HDRX 20 Tubes

B

bigben55

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Joined
Sep 11, 2023
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Has anyone done any successful tube upgrading? If so, what sounded best? As a rule of thumb, on modern amps, I usually don't go all NOS tube crazy, as modern amps were mostly designed around using new production tubes, while, ie a 1966 Super Reverb was designed around hosing RCA and Sylvania tubes what back then.

But preamp tubes are always up for upgrading. Any winners? I can't say, historically, that I've lived those JJ ECC83S tubes. And I do love JJ tubes. I think that one us the worst of their preamp tube offerings.
 
I use NOS Mullard preamp tubes in my HXDA, and it's conceptually a similar amp to the HDRX.

After all, both are based on a vintage Marshall, and those were the tubes to use with a Plexi.

Sounds beyond wonderful with them, but I also installed Siemens EL34s - those were suggested by Doug Sewell when I met him at PRS Experience after buying the amp. The Siemens sound a little leaner than the Winged C the amp came with, and I like it better with them.

My only caveat would be that my taste might be different from yours - I think the JJ ECC83S is a pretty good modern tube in the right amp.
 
If memory serves, I currently have the following:
V1: JJ e83cc
V2: JJ ecc803s
V3: NOS RCA 12ax7 (long grey plate)
Power: NP Tung Sol 5881

For a while I had a short plate NOS Mullard in v1, it sounded great, but with the e83cc it sounds and feels almost indistinguishable, so I left the JJ in just to keep the hours down on the Mullard.

I’ve really grown to dislike the ubiquitous JJ ecc83s in the PRS amps, they just push way too much gain and blow things up too early in the circuit. Other amps are more forgiving of them, as you said, being made for modern tubes and maybe even designed around that tube because it’s so popular.

I’ve also found the phase inverter position of PRS amps (and reverb driver, on those that have it) to play best with NOS tubes. Not specifically for tone, but surprising effects on noise floor and microphonics. I’d put an ecc803s there if you want to avoid the spend on NOS.

The JJ e83cc and NP Mullard ecc83 are tied for being my favorite new production 12ax7, with the JJ ecc803 being close behind. I usually choose between the first two based on how much gain I want, Mullard having the least. But there’s also the country of origin thing with Mullard right now.

Power tubes, I did get an NOS set of Tung Sol 5881’s, and they sounded good, but again not good enough to warrant putting hours on them over a set of spare NP Tung Sol’s I had. But, again, country of origin.
 
I have experience with the JJ E83CC AND ECC803S, like them both, prefer them both to the ECC83's. I was planning on getting another one of each for v1, v2. On other amps, I've used Sovtek 12AX7LPS for phase inverter slots, was gonna order one for the PRS.

I'd assume the Tung Sol 5881s are probably the best of the modern offerings. My experience with TS 6V6 tubes has been, sound great, but don't last long. I currently have some Sovtek 5881s in the tube box which I'll try next. And I'll order some JJ 5881s. Anyone able to comment on those?
 
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I haven't changed a thing because it sounds so good as is.

But all of my old Gibsons and Fenders from the 50's and 50's have NOS RCA, Mullard, etc. from the 50's and 60's in them.

There's hardly any tubes in the HDRX 20!

Two power tubes and three preamp amp tubes...right?

Solid state rectifier...not a tube.

Been playing a lot of bass through mine, btw.

Sounds killer. Just have to be careful and keep the volume down playing through guitar speakers.
 
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I bought my amp new, back in May, so the current 5881's should have plenty of months left on them. I run 5881's in another amp as well, only have the 1 backup set, so I could use another.

I used to have a Dr Z Z28 combo. In that amp, biased at 65% dissapation, the Tung Sol 6V6GT reissues only lasted 6-8 months before I audibly heard some tonal degradation. The JJ 6V6S tubes would give me 12-18 months. But the Tung Sol's sounded a little sweeter. Does anyone know the plate voltages of the HDRX 20? I'm interested in knowing "how hard" that amp is on power tubes.

