Which Yellow Jackets for LSC? Also, amp settings for YJs

[gregrjones]

I'm confused by which THD YJs to buy. The following page lists several types:

http://thetubestore.com/thdproducts.html

Some are what they call "Cathode Bias" and others are labeled as "Power Reducing"

Also, if I want to run 2 EL84s and 2 6v6s, how would I set up the amp's bias switch and power settings?

The Lonestar manual says that if using 6v6's, that I should use the tweed setting and set the bias to 6L6. It also suggests the 4ohm speaker connection. However, would that change if using a combo of 6v6s and EL84s?

 

[Telemaster]

If you change tubes from 6L6 to EL34s all you need to do is change the switch setting and the amp will autobias to the other tubes. As far as YJ's sorry...I stuck with mesa tubes when I changed tubes and the results were great.

 

[Charles Reeder]

Hey:

With the LSC...use the YJSD THD Yellow Jackets.

You can order Tubedepot #20 or #21 hardness JJ-6V6s and use the EL-34 bias setting. None of the current 6V6s I've encountered will actually bias 'warm' enough on the 6L6 bias setting.

But, by using the 6V6s I've recommended (the JJs) at the Tubedepot hardness rating of (20-21), you can get them warm enough without overloading them. DO NOT just throw in any old 6V6s and set the bias to EL-34 mode...unless you have a bias meter to check things out! You could end up exceeding safe levels for the tubes.

Using these recommended 6V6s, you are 'good to go' on either the full or 'spongy' mode.

You can use the 6V6s or the YJs in either pair of sockets...the outer or inner pair. Experiment...you will get a slightly different tone-texture depending on which setup you use.

Have fun! Charles

 

[plan-x]

Whatever he said! Charles is the "Pig whisperer". LSC guru. Hey Charles , where have you been? Good to hear from you again. The board hasn't been the same without you.

 

[gregrjones]

Charles, the only JJ 6v6's that I see on the Tube Depot site are these:

http://store.tubedepot.com/jj-6v6.html

I don't see any option for a "hardness rating"

Also, am I correct that I can also run the YJs with my stock 6L6's? If so, and I wanted to run 50 watts for the lower power option, is the inner tube pair the ticket for the 50 watt setting?

 

[gregrjones]

What if I put 2 YJs in the amp (outer tubes) and leave my two stock 6L6's in the amp? How would I set the bias? Would I bias it for the 6L6's or for the EL34 setting?

Or is this even advisable?

If this is unsafe for the 6L6's because of the bias setting, is it ok as long as I stay out of the 100 watt mode?

 

[Charles Reeder]

Hey Again:

The JJ 6V6s you show ARE the ones to order...so, when you order; you MUST REQUEST that they send you a pair that they have rated and numbered as either 20 or 21.

IF you use a pair of Yellow Jackets and a pair of 6L6s together...then set the amp to the 6L6 bias setting...

HOWEVER...

...if you use a pair of Yellow Jackets and a pair of EL-34s...then set the amp to the EL-34 bias setting.

IF you use a pair of Yellow Jackets matched with EITHER a pair of 6L6s OR a pair of EL-34's...you WILL NOT HEAR MUCH OF A VOLUME DECREASE at the 100 watt setting. A pair of Yellow Jackets and either a pair of 6L6s or a pair ofEL-34s will put out about 70 watts on the 100 watt setting. That is at most about a 1-1/2 decibel volume difference (hardly noticeable!) from what you would hear with 4 6L6s or 4 EL-34s..

By contrast: A pair of Yellow Jackets put out about 20 watts. A pair of 6V6s about 20 watts. Using either one in the 50 watt setting will produce an apparent volume decrease of about 3 decibels...which IS noticeable. Using a mixture of a 6V6-pair and a pair of Yellow-Jackets will produce approximately 40 watts in the 100-watt setting...which once again is approximately 3-decibels less than 100 watts with 6L6s or EL-34s.

The MAIN VOLUME DIFFERENCE obtained by using Yellow-Jackets and 6V6s is the earlier breakup (or tube saturation) obtained. Makes a BIG difference in practical 'Gig-Applications'.

