NAD & tube question

[JB_From_Hell]

Did some trading, and wound up with a Blackstar HT Club 40. After playing awhile, I'm getting a low pitched hum. Am I correct in starting with new power tubes? If so, does anybody recommend any specific tubes? It has two EL34s, and two 12AX7s (may as well replace those, too).

 

[beaubrummels]

I thought hum was filter caps?

 

[JB_From_Hell]

It's intermittent, and goes away if you bang on the amp. Also, if it's not humming, banging on it is audible. Gonna take the back off and see if something is loose.

Aside from that, it's pretty easy to get a good metal sound out of it. Chuggz galore plugged straight in.

 

[JB_From_Hell]

Found the problem. Opened it up, pulled out the tubes, one of the EL34s is messed up. A small bent metal piece (looks like a shield of some sort) is broken loose. Did a bit of looking, think I'm gonna try JJs because they're "cheap," and people seem to like them for metal.

 

[JMP/HBE]

Beware of "cheap" vacuum tubes, thats basically why you have a problem now.

 

[LRS]

JJs may be inexpensive, but they’re robust tubes usually, IME. They might sound a tad darker than the average Russian tube, but that’s a matter of taste. Definitely worth a try.

 

[Rex_Rocker]

JJs may be inexpensive, but they’re robust tubes usually, IME. They might sound a tad darker than the average Russian tube, but that’s a matter of taste. Definitely worth a try.

Not all, IME.

ECC83S's, yes.

ECC803S's, not at all. Those are plenty bright.

Their power tubes tend to be sizzly as well. Not as high-mid focused as (most) Russian, but they tend to be have a nice detail in the top end.

It's just their ECC83S's that give them the reputation for being dark... but if you look at the rest of their lineup, that's not really the case.



I still personally prefer a combination of Russian and Chinese in the premap, and Russian in the poweramp.

And also, I tend to avoid their E34L's that everybody seems to love. They're basically just off-spec EL34's that run hot. Many amps cannot handle them. They destroyed my Peavey XXX.


Also, that's on a general overgeneralizing basis. NS Mullards are pretty dark compared to EHX's.

 

[JB_From_Hell]

Not all, IME.

ECC83S's, yes.

ECC803S's, not at all. Those are plenty bright.

Their power tubes tend to be sizzly as well. Not as high-mid focused as (most) Russian, but they tend to be have a nice detail in the top end.

It's just their ECC83S's that give them the reputation for being dark... but if you look at the rest of their lineup, that's not really the case.



I still personally prefer a combination of Russian and Chinese in the premap, and Russian in the poweramp.

And also, I tend to avoid their E34L's that everybody seems to love. They're basically just off-spec EL34's that run hot. Many amps cannot handle them. They destroyed my Peavey XXX.


Also, that's on a general overgeneralizing basis. NS Mullards are pretty dark compared to EHX's.

I need two EL34s. You know what kind of sound I'm after, so what should I start with?

 

[Rex_Rocker]

I need two EL34s. You know what kind of sound I'm after, so what should I start with?

EH 6CA7's.

 

[beaubrummels]

OMG you hear the microphonics going on in that vid? (Obviously it's the pre, but how can you run a test like that?)

6CA7EH are brighter and tighter than typical Mullard EL34 types. My Orange AD50 came with 6CA7EH. Traynor YBA-1 came with 6CA7s stock in the 70s, and my understanding is EVH had 6CA7s in his VH1 variac'd Marshall.

The TAD EL34STR is also closer to a 6CA7 in design - they are big bottles and really handle it. (TAD = Tube Amp Doctor)

TungSol 6L6 are really closer to 5881, which are great sounding. Many Marshalls came with 5881s in the 80s, though my SL-X came with Tesla EL34M.

 

[Rex_Rocker]

my understanding is EVH had 6CA7s in his VH1 variac'd Marshall.

Correct. Sylvannias. EH's are supposedly recreations. How true that is, I wouldn't know. I haven't tried the real deal. But I'm not usually an EL34 guy and thought the EH 6CA7's were a cool middle ground between EL34's and what I actually like, 6L6's.

TungSol 6L6 are really closer to 5881, which are great sounding.

AFAIK, it was the JCM900's in the 90's which came with the Sovtek wafer-base 5881's, which aren't really 5881's, but another Russian military variation that withstand higher voltages than 5881's, but that put out less wattage than 6L6's. Again, not much of a NOS tube conossieur, but I've had all Sovtek 5881's, Tung Sol RI (not actual TS's from the 50's) 5881's, and NS Tung Sol 6L6GC's, and they all sound different. The Sovteks have a raspy high-mid emphasis and scooped lower mids. The TS 5881's have a tighter/leaner bottom-end, balanced mids, and some sparkle up top, and the TS 6L6's are darker and fatter.

The TAD EL34STR is also closer to a 6CA7 in design - they are big bottles and really handle it. (TAD = Tube Amp Doctor)

Are those the redbase ones? It says on the copy they're based on Telefunkens. They don't visually look like fat-bottle 6CA7's.

 

[beaubrummels]

AFAIK, it was the JCM900's in the 90's which came with the Sovtek wafer-base 5881's, which aren't really 5881's, but another Russian military variation that withstand higher voltages than 5881's, but that put out less wattage than 6L6's. Again, not much of a NOS tube conossieur, but I've had all Sovtek 5881's, Tung Sol RI (not actual TS's from the 50's) 5881's, and NS Tung Sol 6L6GC's, and they all sound different. The Sovteks have a raspy high-mid emphasis and scooped lower mids. The TS 5881's have a tighter/leaner bottom-end, balanced mids, and some sparkle up top, and the TS 6L6's are darker and fatter.

Yes, I have some NOS TungSol 5881 and they are pretty glorious sounding. They don't remind me of anything; mine are somewhere in between 6L6, EL34 and 6V6 in tone.

Are those the redbase ones? It says on the copy they're based on Telefunkens. They don't visually look like fat-bottle 6CA7's.

They are closer in size to the 6CA7EH than either reissue or original EL34s. Notice how the bottle extends beyond the base.

 

[Rex_Rocker]

Oh, interesting. Are Psvane still making the TAD STR's?

 

[beaubrummels]

Oh, interesting. Are Psvane still making the TAD STR's?

Since they are rebranded, I'm not sure. I'd have to get a Psvane and compare the innards.

But the plate design definitely appears kind of similar to the original Tesla on the right. But it is larger.