National NOS Tube Installation Day, a.k.a. No Rice Krispies

[László]

After more than a year, my "First 20" PRS David Grissom 30 Watt amp developed a bit of a "snap, crackle, pop" when the volume was turned up, so I decided to swap out some tubes. Knowing that the crackling was reduced in volume when the Master Volume was reduced gave me a hint that the problem would be in a preamp tube (if it had remained the same when the Master was reduced, I'd have suspected an output tube).

The problem wasn't really microphonic noise or tube squeal, and I guessed that diagnosing it wasn't simply a matter of tapping on the tubes with a chopstick, so I started by pulling the V1, as I bought a few NOS BRIMAR tubes from the 60s or 70s just in case (the "First 20" DG30s are equipped with NOS BRIMAR). When I pulled the V1, I was surprised to find that it was a JJ ECC83S, not a BRIMAR, though the other two 12 AX7s were BRIMARs. The two NOS BRIMARs that were in the spec were in the V3 and V4 positions; that was kind of a surprise! I figured one would be in the V1.

Anyway, I installed one of my NOS BRIMARs in the V1, and closed the amp back up. While the crackle didn't change, the volume was quite a bit lower, although the amp worked fine and there was no additional hum and noise. There was a lot more headroom, but the amp's volume had to be increased to achieve the same volume level. Still, I liked what I was hearing, aside from the crackle in what was obviously a different tube.

I was worried that I might have installed the V1 incorrectly, bent a pin, or something, so I called Jack Gretz, who reassured me that if I'd bent a pin, the amp wouldn't function. Actually, the amp sounded really good with the new tube once the difference in volume was compensated for with the controls, so I decided to leave the V1 in place. The V2 is the 12AT7 reverb driver, so I would leave that in place, too.

Then I opened the amp once again and swapped out the BRIMAR 12 AX7 that came with the amp in the V3 with my NOS BRIMAR replacement). Success! The crackling was gone.

I closed up the amp again, and started playing. With the NOS BRIMAR in the V1 instead of the JJ 803S, it's a different amplifier. Volume difference notwithstanding, the nature of the tone is different, the headroom is different, the feel is even a little different.

It stays much cleaner through nearly all of its preamp gain range, and to get the crunchy thing going to the same degree, it really wants a boost pedal. But the big change is the character of the tone. It's nicer, it's prettier, in a way that I really can't find words for. It's more defined from string to string, with a tighter bottom end that's more piano-like.

Where the JJ is brash, almost brutish, especially in the attack portion of the note, the BRIMAR is sweet. I can't say whether that's because it's NOS, or just a nicer sounding tube, or what. I just like it.

So I'm going to leave it there for a while and see how things go. I'm surprised that it's so much quieter - maybe it's a bad tube, though it's absolutely dead quiet, doesn't hum, and exhibits none of the undesirable qualities of a bad tube - but maybe that's just the way this tube amplifies, and that's why they put in a JJ in the first place.

In any case, it just proves:

1. Tubes sound different from one another; and,

2. Usually when there's an issue with an amp, it's going to be a tube; and,

3. I generally prefer NOS tubes. Not always, but often that's the case.

EDIT:

I should make it clear that I installed tubes from the rear of the amp, obviously, but also turned the amp upside down to make installing the tubes a little easier. So the V1 was on the left, not the right, looking at the amp upside down from the rear.

A friend mentioned to me in a PM that his DG30 had the JJ803 in the V4, phase inverter, position. So I think what might have happened is that the factory installed the JJ803s in V1 in my amp by mistake. Since I like the tone of the amp with the NOS BRIMARs in all the 12AX7 positions, I'm leaving it that way. It's possible, though, that the amp was designed to have the JJ in the V4 (further edit, PRS has confirmed this, so you can safely ignore all of my earlier reviews about this amp, since it's now sounding different! Ha!).

 

[toothace]

Great info Les, thanks for sharing!