Charles

 

[gregrjones]

Charles, thanks for your insights! If you wouldn't have posted, I don't know if I would have received any answers on this. I love my LSC, but its too powerful of a beast for me even at the 50 W (my amp doesn't have the 10W setting) and Tweed settings for even larger venues with good PAs.

It looks like I need to get 6v6's next.

 

[gregrjones]

I just thought of something. Shouldn't I experience the same volume and wattage drop when using a pair of YJs with either a pair of 6L6s/EL34s or 6v6s in 50 watt mode being that in 50 w mode, the second pair of power tubes aren't in the circuit?

 

[djw]

I just thought of something. Shouldn't I experience the same volume and wattage drop when using a pair of YJs with either a pair of 6L6s/EL34s or 6v6s in 50 watt mode being that in 50 w mode, the second pair of power tubes aren't in the circuit?

Yes, assuming that the YJs are in the outer sockets.

However, keep in mind that the "volume drop" is really, really slight. Not really even a volume drop by most measurable standards. It's more like: you lose a bit of clean headroom, but the amp sounds fuller at a slightly lower volume level. You get earlier breakup... but it's still a loud amp. This is true whether you have the 10/50/100 or the 50/100. 10 watts is still plenty loud.

Don't forget to use the 4ohm speaker jack.

 

[gregrjones]

What about the 4 ohm speaker jack? I know it changes the tone but are you implying that it will drop more power?

 

[gregrjones]

Would I be able to run one Yellow Jacket in one of the two outer sockets and pair the other outer socket with a 6v6 so that I can get the best of both worlds blend of a tone at the lower 50 watt setting?

I would also pair the inner sockets the same way in case I wanted to switch to the 100 W setting....

 

[djw]

What about the 4 ohm speaker jack? I know it changes the tone but are you implying that it will drop more power?

No, it's a better match for the lower-powered tubes' output. Take a look at the back of your amp and notice the "Best for 50-watt setting" note near the 4-ohm jack. This is why they suggest you use the 4ohm + 100 setting when using a quad of 6V6s (and the same applies w/6V6 + YJs). You're actually cutting the output roughly in half, and the output impedance will suddenly mismatch against that 8ohm speaker. The switch to 4ohms compensates for this.

It's a safe mismatch to leave it alone; but it sounds better to switch it. The same goes if you're using a quad of 6L6s or EL34s, and you use the 50w setting on both channels: use the 4ohm output. I do this (currently using 4 6L6s, 50w on both channels), and the 4ohm output makes a big difference. It just sounds warmer and juicier.

 

[djw]

Would I be able to run one Yellow Jacket in one of the two outer sockets and pair the other outer socket with a 6v6 so that I can get the best of both worlds blend of a tone at the lower 50 watt setting?

I would also pair the inner sockets the same way in case I wanted to switch to the 100 W setting....

No!!!! No!!!! No, don't do this!!!! They need to be a matched pair.

 

[JLBoogie]

I have been reading this post with strong interest and trying to understand all said within. It sounds like this might be a solution to my having to choose between selling either my lonestar classic or my lonestar special to continue feeding my amp addiction. If you put the yellowjackets into the classic that uses el84's does it now sound like the special when the 50watt option is selected? Of course this would be if the yellowjackets were put in the outer sockets. Do the el84's have to be to Mesa specs when they are bought or in other words due you need to tell whomever your getting the tubes from you need a certain hardness so as not to harm your amp. Trying to figure out if by using the yellowjackets as needed if it can get me the great tone in my classic as found in the special, then have the option of changing back when I want that great lonestar classic tone I can go ahead and sell my lonestar special and not regret it as much. How many of you are using these yellowjackets now?

 

[Charles Reeder]

Hey:

You don't have to select a certain 'hardness' when using EL-84 tubes with Yellow Jackets...because the Yellow-Jackets themselves contain the current limiting resistors which prevent operation at unsafe voltages...

However...

You can still select EL-84s within the 3-basic 'hardness-ranges' and get earlier or later breakup.

When I first started using Yellow Jackets...I ordered early breakup, medium breakup, and late breakup.

