Tube Variants

S

shanman

New member
After trying a number of tube variants I've come up with a combo that really is a pleasure to listen to:

RCA JAN 5014A black plate - warm mids, good bass and refined highs that don't fatigue the ears.
RCA 6AS7G

I went with the AXON 90uf coupling caps and after about 20 hrs of break in they sound great thru my Senn HD580 phones.  Feed them some hi-def audio and enjoy.
 
I'm not familiar with all of it, but that 5014 has always been one of my favorites, and AXON caps are always a good choice in my experience.

Enjoy!
 
The tube I had intended to recommend (before my fingers failed me) is the RCA 5814A.  Many of the 12AU7 types I auditioned are very detailed/accentuated in the high end, giving the impression of super clarity and imaging.  Though interesting at first listen, it didn't take long before this characteristic distracts from the music and is tiring to the ear.  The 5814A was a warm and welcome relief.

Crack was my first tube kit build and it was certainly worth the effort. Amazing sound from a such a basic circuit. 

I'm looking for new tube head-amp kit to build and came across John Broskie's "Aikido" (PCB based) amp. If anyone has any experience with this kit, I would be eager to read your opinions.
 
I knew exactly what you meant and even copied your typo!  My eyes must have been more tired than your fingers!  Hilarious!

But, back when I was rolling tubes in a Foreplay 2, I landed on the 5814A, too, although I never took the time to try to articulate why.  I have since laid in a small supply of them.  I don't recall if they are the JAN version, but I have never run across anything I liked better.  I think there was a time when RCA was turning out so many tubes that their consistency was way up just from sheer numbers.  Whatever the reason, I now have used them in a couple of pre-amps and several customer guitar amps (yes, not every guitar amp uses high-mu tubes everywhere).  And, of course, my RCA VTVM uses one!
 
Well after taking my sweet old time, I've finally finished building the Crack and Speedball upgrade. What a sense of accomplishment (it's my first ever foray into DIY and I'm already a self-confessed addict!)  I still haven't finished putting the wooden base together so the innards of the amp are sitting on my bedside table, but man oh man does it ever sound good!  Compared to my Darkvoice 336, it just sings with the HD650s!  I've only got a few hours on the Crack so far, so it hasn't been fully burnt in, and I'm sure it will only get better with age.

I'm planning on upgrading the 12AU7 (I've already swapped the 6080 out for a 5998) and would like to buy 2-3 quality tubes but not spend too, too much money on them.  There are so many choices for 12AU7, but I was leaning towards one or some of the following:

* Siemens 5814A (is there a big difference b/t 1960s and 1980s?)
* Mullard CV4003
* RCA clear-top 12AU7A
* maybe splurge for a Telefunken Germany (not sure smooth or ribbed plates)
* maybe splurge for a Amperex 7316 (not sure tall or short plate)


If anybody could offer their insight (especially when paired with the HD650s) or other suggestions, I'd really appreciate it.

Enjoy the music!
 
Recently tried a CBS Hytron 12BH7 and was pleasantly surprised by an enhanced soundstage, dynamics and definition when compared to the 5814.  Bass is solid and well recorded instruments and vocals (i.e. Allison Kraus) provide a holographic presentation. Still the sound is somewhat "forward" and I'm thinking the questionable linearity of the 6AS7G may be the cause. 

I'm considering rolling in a 6BX7 for the output (trading output impedence for linearity) and was hoping someone might have some first hand results with this tube.
 
I too settled in on a 5998 after several months with an RCA 6AS7.  The bottom end has more heft with it.  I've been using an Amperex Bugle Boy 7316 with both of these after cycling through the Seimens ECC802S (good, but just not AS good), Mullard 4003 (a little muddier).  I love this combo!
 
Are the early 60's Sylvania 7236 metal bases very similar to the Tungsol 5998s ?

I've just discovered I had an EH modern production 12BH7A lying around from a low powered guitar amp I used to have.
Sold the amp with an old RCA 12BH7A :-(  Interesting, very  palpable. Have ordered another old RCA 12BH7A to try.

Cheers,

John
 
Raksasa said:
Are the early 60's Sylvania 7236 metal bases very similar to the Tungsol 5998s ?
Click to expand...

I just found from a tube seller website that:

(7236=Computer rated 5998A)

Cheers,

John
 
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