Yellow Jackets

[metalchurch]

I think that there was a thread or topic about this before, so if there was, sorry.
http://www.amptone.com/thdyellowjackets.htm
http://www.thdelectronics.com/product_p ... acket.html

I was reading up on them tonight, and I did not realize exactly how great these things are!
I was trying to figure out other ways beside an attenuator to bring down the wattage, and I think these are the ticket here!

They say that I can take a 100w Marshall remove all of the stock power tubes and use (2) YellowJackets to make it into a 20w machine!
Use (4) YJ's and it will be 40w
Use (2) YJ's and (2) stock tubes (not sure what that would be? (80w???)

I never realized that these are simply a drop in and play type of mod, requiring no re-biasing!

It essentiall turns a Class A/B into a cathode based Class A, which is very cool!
They run about $60.00 a piece with an EL84 tube included. Not sure what brand or if you have a choice, when ordering?

I think that Orangekick, and perhaps VENTgtr have tried these, well atleast I remember one of them talking about it.

Could one of you guys refresh this topic with your thoughts and experiences?

I have more questions, but this is good for now.
Thanks alot!

[orangekick]

I have a pair of them and I really like running them in a 100 watt amp with two regular power tubes in addition. I find that the overall sound comes down a little bit and that the break up happens a little earlier. I have run the pair of Yellow Jackets in a 50 watt amp as well. That brings the wattage down to 15 watts. It's still loud, but it's the kind of loud that you can stand in front of with the amp cranked.

You can just drop them in your amp with no changes to anything. If you look around, you can find some used on occasion.

[metalchurch]

Yeah Orange, that's exactly what I'm talking about there! Getting the watts down to a liveable level, yet it's still loud.

Couple of questions:
#1 What brand of EL84's did your YJ's come with?
#2 What's a good brand of '84's?

#3 How long have you been using these?
#4 Have you had any problems with these at all?
#5 What amp do you have them in?

YJ's run hotter, so do they have a shorter life span than something originally designed for EL84's?

Thanks

[lonewolf]

Sell all your stuff and get a nice EL84 class A powered amp.

[metalchurch]

Sell all your stuff and get a nice EL84 class A powered amp.

Jeff, I want a Marshall EL84 20/20 so bad I can taste it right now!
I must have bumped my head, I dont know whats gotten into me lately?!
Gonna be 30 yrs old on Feb 5th, so maybe it's an early mid-life crisis, or I'm getting ALD?

Jeff or anyone else, do you guys know of another rackmount tube 20w poweramp that would be like the equivalent to the 20/20?

[lonewolf]

Mesa makes one.

http://www.mesaboogie.com/Product_Info/ ... tereo.html

I have had both the Mesa and the Marshall. They are both great sounding. The Mesa has a more dynamic, open musical sound and the Marshall had more of a, well, Marshall sound and the deep switch makes it a little better for metal; however, you could probably use the 9-band EQ in the MP-2 to get the same sound out of the Mesa.

The Marshall has serious overheating problems and I would never trust one on stage again (how 'bout it JP, at Magoo's back in 2000). The tubes are on the inside and there is not nearly enough ventilation--even if you waste a rack space above it. The Mesa's tubes are on the outside, rear, and can be changed without removing it from the rack. You can mount the Mesa in a rack and not waste any spaces ventilating it. The Mesa would hands down be a better choice for the ADA MP2.

They are both the same size and will just fit into a Gator FX rack, with about an inch sticking out the back. (it clears the covers by about an inch)

[metalchurch]

I've heard about the heat problems with the Marshall online. Some guys said the same thing as you regarding the tube placement design and the inherent overheating problem.

What problem arose when your 20/20 overheated?

I sold my ADA MP-2 a while ago, but I want to get another, or an MP-1 with the 3TM.
The EQ section of the Mp-2 was great because it had a 3 band graphic eq, plus I believe either a 7 or 9 band parametric EQ.

