One more question on taking 2 tubes out to lower a DR to 50w

[fleeced]

Dual Rectifier: (3 channel)

OK - I'm still playing with effects loop (on / off ... on and patched with a jumper cable etc.) ... but after gigging with the amp for over a year ... I finally read the thing about removing two tubes to cut the amp to 50w.

I've done this and get much more saturation and warmth at lower volumes which is great.

The book says to remove one of the pre amp tubes along with two of the 6L6's ... but I am sure the sound has more depth with both of the pre-amp tubes left in. (Maybe wrong here but it seems to sound "thinner" with just one)

Can anyone out there advise if this is going to cause any damage ?

What effect does removing one of the tubes have? - is it my imagination that the sound is different?

Also any recommendations on changing the pre amp tubes to another type and what effect do the other options have on the sound?

Thanks in advance

 

[mikey383]

Whoa dude. The manual didn't say to pull PREAMP tubes, but RECTIFIER tubes.

Pull one of the 5u4s...the big ones to the right of the 6L6s. Doesn't matter which one...they're wired in parallel. But you only need to do that if you are using the tube rectifier and want the sag. There's no harm in leaving them both in, you'll just get less sag. If you're using diode rectifiers then you won't need to pull either one of them.

It's no wonder you think it sounds different if you're pulling a preamp tube.

 

[fleeced]

My mistake in terminology! ! ...

I did pull the right one.

So do I get less sag with leaving the two in?

Maybe somewhere between the tube and silicone diode setting?

thanks for your reply ...

 

[stephen sawall]

I kind of like a Tung sol in V1. It kind of smooths out the sound.
As a other voice.

 

[mikey383]

My mistake in terminology! ! ...

I did pull the right one.

So do I get less sag with leaving the two in?

Maybe somewhere between the tube and silicone diode setting?

thanks for your reply ...

Ok then. That first post had me wondering how the amp was even getting sound at all. So you do have the right tube out.

Yes, you'll get less sag with both rectifiers in the amp. Not as stiff as diodes, but not as saggy as it could get. I'd say it equates to using GZ34s in the rectifier spot.

 

[fleeced]

Ok then. That first post had me wondering how the amp was even getting sound at all. So you do have the right tube out.

Yes, you'll get less sag with both rectifiers in the amp. Not as stiff as diodes, but not as saggy as it could get. I'd say it equates to using GZ34s in the rectifier spot.

Thanks man - much appreciated.

Only problem now is that I seem to be developing an obsession with reading everything there is to read about the different tubes out there ... but I guess the only way to find out the differences that they make is to buy 'em and try 'em... Which could start to prove an expensive occupation !

 

[Noonoo]

In addition, I would like to know how doing this compares to just using an attenuator.

 

[mikey383]

In addition, I would like to know how doing this compares to just using an attenuator.

Using an attenuator can get you into major power amp distortion at acceptable volume levels.

Pulling tubes just basically allows the amp to breakup at lower settings. The volume change isn't as drastic as using an attenuator, and the tone changes somewhat. 50 watts is still plenty loud.

 

[Fixxer6671]

Call MESA, but you can.

1. Pull the 2 outer or 2 inner tubes
2. pull one rectifier tube

but CALL MESA

 

[fleeced]

I'm running the amp with two power tubes and two rectifier tubes - getting a great tone at slightly lower volumes than at 100w.

It just enables me to get some lovely warmth in the tube break up at a volume that doesn't threaten to shatter windows and ear drums!

Also it seems to have made the clean channel sound more real and less "firey".... As at normal volumes it used to seemed too dynamic, and I feel that driving it at a higher percentage of capacity seems to have flattened off some of the volume peaks. (In a good way!)

Gonna play with some different tubes as well to see what difference they make .... got some Tung Sol's to try in the pre amp ... some JJ's to try in the power tubes and a couple of new Mesa 6L6's as well just to see if there's any deterioration in the ones I'm currently using.

Never tried an attenuator but have heard that they suck tone out as they don't respond to the amp's output like speakers do ... ??? .... Anyone got any experience with these? out of all of them THD seem to get good reviews ? ? ?

Thanks for the advice guys

 

[fishyfishfish]

I just started running my dual with two power tubes and I cant really tell any difference at low to medium volumes, little more "50 wattish" I like it.
As for attenuators, I use a Z Air Brake for about two years with my LSC with good results in tone. The down side is I went through power tubes like crazy, and it was just one more thing to haul around and mess with. I also used the THD which is pretty good as well. I didn't notice that much of a difference when I used them on my Dual. More touch sensitivity and a little more thump and compression, but at the expense of my tubes and components.Finally, I pulled the plug and just went back to normal. Just my thoughts.

 

[fleeced]

I just started running my dual with two power tubes and I cant really tell any difference at low to medium volumes, little more "50 wattish" I like it.
As for attenuators, I use a Z Air Brake for about two years with my LSC with good results in tone. The down side is I went through power tubes like crazy, and it was just one more thing to haul around and mess with. I also used the THD which is pretty good as well. I didn't notice that much of a difference when I used them on my Dual. More touch sensitivity and a little more thump and compression, but at the expense of my tubes and components.Finally, I pulled the plug and just went back to normal. Just my thoughts.

Thanks for that. Not sure I like the sound of the amp eating tubes though! I've also heard the THD is pretty good, - seemingly OK on tone as long as you don't need too much attenuation. I've also been recommended the Weber Mass (or Mass Lite) - which use a speaker cone as well as resistors to attenuate, supposedly giving a more natural response to the amp's output. Sounds good in principle.

You're right about one more thing to haul around though... I'm really not sure whether to go for yet another bit of kit ... unless there's a real noticable improvement to the sound. - Guess I need to try one !!!

 

[fishyfishfish]

Let me clarify the tube thing: I was being kind of a dolt and running my amps where I thought they sounded good at the volume that was right, all the time. I think that Attenuators are good tools when used wisely, to knock a few db off the top, not to make my 100 watt stadium monster a bedroom practice amp that I can use while I watch TV. Right now I use a 1x12 for miked gigs, and a 2x12 for the bigger stuff and although it took me a while to get used to, I can get the volume I want without an attenuator and get things sounding pretty good.

 

[fleeced]

Round in circles and back to sqaure one ....

Rig sounded fine for practising ... but when I rehearsed the sound with just two 6L6's was too "thin". The clean was Ok, but the overdriven sounds were too harsh and lacked the depth and warmth with 4 tubes.

So I replaced tubes ... am back to "spongy" ... and am back in tone heaven!

Crazy ... but in the search for something better I lost the tone I had in the first place.

So now I'm back to 100w and looking to buy an attenuator for practising! ...I practice pretty loud anyway so will only be knocking a bit off the top ... Not sure I now need an attenuator for gigs. Who knows ....

I've also taken the Tung Sol out of V1 (I prefer the Boogie tube) ... taken the JJ's out of the 6L6 power tubes .... (I prefer the Boogie Tubes!) ... My Dual Rec now sounds like a Dual Rec again ... I've knocked some gain out of the clean channel, - it sounds great ... lowered the volume on the preamps on all channels, which allows me to increase the master volume ... and I'm enjoying the amp loads again.

Rehearsal tonight the band gave an unprompted compliment on the "sweet sounds" coming out of the rig ....

Just goes to show ... !

 

[stephen sawall]

That was pretty much what I did ....
Go figure.
I have never heard a amp that sounded better with tubes pulled.
But is a good thing to know how to do if you find yourself in a spot.