I just got the 12BH7 and think it is a nice sounding tube. I really have not heard any tube that makes the Crack sound bad. There are just some tubes that make it sound great. The 12BH7 reminds me of a Sony TV in that it make it gives the sound a bloom with good separation. It does nothing wrong it is just that I like,not my ears the natural sound of the CBS 5814A tube. This has been my favorite tube so far, but will be spending more time with the Sylvania 12BH7.
Tube Rolling w/Crack
- Thread starter Dr. Toobz
- Start date
Rolled in a NOS RCA 12bh7a and an Tungsram E80CC. The RCA is a great sounding tube maybe the best of those I've tried. The Tungsram E80CC not so great. It sounds a little harsh to me with HD650's. It lacks the warmth of the other tubes I've tried. I'll give it a little time before passing final judgement.
The last NOS RCA 12bh7a I purchased was $3.29 plus $5.00 shipping. So there are some deals out there if you can find them. I'll have to revise my opinion of the Tungsram E80CC. It just needed a little more time to burn in. Very nice sounding tube after all. Nice wide soundstage and very detailed mids. I'm running out of tubes to try and mods for the Crack. Must be time to build a different Bottlehead kit. Now which one?
Hey all, This is a dumb question but I'm desparate....I got a 5998 that glows but no sound comes out. Again, it looks fine! Any chance it might be fixed with a some home remedy/vodoo. I'm totally bummed about this. $100 off ebay and it worked an hour. I turned on the crack, and before I got the headphones on I heard a load crackling sound...then nothing.
Presumably you have verified that the amp still works fine with the original tube. If that is the case, the only thing you can fix would be to clean the pins and check to see if the tube socket contacts are tight. If it's a problem inside the tube it's time to contact the seller.
Bummer John, they are hard to come by for any semblance of a reasonable price these days. Hope it's a decent seller who will do right by you and refund the money. I got 2 used from Brendan at TW a few months back. Both were listed used, tests as new. One had a white arc between plates at fire up and then intermittent arcing with static in one channel while it was occuring. Brendan exchanged the tube for the last one he had. Also a used, tests new. I was fortunate to pay $35 and $32 for the two I have from him and both tubes look pretty close to NOS. Those are my spares as Im using one that forum member Jim (Jrebman) was kind enough to let go of for a very fair price before I found those two.
I look forward to your comparison with the 421A if you get another 5998. One of my 5998's has the clear top (like the WE 421A) and I can tell you that I can hear no difference between it and the flashed top versions. Not saying that a clear top 5998 is a 421. I have read that all the slight internal variations of the Tung Sol 5998's sound the same, just confirming that with what my ears hear in case you come across one of the different versions.
I look forward to your comparison with the 421A if you get another 5998. One of my 5998's has the clear top (like the WE 421A) and I can tell you that I can hear no difference between it and the flashed top versions. Not saying that a clear top 5998 is a 421. I have read that all the slight internal variations of the Tung Sol 5998's sound the same, just confirming that with what my ears hear in case you come across one of the different versions.
Thanks. He said on the listing that no refunds were accepted...soooo, I asked if he would consider a partial refund and he said he could. It did become clear that he was not going to suggest anything as for amount, so I kicked it off by asking if he could do a 50$ refund, which he accepted once I sent it back (posted today). He did let me keep the original Tung-Sol box though! So, I got a box for 50$...more than u paid for your tube...sad. But hey, win-some-lose-some. He could have just blown me off though, then I'd have to give him a fairly low rating.
Let me know if you find more at that price!!
Let me know if you find more at that price!!