In my experience (for my taste in music) I can get by with just the early and the late breakup pairs if EL-84s.

You can also run the Yellow-Jackets in the EL-34 bias setting to warm things up still more. But do not this unless you are using either: 4-Yellow-Jackets, or a pair of-Yellow Jackets with a pair of JJ 6V6s (at Tubedepot hardness 20 or 21)...or with a pair of EL-34s.

Charles

 

[JLBoogie]

Thanks for the reply Charles, so I assume that when the el84's are ordered you can tell them which breakup you are looking for. If you put four yellowjackets into the sockets you would get 40 watts (class A?) total using the 100 watt option but you can also use 6v6's with the hardness of 20 or 21 and still get 40 watts, is this correct? Have you tried both ways and if you have describe the tonal differences? Have you tried in other Mesa models especially interested in the stiletto duece since it can be so loud also or does it change the tone too much

Thanks

 

[Charles Reeder]

Yes; either 4-Yellow Jackets... OR 2-Yellow-Jackets with 2-JJ 6V6s (Tubedepot 20-21 hardness) will net you approximately 40-watts at the 100-watt setting...or...20 watts at the 50-watt setting...These ARE ONLY APPROXIMATE WATTAGES...but close enough.

As to the sound of these various combinations: The YJs with the EL-84s will definately give you that 'squishier' tone that those tubes are known for. But, using 4-YJs just might be 'too-much-of-a-good-thing'...if you get my drift. I prefer the sound of 2-YJs mixed with 2-6V6s because the 6V6s have a 'crisper' sound which is a bit 'stiffer' and helps hold 'focus' better and aid in individual note definition when used in tandem with the YJs. It's sort of like the 6V6s are the 'bone' and the YJs are the 'muscle'...you need both bone and muscle to really move!
It 's also a fact that 2-YJs and 2-6V6s are CONSIDERABLY CHEAPER than 4-YJs! I always recommend that someone start with a Pair of YJs and a Pair of 6V6s. If you find you still want another pair of YJs then you're not out too much for the pair of 6V6s...on the other hand; if you order and then don't need that 2nd pair of YJs (with EL-84 tubes) you'll be out a considerably larger expense for nothing.

By the way: The reason I recommend the Tubedepot 20 thru 21 hardness JJ 6V6s...is not because no other tube dealers could give a similar match...it's only because I KNOW from taking measurements that their numbers 20-21 will fall within range on the EL-34 bias setting.

And: don't be misled...20 or 40 watts is still plenty loud...I only 'move-up' to the 6L6s when I'm playing both outdoors and un-miked (pretty rare these days).

As to your question about using the Yellow-Jackets and/or 6V6s in a Stiletto Deuce...well I can't help but chuckle...as I'm awaiting delivery of one in the next week or so...and I intend to try those very tubes substitutions in it. So, I'll let everyone know how it worked out ASAP.

Charles

 

[jenks10]

Hi --

Long time lurker/purchaser -- occasional poster here and about Blue Angels...

Just a precautionary Note about Yellow Jackets and the "short" LSC Head.

The short yellow jackets with the Sovtek tubes that come with them won't fit in a "short" head LSC. They are exactly 4 1/2'' tall from the tube socket to the tip of the tube. Turns out it's about 1/8'' too long.

I didn't include the height of the tube socket above the chassis in my measurement, and now I have two brand new short Yellow Jackets I can't use.

FYI -- my LSC "short" head serial number is 000911.

Jenks

 

[Charles Reeder]

Sorry to hear about your problem with the YJs and the short head:

There are a few remedies however:

First: Have you tried the TAD EL-84s? They are shorter in overall length than the JJs, EHs and Sovteks

Also...if you don't mind 'defacing' the onderside of your head cabinet slightly?

Find and measure the exact centers of where the output tubes sit above the bottom of the head. Transfer those measurements to the bottom of the head cabinet. Use an 1-1/4 to 1-1/2 inch wood boring bit and drill through from the underside.

Now you can use the holes to 'dip' the 'tip' of the EL-84 when installing the YJs...

Charles