are minor details as they were very close. For what it's worth the WE was a little quieter in my system, but I am using the Crack/speedball as a preamp. Enjoy your new tube I think you will be happy with it.
FWIW I am using a Mullard CV4003 box plate with it.
Ritchie
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I have to reserve the right to change my opinion. Apparently. :P
I was doing up the WE 421a for ebay and dropped it a couple inches. So I had to put it back in to ensure it was working, even though I was certain nothing happened. Well, I'm now on my 5th switch between the tung-sol and the WE with a couple test tracks. I have to agree with the above exactly! The tung sol is slightly more musical and the WE more technically astute - pulling out more soundstage and detail.
I didn't want to believe it. But when I'm listening to spatial effects on the 421a, it forces my eyes to move around where the 5998 not so much. I've only given this WE less than 20hrs, so I think its time to give the full 100hr break-in treatment and enjoy.
Plugging in CV4003 now.
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This experiment is not complete unless you drop the 5998 too.
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This experiment is not complete unless you drop the 5998 too.
Good one there, Doc. Any further assessments of the difference between the two tubes since your epiphany in March, Nightflight? I'm in the market for the Tung Sol 5998, and would appreciate being pointed in the right direction to purchase one outside of eBay. There seems to be a shade too much shadiness around transactions there.
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If you can find a 1950s 5998 clear top grab it quick its defiantly a level or 2 above both my single and twin getter 5998s and I would go so far as to say I prefer it to the WE421a. With the clear top the 5998 essentially it looks near identical to the WE421a and I would say its a good mix of combining both the detail and musicality of the two separate tubes.
(https://www.head-fi.org/content/type/61/id/1123319/width/350/height/700/flags/LL)
For non ebay Vacuumtubes.net regularly seem to have 5998's in stock @ $85
http://www.vacuumtubes.net/RES%20Audio%20pages/5998.html
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For non ebay Vacuumtubes.net regularly seem to have 5998's in stock @ $85
http://www.vacuumtubes.net/RES%20Audio%20pages/5998.html
A few weeks or so ago, I called vacuumtubes.net and was told they had only a couple of highly microphonic 5998s left. The gentleman I spoke with said that he wasn't even sure he wanted to sell them. He did not know if or when they would be getting any more.
I mention this to prevent disappointment among those eager to acquire 5998s. But if I'm behind the times, and if you've heard that vacuumtubes.net has a new stash of good 5998s, please spread the word!
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That makes a refreshing change and is good to hear.
I noticed there has been quiet a few nos 5998's turn up on ebay over the weekend from a US seller.