A Little Tube Rolling Over The Weekend, And My DG30 Is Even Sweeter!

László

Too Many Notes
Joined
Apr 26, 2012
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Location
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Even though I've been playing (and messing around with) tube amps since 1966, I still have to work myself up to unscrewing the amp's back cover, and pulling out tubes. I've never broken a tube or even bent a pin in all that time, but I still have it in my mind that I'm going to pull a tube, make a mistake, and break the world!

This despite the fact that it's as easy as changing a light bulb.

When last we visited the innards of the DG30, I had replaced a bad V3 with a spare NOS BRIMAR CV4004 box plate, and swapped out the V1 for another NOS Brimar 12AX7 that was a little lower gain thinking I'd make the amp a bit cleaner. There was also an NOS BRIMAR CV4004 (these are also 12 AX7s with military labels) in the V4 phase inverter position.

Saturday I decided that I wanted to return some of the original gain structure to the amp, without making it over the top. First I swapped in a different BRIMAR for the V1. It restored the gain, but it was a bad one, it hummed. Well, it's a 50 year old tube, what did I expect? Some go bad I guess.

Fortunately I had a spare JJECC83s, so I put that in the phase inverter position (V4) and put the BRIMAR that was in the V4 into the V1.

This put the amp into the configuration this model shipped from the factory, the only difference being that I had some NOS BRIMARs from my own stash in the amp. In any case, I lucked out with the right tubes in the right spots, because the amp is running dead quiet, the gain structure gets that "edge of breakup" clean tone a little more easily, and the amp sounds even more like the amp Grissom recorded on How It Feels To Fly.

For some reason these little tweaks - finding just the right individual tube for each position - have given me an amp that can truly give my beloved HXDA a real run for the money as a #1 amp.

While I've always really loved the DG, I've also usually turned instinctively to the HXDA when the chips were on the line for a solo, etc. Now, I think I'd be just as inclined to track both amps at once, and use the track that sits better in the mix (I have splitter boxes that let me do that without adding any hum or noise). Or maybe blend them.

When you have a great amp, and think "great, but I'd like it to do this one tiny thing in a different way," it is definitely worth the small amount of effort it takes to swap some tubes and see if things can't be further tweaked to one's taste.

Nowadays we aren't very patient with our gear. If it's not living the dream from Moment One, our tendency is to put it up for sale on the web, and fire another salvo in the direction of our dealer for a new thing. Without commenting on the time and expense that kind of thing involves, it certainly makes sense to get a few different preamp and output tubes in one's collection, and try them out in the various positions.

We have the power to affect our amps' tone, and too often we don't realize what's possible. :)
 
Great thread Les! I tend to be all about modding guitars to get then where I want them, but never think to do this with amps....
 
Great thread Les! I tend to be all about modding guitars to get then where I want them, but never think to do this with amps....

Thanks Dane! The nice thing about simple stuff like tube swapping is that it's so darn easy to do, and it's instantly reversible.

The biggest changes happen in the way different tubes respond to being overdriven, but there are often changes in the amp's noise floor, and even gain volume as the tube brands all have different sensitivity and noise specs, and of course most tubes' tolerances vary from the spec a little bit.

Even JJ's new preamp tubes come in different flavors with different specs, if you look, for example, at their ECC803s vs their ECC83s. I mention this because PRS uses JJs in the preamp section of most of their amps.

Of course, the biggest change comes with different speakers...my back has gotten to the point where that's become a little bit difficult for me, but I've been known to do it. Currently eyeing some of the new Celestion Alnico Creams...
 
Thanks Dane! The nice thing about simple stuff like tube swapping is that it's so darn easy to do, and it's instantly reversible.

The biggest changes happen in the way different tubes respond to being overdriven, but there are often changes in the amp's noise floor, and even gain volume as the tube brands all have different sensitivity and noise specs, and of course most tubes' tolerances vary from the spec a little bit.

+1

And to state the obvious, so much depends on the circuit design, and how the designer intended the sum of the all parts to interact. Chinese 12XA7's may sound brittle and thin in one circuit, but truely exellent in another that was designed around them

My Carol Ann is a classic example - V1 went micro, so I replaced it with a balanced Tungsol. The response was boxy and middy (put me in mind of a Mesa Roadster I owned when my world was all things Mesa), which I could not dial out. Replaced it with a Chinese TAD and BANG - normal service is resumed. On the other hand, my Two Rock Coral has been designed around Russian Tungsols, and sounds c**p with Chinese glass in V1 &2 ..

With 5 heads in my current arsenal, and many that have been and gone, my spares stash is extensive enough to roll and trial 'till the whisky runs dry. Some have proven to be a great improvement, but for others, I have learned to stick with originals. Now, off to get some more Chinese glass ..
 
+1

And to state the obvious, so much depends on the circuit design, and how the designer intended the sum of the all parts to interact. Chinese 12XA7's may sound brittle and thin in one circuit, but truely exellent in another that was designed around them

My Carol Ann is a classic example - V1 went micro, so I replaced it with a balanced Tungsol. The response was boxy and middy (put me in mind of a Mesa Roadster I owned when my world was all things Mesa), which I could not dial out. Replaced it with a Chinese TAD and BANG - normal service is resumed. On the other hand, my Two Rock Coral has been designed around Russian Tungsols, and sounds c**p with Chinese glass in V1 &2 ..

With 5 heads in my current arsenal, and many that have been and gone, my spares stash is extensive enough to roll and trial 'till the whisky runs dry. Some have proven to be a great improvement, but for others, I have learned to stick with originals. Now, off to get some more Chinese glass ..

Funny that you mentioned the Chinese tubes. One of my mid-2000s TR Onyx Sigs came with NOS 80s Chinese preamp tubes, and 70s JAN Phillips output tubes. That combination, in that amp, sounded wonderful. When I replaced the preamp tubes with some Telefunkens, I didn't like it as much and put the Chinese preamp tubes back in. Eventually a NOS RCA wound up in V1, but it wasn't an improvement, as much as a different vibe. When I sold the amp, I left the RCA in and kept the Chinese tube. I still have it.

BTW, my world was all things Mesa for about a decade. I still like their amps, even though I currently don't have one. They do a thing, and it's a pretty good thing when you need that thing. ;)
 
BTW, my world was all things Mesa for about a decade. I still like their amps, even though I currently don't have one. They do a thing, and it's a pretty good thing when you need that thing. ;)

Great amps - great builder. Loved them for over 20 years. I was lucky enough to own a Tri/2:90, LSC, Roadster and MKV ... my playing style changed following that "elusive sound in my head" nemesis, which is the only reason I don't have any now
 
Great amps - great builder. Loved them for over 20 years. I was lucky enough to own a Tri/2:90, LSC, Roadster and MKV ... my playing style changed following that "elusive sound in my head" nemesis, which is the only reason I don't have any now

In many ways, they're the working man's Two-Rock, there's a similar thing at work there with the cascading gains, etc.

My first one was a Tremoverb, but at one point I also had a Maverick, a Subway Rocket, a Blue Angel, a Bass 400+, a Stiletto and later a Mark V in the studio. I liked every one of them, but eventually got into some of the handwired amp offerings and kind of got stuck there, especially after getting the HXDA and DG30.

But I still breathe hard whenever I see a Mark V, it's a fun amp.
 
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