Noskipallwd
New member
Hey guys, I rolled an e80cc into my crack about a month ago, and yes it was a little harsh an shrill at first. After 25-30 hours it began to smooth out, now I am loving it paired with a 5998. I also listen with HD650s. Plus it is a rather beautiful tube. So give it some time you might find you like it
Cheers,
Shawn
Cheers,
Shawn
Noskipallwd
New member
Brad, I have two Phillips Miniwatt SQ E80CC, they can be expensive as heck. I traded tubes and cash with a friend. Not sure where he bought them but the tubes and the origiinal boxes look like they came off the assembly line yesterday. I also put one in my Hagerman CornetII phonostage and it made a significant difference in this amp as well. Finished my eros a couple of days ago though, and after listening for quite a few hours I don't think I will be listening to the Hagerman much anymore. I saw you posted you like the CBS Hytron, it is a great tube in thee Crack, plus as a side benefit it actually glows. It was my favorite driver to date but I think the E80CC might have supplanted it.
Cheers,
Shawn
Cheers,
Shawn
jrihs said:
50 bucks is better than nothing. Ebay definitely can getcha. In recent memory, had a very weak 6AS7 that was supposed to be strong, a dead 12BH7 and a 6SN7 that went dead within a few minutes. They were all dirt cheap but it's still money down the drain. But many more good finds than lemons so I keep rolling the dice. I was a bit bummed on the 6SN7 because it was a relabeled Sylvania VT-231 for dirt cheap. Win some, lose some.
Will do on the 5998's.
nick-seattle
New member
Hello eveybody, I'm now on Crack like a lot of you 
I tried many tubes in the amp, but unfortunately it only works well with 12au7 family and 6sn7. Also 12bh7 and 6gu7 appear to be working well. Now to the question, I want to try 12ax7 in the amp - I have a lot of them - Telefunken, Mazda and other European brands - US brands that sound just phenomenal. What should I do to make the rolling of the tubes adjustable - I'm planning to roll a lot of them
I tried many tubes in the amp, but unfortunately it only works well with 12au7 family and 6sn7. Also 12bh7 and 6gu7 appear to be working well. Now to the question, I want to try 12ax7 in the amp - I have a lot of them - Telefunken, Mazda and other European brands - US brands that sound just phenomenal. What should I do to make the rolling of the tubes adjustable - I'm planning to roll a lot of them
Paul Joppa
Moderator
In a word, you can't.
Well, nothing is impossible, but to do so you must operate at extremely low plate current and at a bias uncomfortably close to Class A2. The low current means marginal drive at high frequencies (distortion and anemic treble) and the low bias means potential distortion as the grid current loads the volume control with a nonlinear impedance.
Starting point - replace the LED in the cathode with a silicon diode, to give around 0.7v bias. Use a small signal diode, not a rectifier diode. Then increase the plate load resistor from 22K to 220K - but experiment with that value to get ~70v on the plate. If you have the speedball, increase R1 to 1700 ohms to get 0.5mA current.
Well, nothing is impossible, but to do so you must operate at extremely low plate current and at a bias uncomfortably close to Class A2. The low current means marginal drive at high frequencies (distortion and anemic treble) and the low bias means potential distortion as the grid current loads the volume control with a nonlinear impedance.
Starting point - replace the LED in the cathode with a silicon diode, to give around 0.7v bias. Use a small signal diode, not a rectifier diode. Then increase the plate load resistor from 22K to 220K - but experiment with that value to get ~70v on the plate. If you have the speedball, increase R1 to 1700 ohms to get 0.5mA current.
nick-seattle
New member
Thank, Paul. I will stay away from this kind of mod for now - need to roll all the 12au7, 6gu7 and 6sn7 tubes first
BTW, I'm posting results of rolling on www.tubemaze.info
First couple of 6as7 tubes for Crack:
http://tubemaze.info/svetlana-6as7-6%D0%BD13%D1%81/
http://tubemaze.info/raytheon-jan-6080/
Will also post review of Raytheon 5814 Windmill getter today - hope it sounds as good as advertised
BTW, I'm posting results of rolling on www.tubemaze.info
First couple of 6as7 tubes for Crack:
http://tubemaze.info/svetlana-6as7-6%D0%BD13%D1%81/
http://tubemaze.info/raytheon-jan-6080/
Will also post review of Raytheon 5814 Windmill getter today - hope it sounds as good as advertised
