Winger =C= SED 6L6-too much bass & not enough gain- ma 18.9

[Adambomb]

So let me tell ya I was really looking forward to rockin the SED Winged =C= 6L6's in the Mark V yesterday. I LOVED what they did to my Dual Recto- tightened the bottom end, gain was alot smoother, highs were very sweet and not harsh.

Well maybe it is just the batch of Winged C's I got cause in the Mark V it isnt that great. The bass was WAY too much and had to roll off the bass knob completely on Ch 3. The highs were pretty smooth. But the mids arent as gainy as the stock 6L6's.

I was only out $40 since I already had 3 new SED 6L6's and just called Doug got another one that matched. Maybe the tubes don't have enough plate current. the Plate current (ma) is 18.9, 18.9, 18.8, 18.7 on all 4 tubes. If this low for Mesa amps? I know that Mesa amps are biased pretty cold and told them before I ordered that they were going in a Mesa. So isn't that a little low plate current of 18.9 for tubes in a Mesa?

PS: I posted this topic in the Mark V forum too.

 

[crane]

Assuming the plate voltage is around 500V :
500 x 0.0189 = 9.45 W
9.45/30 = 31%
They are biased super cold ! (they should be between 50% and 70% for an optimal sound)

So of course at this setting you're not getting a nice sound.
Ask a tech about a bias mod (don't know how to do it on a simulclass amp) or get some hotter tube.

 

[Adambomb]

Well that suchs. So want amp would these tubes be suitable for? Doug from Doug's Tubes told me they were medium gain and would work great in any Mesa amp. And they don't glow that much either. The stock Mesa tubes glow 5 times brighter but I know the glow has nothing to do with nothing. Is there nothing I can do for the tubes to get them to run hotter without messing with bias on the amp? Probably not.

 

[crane]

One thing I don't know with the Mark V is if the bias change with the "power output mode".
How much current did the stock tubes draw ?

 

[Adambomb]

One thing I don't know with the Mark V is if the bias change with the "power output mode".
How much current did the stock tubes draw ?

I dont know how much current the stock tubes draw. I dont have any equipment to measure this. I'm not the most technical person about tubes and amps, I just know the basics. I knew that the numbers on the SED 6L6's looked way to low though. Since they are very cold tubes, what amp would they be suitable for then if any amp?

 

[Adambomb]

I got an email from Doug and he said this about my SED 6L6's and I truly trust this guy, he's been great:

Doug's Tubes: 18ma is not at all a cold bias tube and right in line with the range of tubes Mesa sells through their store, their color coding corresponds to Groove Tubes 3 through 7. I had a set of Mesa tubes here 2 weeks ago that a local customer was trying to match up with Sovtek WXT+'s, and they were 18ma. It's also in the range of idle current tubes Mesa purchases from Ruby and relabels as the STR-440.

 

[crane]

For me it is a cold bias. Way much cooler than in other amps (Marshall, peavey, Fender, ....).
Take a look at this articles.

http://www.aikenamps.com/Biasing.html

http://www.aikenamps.com/Why70percent.html

 

[swbo101]

I've been using SED =C= for about a year now in my Mark IV. I switch between all 6L6's and 6L6, EL-34 combo. I buy them from tubedepot.com. They don't sound the way you've described how yours sound in the Mark V. I don't know the ma rating in mine, but the rating number on my 6L6's are "21" and they rock. Love them. When purchasing from Tube Depot I mentioned they were for a Mark IV and that a middle rated tube was needed.

Just my .02

 

[stokes]

Just because a supplier says they are "18.7ma's" doesnt mean that is what they will draw in your amp.That is what they draw in whatever he used to rate them.It is not unusual to see tubes drawing that range in a Mesa amp,but that is indeed very low,even for a Mesa.But who knows,in your amp they may be drawing 10ma's.Unless you check them in the amp,you cant be sure.The only way to use those tubes in your amp,to your satisfaction,would be to check and adjust the bias.They will work safely,but not necessarilly optimal.I have seen Mesa tubes of the same rating vary by as much as 15ma's,but always well below the optimal 70%

 

[212Mavguy]

+1.