 

[László]

What's interesting to me is that not only is the amp less gainy in terms of distortion, it's also more manageable in terms of sheer volume in the room with the NOS tube in the V1 position, even with the master turned to around 3 o'clock, something I could never get away with before the swap.

I just went into the studio and played it again, and the thing sounds great.

I'll also probably learn that I've screwed something up, and you'll all think I'm nuts, (edit: I didn't screw anything up, but you can still think I'm crazy) but it really does sound sweet and it's like getting a new amp!

 

[justmund]

Thanks for sharing Les, been thinking of retubing my HXDA 30, I'm pretty happy with the way it sounds so will prob replace with what's in there (JJ preamp and Winged C power from memory).

 

[László]

Thanks for sharing Les, been thinking of retubing my HXDA 30, I'm pretty happy with the way it sounds so will prob replace with what's in there (JJ preamp and Winged C power from memory).

I'd definitely leave my HXDA as is, too. The only reason I messed with the DG30 was the bad tube, and one thing led to another.

 

[Egads]

What's coincidence! I, too, took pay in the NNOSTI Day celebrations! Mine were with my THD BiValve, with some RCA and Mullards.

 

[László]

What's coincidence! I, too, took pay in the NNOSTI Day celebrations! Mine were with my THD BiValve, with some RCA and Mullards.

I have yet to deploy NOS Mullards in my amps, they're pretty hard to find! But I love RCAs. I installed a couple of RCA preamp tubes in my former Two-Rock and man, it killed. What a sound!

At the time TRs came with NOS Philips 6L6 WGBs, the short bottle output tubes that break up a little faster than big-bottle 6L6s. Great sound.

Unfortunately, I included them in the deal when I sold the amp. I'm going to hunt down a couple NOS.

 

[Chester]

I dont like JJ's 12ax7's in any of my amps except the Matchless Indy. They tame the piercing highs in the Indy, and form a beautiful bloom around the pick attack which I love. Found them to be either too harsh or muddy in my other amps, although they worked reasonably well with Mesa's if I had a Tungsol in V1 to brighten things up

I see Two Rock have supplied Tungsols as stock in my Coral - I love the response, so am not going to roll preamp tubes until one pops. I still have a couple of NOS GE's that could be great in the TR ... I'll have to wait and see

 

[László]

I dont like JJ's 12ax7's in any of my amps except the Matchless Indy. They tame the piercing highs in the Indy, and form a beautiful bloom around the pick attack which I love. Found them to be either too harsh or muddy in my other amps, although they worked reasonably well with Mesa's if I had a Tungsol in V1 to brighten things up

I see Two Rock have supplied Tungsols as stock in my Coral - I love the response, so am not going to roll preamp tubes until one pops. I still have a couple of NOS GE's that could be great in the TR ... I'll have to wait and see

TR installed Tungsols in the Custom Reverb Sig II I had a few years back. They sounded good in that amp. However, my earlier TRs had NOS preamp tubes (and output tubes). I put an NOS GE in my TR Onyx Sig, and it did sound great.

 

[vchizzle]

Yeah tubes can make a big difference in everything you've stated Les. I had put a NOS RCA in v1 and a Bugle Boy in v2 on my Hot Cat 50 and it sounded incredible that way. Don't have that amp anymore, but I kept those tubes. I went through a variety of NOS pre's in that amp and those 2 came out sounding best. I've had less luck finding different pre's I like better in the Archon. It's weird cause I typically hate JJ pre's. I did put a Tung Sol 12ax7 reissue in v1 in and like that, not sure I'd say better, but I like it enough not to take it out right now. I also tried EHX 12ax7 in place of all the JJ's at one point. They aren't a fabulous tube or anything, but I've found them solid, reliable and pretty low noise. I didn't like the change at all really. Ended up putting all the JJ's back in(besides the Tung Sol) and haven't messed around much since then.