Do you think the top cover of the Marshall could be modded for better ventilation? Would there be enough room for another fan? Or perhaps a rear loaded rackmounted fan would work.

Thanks for the insight Jeff, it's much apreciated

[metalchurch]

Jeff, I saw that the Mesa has a fixed bias. Does the Marshall have a fixed bias as well?

[orangekick]

Jeff, I saw that the Mesa has a fixed bias. Does the Marshall have a fixed bias as well?

Mesa makes their amps with no bias adjustment. This is a bit confusing. All Marshalls need to be rebiased when you replace power tubes. Marshalls are what is called fixed bias. Fixed bias means that the bias point of the amp is fixed in one spot and should be adjusted for each set of tubes.

Some amps are cathode biased and they do not need to be adjusted when you replace the power tubes. I have a Budda Stringmaster that is cathode biased and it never needs any adjustments when you replace the power tubes. I would use the Budda for everything, but 30 watts just isn't enough for me all the time.

[orangekick]

Yeah Orange, that's exactly what I'm talking about there! Getting the watts down to a liveable level, yet it's still loud.

Couple of questions:
#1 What brand of EL84's did your YJ's come with?
#2 What's a good brand of '84's?

#3 How long have you been using these?
#4 Have you had any problems with these at all?
#5 What amp do you have them in?

YJ's run hotter, so do they have a shorter life span than something originally designed for EL84's?

Thanks

The Yellow Jackets that I have came with JJ EL84's. I prefer Electro Harmonix EL84's myself. They're just a little more present in the mids and the bottom end is a little better. I have had the YJ's for about 6 months and our other guitarist had them before that. I have had zero issues with them at all. I was running them in my Dual Rectifier. That was actually the best tone that I have ever had out of a Dual Rec. I was running 2 SED 6L6's and the 2 YJ's and the tone was awesome.

I think you'll find that EL84's tend to run hot no matter what. They still last quite a while. They're also pretty cheap as far as power tubes go, so I wouldn't sweat it at all.

Just keep in mind that your overall tone will be a little different. The bottom end on EL84's is really different from 6L6's and EL34's.

I could just mail you my pair to try out if you want. We're recording right now and not playing any shows until that is done. I wasn't planning on using the YJ's during the recording.

[metalchurch]

No kidding?!
That would be very cool of you man!
I know that I'm gonna like them from what I've read and what you guys all say about them.

The only problem that I foresee is that they are alot taller than the 5881's that are in my 9200 now.
But I can probably get away with either removing or adding spacers to the top cover of the '92 and leave a 1 space gap in my rack.

I'll pm you my full name and addy.
Thanks bro!

edit:
Thanks for answering everyone of my questions too.

[lonewolf]

I've heard about the heat problems with the Marshall online. Some guys said the same thing as you regarding the tube placement design and the inherent overheating problem.

What problem arose when your 20/20 overheated?

We (Penetrator) were playing at Magoo's and JP was there to cover us and right in the middle of a set it just overheated and shut off. The band played 3-piece while I yanked it out of the rack and sat down with JP to remove the cover and check it out. I left the cover off and put it on top of the rack and it worked OK after it cooled off. I never used it again live and sold it on eBay a little later.

Do you think the top cover of the Marshall could be modded for better ventilation? Would there be enough room for another fan? Or perhaps a rear loaded rackmounted fan would work.

No. It is a fundamentally flawed enclosure design. On one-rack-space enclosures that generate a lot of heat inside, you need the air flow from front to back. If you look at the back of the Marshall, there are no vents. It has a front-to-top/bottom air flow and grossly insufficient venting.

Mesa got around this by putting the tubes on the outside and also doubling up on the venting. Never had a problem with mine. Both amps are excellent sounding for hi-gain, but the Mesa 2020 is as good as it gets for clean tones.

[metalchurch]

That makes sense to me Jeff. Thanks again for your help and insight on this and for answering my questions.
You guys rock!