I doubt I'll go NOS on this amp. But having only 5 tubes and as easy as it is to bias them, it seems like a good amp to expirament with tubewise.
 
DreamTheaterRules said:
Great choice, many consider it the best non NOS PI tube for many amps. Especially if you push the PI stage, as it breaks up very nicely!
Click to expand...
50's Tweed Bassmans, Marshalls and the HDRX 20 use 12ax7 there,

But Blackface Fenders, which have a cleaner, less aggressive sound, use a 12at7.

Less gain. Less drive. A different sound.
 
Three weeks since I last posted.....

I started hearing some power tube degradation. It was that low muffled scratchy/white noise sound for a split second as a picked single note fades. It didn't start happening until I've bern playing loud for 10-15 min, ie once the tubes got good and hot. I recognized this right off.. it's the same thing that happened with two consecutive sets of new Tung Sol 6V6s in another amp, after 6-9 months. I got my HDRX 20 new in May, who knows how long it was in the store before I bought it, so the tubes could easily have 9 months on them. I did check the bias and it was still right around 29.

Bought a new full compliment of JJ's from Eurotubes. Matched pair of 5881s, I got a E83CC for V1, a ECC83 for V2 and a ECC803S for V3, all balanced. Popped them all in, biased it up to 29, played it loud for 30 min, rechecked the bias.

Amp sounds great! I think it sounds a little tighter, maybe a micro tad less bright, and a touch crunchier. What I did notice, which is way cool, is when both channel volumes are maxed and you hit a big note, it fades into a harmonic, almost feedback like. Way Hendrixy!

Two notes. I emailed PRS inquiring about the plate voltage. I wanted to know what it was. They didn't give me a number, but said its rather low. The amp doesn't blast the power tubes very hard. And the 3 preamp tubes that shipped in my amp were Genelex Gold Lions, but had Made in China printed on them. I thought Gold Lions were Russian?

PS: the Scumback H55(16 ohm, 65 watt) KILLS with this amp!
 
bigben55 said:
. And the 3 preamp tubes that shipped in my amp were Genelex Gold Lions, but had Made in China printed on them. I thought Gold Lions were Russian?
Click to expand...
The standard Gold Lions are Chinese, but they have a premium version that is made in Russia. They’re both good tubes, in my limited experience with them.
 
bigben55 said:
Three weeks since I last posted.....

I started hearing some power tube degradation. It was that low muffled scratchy/white noise sound for a split second as a picked single note fades. It didn't start happening until I've bern playing loud for 10-15 min, ie once the tubes got good and hot. I recognized this right off.. it's the same thing that happened with two consecutive sets of new Tung Sol 6V6s in another amp, after 6-9 months. I got my HDRX 20 new in May, who knows how long it was in the store before I bought it, so the tubes could easily have 9 months on them. I did check the bias and it was still right around 29.

Bought a new full compliment of JJ's from Eurotubes. Matched pair of 5881s, I got a E83CC for V1, a ECC83 for V2 and a ECC803S for V3, all balanced. Popped them all in, biased it up to 29, played it loud for 30 min, rechecked the bias.

Amp sounds great! I think it sounds a little tighter, maybe a micro tad less bright, and a touch crunchier. What I did notice, which is way cool, is when both channel volumes are maxed and you hit a big note, it fades into a harmonic, almost feedback like. Way Hendrixy!

Two notes. I emailed PRS inquiring about the plate voltage. I wanted to know what it was. They didn't give me a number, but said its rather low. The amp doesn't blast the power tubes very hard. And the 3 preamp tubes that shipped in my amp were Genelex Gold Lions, but had Made in China printed on them. I thought Gold Lions were Russian?

PS: the Scumback H55(16 ohm, 65 watt) KILLS with this amp!
Click to expand...

Great re-tube!

I think I need to get some of those Scumbacks. The best Celestion option I have for the HDRX (and my Smallbox) is a V30/Creamback 75 in my HDRX 2x12. Sounds great, but I’d just like to see what the real deal (short of vintage GB’s) is like.
 