NOS tubes tend to make a much bigger difference in amps like the HXDA and DG than something really high gain like the Archon. It's always an interesting experiment. I haven't had the time to mess around much lately and I like the Archon the way it sounds, so why mess with it? I am going to get a set of EL34's the next time I go to record. My intent is to do stereo Archon tracking, maybe with 6L6 on the left and EL34 on the right. I want to do a song that's 100% Archon, even though that goes against my general way of thinking when tracking. Maybe PRS will send me a couple cabs to track with so it'll be a 100% PRS rig? :rofl: There's a lot of different tones and parts on this new song that I'm super excited about. It's pure tonal heaven for me and the best song(or at least our favorite in terms of direction, composition and overall sound) we've written to date.

 

[László]

My intent is to do stereo Archon tracking, maybe with 6L6 on the left and EL34 on the right.

I'd like to share a few thoughts about that with you. I think you'll be wasting a lot of effort thinking you'll hear the subtle difference between different tubes on the same amp in a rock mix.

So I'd like to suggest trying a few different things instead:

1. A different cab and different speakers will make a much more substantial difference.

2. Different microphones would also make a far greater audible difference.

3. If you really want to hear something cool - the caveat being it has to be done well to work - simply mic up your guitar cab in stereo, with two mics. Here's the trick, though: don't make it traditional stereo with matched mics. Instead, try, say, a ribbon on one side, and a dynamic or condenser on the other. Etc.

 

[vchizzle]

Well, I'm not looking for it to sound like a different amp or anything. Every track I record is dual miced with a 57 and 421. In a big thick rock mix, I've found layers and subtle differences to be key. I also play with a different guitar on the doubled track. Throw a 3rd guitar down the middle with P90's or something and you end up with a nice dense mix of layers. I will keep your thoughts in mind.

 

[László]

Well, I'm not looking for it to sound like a different amp or anything. Every track I record is dual miced with a 57 and 421. In a big thick rock mix, I've found layers and subtle differences to be key. I also play with a different guitar on the doubled track. Throw a 3rd guitar down the middle with P90's or something and you end up with a nice dense mix of layers. I will keep your thoughts in mind.

I like the blend of a 421 and a 57 quite a lot, actually, the 421 with its midrange scoop works well with the 57, a very midrangy mic.

I'm into layers, too, it's why I like having a couple of amps around, so I definitely get your point. Whether you'll hear a difference in a layered mix simply with a tube swap... hey, you might. Who am I to say?

The way I like to layer is to dial up the amp settings differently, have some cleaner, some dirtier, maybe even some with a pedal or two. It winds up being a similar concept.

I've also taken to have at least one amp miked up in stereo, not dual mics on the amp, but using a stereo technique, like a Blumlein or spaced pair, etc, as I've found panning techniques to be cool, but you get a different sound going stereo. Then I'll use a mid-side processor to spread the stereo image out and adjust it. Of course, I'm not looking for "sound of the amp in the room" accuracy when doing this, I'm looking for a feeling of spaciousness and hugeness. So that gets blended too.

On a project I'm working on now for one client, I have 6 layers of electric guitar for rhythm, one layer of acoustic guitar miked in stereo, and of course a layer for e. guitar solos.

This isn't a metal or high gain thing, but the clients asked for the sound to build and build, and there are layers of organ, piano, synth pad, strings and orchestral instruments in the track, too. In fact, I'm sure they'd want the sound of a nuclear explosion at the end if I could find room in the mix for one! They've approved the track, but keep asking, "Can we make the ending bigger?"

In addition to the guitars, the violins I and II, the bass, the drums, french horns, double basses and cellos by the end, I have kettle drums. I'm running out of noises! I finally said to the clients, "What are you listening on?" and they said, "A laptop, why?"

So I had them come to the studio. :top:

It's funny, I think an instrumental track inherently lacks the power, both sonically and emotionally, of a track with vocals, even "ooh and ahh" background type vocals, but they won't let me use vocals on this.

It's interesting to fool around with this stuff, you can find lots of ways to go!