NAD - Mesa Boogie DC-3 Head

Awesome. I've had a DC3 combo since they were made new in the mid 90's. It is a great little amp. Amazing clean sounds and a brutal distortion that also does crunchy stuff really well. It is pretty close to the perfect club amp. The switchable EQ is also really a cool feature.

If you open it up, you fill find these things are built like tanks. Steel chassis, chassis mounted tube sockets, chassis mounted pots, thick PCB boards, and big ass transformers. Amazingly well made little amps.

Mine really improved with removal of the mesa 12ax7's and swapping in some tung sol reissue preamp tubes. It really improved the cleans.
 
I ended up selling the DC-3. It was redplating power tubes on a regular basis. I took it to a good amp shop and they could not find anything wrong.

I started reading up and learned Mesa designed the circuit with a higher-than-spec voltage for EL-84s. Mesa would warranty their power tubes in it but even a set of those redplated. As much as I liked the amp's sound, I really need reliability.

Honestly, there was no obvious reason for Mesa to design the amp that way. I think they fixed it in some of their later EL-84 designs but I'm pretty much done with Mesa because of this.
 
USian Pie said:
I ended up selling the DC-3. It was redplating power tubes on a regular basis. I took it to a good amp shop and they could not find anything wrong.

I started reading up and learned Mesa designed the circuit with a higher-than-spec voltage for EL-84s. Mesa would warranty their power tubes in it but even a set of those redplated. As much as I liked the amp's sound, I really need reliability.

Honestly, there was no obvious reason for Mesa to design the amp that way. I think they fixed it in some of their later EL-84 designs but I'm pretty much done with Mesa because of this.
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My Subway Rocket eats tubes, but it's more that they get worn out than redplated. I'm 99% sure in the 20 years since these amps were produced, Mesa has stopped that practice.
 
My dc3 is pretty hard on power tubes. After about a year or so of regular use they start to get all volume swelling and sound crappy. Luckily they are pretty cheap tubes. I never had any redplating on mine.
 
Help!I'maRock! said:
My Subway Rocket eats tubes, but it's more that they get worn out than redplated. I'm 99% sure in the 20 years since these amps were produced, Mesa has stopped that practice.
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Sure. My gripe is I could never understand a reason for them to even design it that way. I love the sound of EL-84s, There are many companies making amps that don't eat them.

I don't really need the EQ options and gain that come with a Boogie. On the other hand, I love their overall construction and cleverness. This just seems like something that should have never been allowed into production in the first place. There's a fix for it on the internet that involves soldering in a higher-value resistor. It's not like it was hard to stay within spec.

If I were the suspicious type, I might think they did it to keep people buying Mesa tubes.
 
All mesa el84 amps run the tubes ridiculously hot. My express puts 400v on the plates and was dissipating 15w with stock "mesa" tubes. Mesa tech support said this is normal.

I modded the bias to run them cooler, and bought the coldest set of jj's eurotubes offers. Sounds great and the tubes last.
 
wagdog said:
All mesa el84 amps run the tubes ridiculously hot. My express puts 400v on the plates and was dissipating 15w with stock "mesa" tubes. Mesa tech support said this is normal.

I modded the bias to run them cooler, and bought the coldest set of jj's eurotubes offers. Sounds great and the tubes last.
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Maybe that’s why I’ve never had a tube issue with my Mesas. I’ve always had 6L6s or EL34s.
 
Chad said:
Maybe that’s why I’ve never had a tube issue with my Mesas. I’ve always had 6L6s or EL34s.
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I had the express 5:50 (6L6) for a while, ran the tubes at a "normal" bias.

When I was going through Mesa branded el84 tubes in my express, it was still under warranty and I was in contact with Mesa often. They sent me 4 sets of el84s to replace the 2 sets I bought that redplated within days. The matching on them was awful, at least 5ma difference. One boxed set was 7ma. The jj tubes I get from eurotubes are within 2ma of each other. One set I bought was an exact match. Between the cold tubes and modding the bias circuit, I'm good to go.

I don't know why Mesa continues to cling to the notion that an adjustable fixed bias is a bad thing.
 
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