Scumback makes the best classic Celestion type speakers. I emailed Jim w/Scumback after filling out his form and as usual, he was dead on right in his recommendation. I think he said, for an open back cab like mine, the H55 was the one if you primarily played single coil guitars, and the H55-PVC if you primarily played humbuckers. Both 65 watters.

andy474x said:
I think I need to get some of those Scumbacks. The best Celestion option I have for the HDRX (and my Smallbox) is a V30/Creamback 75 in my HDRX 2x12. Sounds great, but I’d just like to see what the real deal (short of vintage GB’s) is like.
Click to expand...
 
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andy474x said:
Great re-tube!

I think I need to get some of those Scumbacks. The best Celestion option I have for the HDRX (and my Smallbox) is a V30/Creamback 75 in my HDRX 2x12. Sounds great, but I’d just like to see what the real deal (short of vintage GB’s) is like.
Click to expand...
The Celestion Heritage Made In England G12H30 is also excellent. It's what I use in my Matchless 1:12 with my HDRX 20. I like the 75 Hz version. 8 ohms in a 1:12 cab.
https://imgur.com/H4Z6Vhl
https://imgur.com/NDkt4iU
 
I've been playing for a while and have had many Celestion speakers. Greenbacks, Vintage 30, 12-65, Creambacks, Neo Creambacks, A type, V Type, and in general, the G12H30 70th Anniversary has been my favorite. But they were never perfect. Amp dependant, they either had too harsh of highs, or too boomy of lows. I've tried several "improved" versions of that speaker, including the Mojotone BV30, Eminence Wizard, WGS Reaper & Reaper HP. Often better, sometimes worse, they all still had "something" I didn't love. So I bit the bullet and got a Scumback H75. Now THATS a speaker! Same G12H30 general EQ tonality, but refined. Big bass but not boomy or woofy, ample but smooth highs, loud, sounds great clean or crunchy. But the main thing is the immediacy of it. Notes are popping out thru the speaker before you're even done picking them! That H75 is in a different amp, and it might as well be welded in there!

I did test run the HDRX 20 thru that combo cab, and it did sound killer. The H55, with the 55hz bass cone, adds back the touch of bass lost from me running a small open back cab, and subtracts a touch of highs(which the HDRX 20 has plenty of already). Speaker choice is subjective, and i view it as the last "fine tunement" of an amps inherant EQ. For strat players of the HDRX 20, I don't think you can do much better.
 
bigben55 said:
I've been playing for a while and have had many Celestion speakers. Greenbacks, Vintage 30, 12-65, Creambacks, Neo Creambacks, A type, V Type, and in general, the G12H30 70th Anniversary has been my favorite. But they were never perfect. Amp dependant, they either had too harsh of highs, or too boomy of lows. I've tried several "improved" versions of that speaker, including the Mojotone BV30, Eminence Wizard, WGS Reaper & Reaper HP. Often better, sometimes worse, they all still had "something" I didn't love. So I bit the bullet and got a Scumback H75. Now THATS a speaker! Same G12H30 general EQ tonality, but refined. Big bass but not boomy or woofy, ample but smooth highs, loud, sounds great clean or crunchy. But the main thing is the immediacy of it. Notes are popping out thru the speaker before you're even done picking them! That H75 is in a different amp, and it might as well be welded in there!

I did test run the HDRX 20 thru that combo cab, and it did sound killer. The H55, with the 55hz bass cone, adds back the touch of bass lost from me running a small open back cab, and subtracts a touch of highs(which the HDRX 20 has plenty of already). Speaker choice is subjective, and i view it as the last "fine tunement" of an amps inherant EQ. For strat players of the HDRX 20, I don't think you can do much better.
Click to expand...
How much $$$ for one?
 
bigben55 said:
They're definitely not cheap, as they're built to order. I wanna say they were $189+$30 for shipping????
Click to expand...
That doesn't seem too bad. The Celestion G12H30's I like and which are made in England (not China...) are selling for about the same. $200.

A great guitar speaker is the last link in the chain. It's the voice your ears finally hear.

If a guitar pickup is worth $100 - 200, so is a great guitar speaker.
 
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