Plus:

When your amp goes off warranty get the bias pot mod done.

Period.

'Til then, get tubes rated towards the hotter, higher current draw of the available and warranty-friendly spectrum.

"Brightness of heater glow" means nothing between tubes of similar types but of different builders.

 

[Tommy_G]

I would doubt if its the tubes by themselves....its how the tubes are voiced or revoiced through the power amp negative feedback thats the issue here.

In the way of explanation:

You are comparing expectations for a Mark V vs. a Recto.

Unless Mesa made a major adaptation away from Mark series power amp configurations, the Mark V probably has a much different negative feedback configuration in the power amp than the Recto.

I cannot bare to use 6L6s of any kind in my Heartbreaker. The Heartbreaker borrows heavily from the Mark series, including in its power amp section. Wayyy too much bass. The bass and low mids are so powerful I feel like I have shell shock when Ièm done with them. The voicing of El34s (reduced bass and low mid response) are awesome in the Heartbreaker.

My Nomad, which carries many characteristics of the rectifier series, including a fixed bass cut in the NFB loop sounds best with 6L6s, because the bass cut in the NFB works to revoice the 6L6s into more neutral territory.

If you want to stick with 6L6s for your Mk V, I think youll have to find lesser tubes than the broad spectrum winged C 6L6s, and start dialling wayyyy back on your bass, probably best through cutting the bass on the graphic eq, or find speakers that are less aggressive in the bass frequencies.

 

[Adambomb]

I would doubt if its the tubes by themselves....its how the tubes are voiced or revoiced through the power amp negative feedback thats the issue here.

In the way of explanation:

You are comparing expectations for a Mark V vs. a Recto.

Unless Mesa made a major adaptation away from Mark series power amp configurations, the Mark V probably has a much different negative feedback configuration in the power amp than the Recto.

I cannot bare to use 6L6s of any kind in my Heartbreaker. The Heartbreaker borrows heavily from the Mark series, including in its power amp section. Wayyy too much bass. The bass and low mids are so powerful I feel like I have shell shock when Ièm done with them. The voicing of El34s (reduced bass and low mid response) are awesome in the Heartbreaker.

My Nomad, which carries many characteristics of the rectifier series, including a fixed bass cut in the NFB loop sounds best with 6L6s, because the bass cut in the NFB works to revoice the 6L6s into more neutral territory.

If you want to stick with 6L6s for your Mk V, I think youll have to find lesser tubes than the broad spectrum winged C 6L6s, and start dialling wayyyy back on your bass, probably best through cutting the bass on the graphic eq, or find speakers that are less aggressive in the bass frequencies.

Sent the tubes back to Doug a couple weeks ago and that was the problem. And I did have my bass ALL the way rolled off. Thanks for your input though.

 

[Jackie]

I wanted to post early in this thread but since it wasn't my amp, I remained silent because I didn't want to write anything were it not useful. But now I can't help myself: I KNEW the =C='s wouldn't dissapoint

 

[Adambomb]

I wanted to post early in this thread but since it wasn't my amp, I remained silent because I didn't want to write anything were it not useful. But now I can't help myself: I KNEW the =C='s wouldn't dissapoint

Actually the batch I got did dissapointed. Did you not ready the whole thread? But I LOVE the SED's don't get me wrong they rock. Did a AB comparison with some SED 6L6's and some Ruby 6L6's (same as Mesa tubes), and they were almost the same. SED's ***** been a little soother but not much. I'm sticking with Rubys from now on, or stock Mesa tubes, it's all the same thing. I can't justify paying double for the SED's. Spending more time swappin preamp tubes for tone is where it's at.

 

[Jackie]

I did read the whole thread, I wanted to imply that I knew working SEDs don't disappoint :mrgreen:

I agree with swapping preamp tubes. I'm doing the same for my TriAxis right now