HX/DA INFO (and my NAD 50 W Head(s)) Share your HXDA knowledge with the world!

The Mike Ault video is what sold me on the amp. In the photo without the fuses, maybe they simply took a pic of the amp while it was being built or serviced?
Could be! I couldn’t see any other differences. There is some wording there, but the resolution isn’t good enough to read all of it.
 
I've never removed the chassis in mine to know how many fuses it has. I wish I could be of more help. Also, there are 30W versions. Maybe they only use two fuses?
 
I've never removed the chassis in mine to know how many fuses it has. I wish I could be of more help. Also, there are 30W versions. Maybe they only use two fuses?
I just ran into a thread you did in 2016 that had a great video and a insides picture of a 30 watter... 4 fuses! Must have been a assembly pic. The thread is here:

https://forums.prsguitars.com/threads/wiring-in-prs-amp-lines.18807/

Video here:

The first briefly touched on those fuses... should be 4!

Burn in... amp sounds awesome.

Also, confirms 30 is the right bias setting for these.


@LSchefman I believe I should have titled this thread as “what I found that Les already found, and a few other things!” You’ve been in most of the searches I’ve made sooner or later. Good work, my friend!
 
Last edited:
Universal Audio Ox Amp Top Box

Or the short version, The Panacea Box.

I moved some things around and hooked the HX/DA to the Ox Box, out to the 2x12 cab, and also to the mixer using the Ox Box line outs and the Ox app to assign speaker cab, room, mics, and FX/processing to the mixer sends. Man, it sounds awesome together. Listening to the dry cab and the effected mixer sound through Presonus Scepter S8s, the sound is immense. Adding some room mics in the Ox to get that Led Zep “The Ocean” sound, using the incredible reverbs... lovely.

And you can crank the amp to any level to get what you want! I love the Ox Box, it has been the perfect solution for every amp over 10 watts that I use. Power Panacea. I might buy and sell some amps, but the Ox has a home here. It would make a 100 watt HX/DA a totally useable proposition.

For those who may not know, the Ox Box has outputs to a speaker cabinet(s), two line outs to mixer/DAW/FOH, and a headphone out. Each one has it’s own volume control; a six-step attenuator on the speaker cab, and a normal potentiometer on line and headphone outputs. You can use all of them at the same time.

It is an investment, but so much more than an attenuator. And with an amp that has more horsepower than your ears, or those in your household, can safely or sanely listen to at it’s best settings, it is a life/hearing/recording/marriage saver. You really have to try it to see what it can do. If you just play at home, never record or run through a PA, a regular power soak attenuator will do, but if you do use any of the above methods of performance, the difference in quality of experience is night and day.

Result: HX/DA plus Ox Box is a total win.
 
Last edited:
Universal Audio Ox Amp Top Box

Or the short version, The Panacea Box.

I moved some things around and hooked the HX/DA to the Ox Box, out to the 2x12 cab, and also to the mixer using the Ox Box line outs and the Ox app to assign speaker cab, room, mics, and FX/processing to the mixer sends. Man, it sounds awesome together. Listening to the dry cab and the effected mixer sound through Presonus Scepter S8s, the sound is immense. Adding some room mics in the Ox to get that Led Zep “The Ocean” sound, using the incredible reverbs... lovely.

And you can crank the amp to any level to get what you want! I love the Ox Box, it has been the perfect solution for every amp over 10 watts that I use. Power Panacea. I might buy and sell some amps, but the Ox has a home here. It would make a 100 watt HX/DA a totally useable proposition.

For those who may not know, the Ox Box has outputs to a speaker cabinet(s), two line outs to mixer/DAW/FOH, and a headphone out. Each one has it’s own volume control; a six-step attenuator on the speaker cab, and a normal potentiometer on line and headphone outputs. You can use all of them at the same time.

It is an investment, but so much more than an attenuator. And with an amp that has more horsepower than your ears, or those in your household, can safely or sanely listen to at it’s best settings, it is a life/hearing/recording/marriage saver. You really have to try it to see what it can do. If you just play at home, never record or run through a PA, a regular power soak attenuator will do, but if you do use any of the above methods of performance, the difference in quality of experience is night and day.

Result: HX/DA plus Ox Box is a total win.
I can validate this as I have first hand hearing knowledge during a 594 shoot out at MA Pete's back in February. The Ox is an absolute game changer.
 
More test material arrived today...

5484b8A.jpg
 
Universal Audio Ox Amp Top Box

Or the short version, The Panacea Box.

I moved some things around and hooked the HX/DA to the Ox Box, out to the 2x12 cab, and also to the mixer using the Ox Box line outs and the Ox app to assign speaker cab, room, mics, and FX/processing to the mixer sends. Man, it sounds awesome together. Listening to the dry cab and the effected mixer sound through Presonus Scepter S8s, the sound is immense. Adding some room mics in the Ox to get that Led Zep “The Ocean” sound, using the incredible reverbs... lovely.

And you can crank the amp to any level to get what you want! I love the Ox Box, it has been the perfect solution for every amp over 10 watts that I use. Power Panacea. I might buy and sell some amps, but the Ox has a home here. It would make a 100 watt HX/DA a totally useable proposition.

For those who may not know, the Ox Box has outputs to a speaker cabinet(s), two line outs to mixer/DAW/FOH, and a headphone out. Each one has it’s own volume control; a six-step attenuator on the speaker cab, and a normal potentiometer on line and headphone outputs. You can use all of them at the same time.

It is an investment, but so much more than an attenuator. And with an amp that has more horsepower than your ears, or those in your household, can safely or sanely listen to at it’s best settings, it is a life/hearing/recording/marriage saver. You really have to try it to see what it can do. If you just play at home, never record or run through a PA, a regular power soak attenuator will do, but if you do use any of the above methods of performance, the difference in quality of experience is night and day.

Result: HX/DA plus Ox Box is a total win.
Absolutely spot on.
 
Universal Audio Ox Amp Top Box

Or the short version, The Panacea Box.

I moved some things around and hooked the HX/DA to the Ox Box, out to the 2x12 cab, and also to the mixer using the Ox Box line outs and the Ox app to assign speaker cab, room, mics, and FX/processing to the mixer sends. Man, it sounds awesome together. Listening to the dry cab and the effected mixer sound through Presonus Scepter S8s, the sound is immense. Adding some room mics in the Ox to get that Led Zep “The Ocean” sound, using the incredible reverbs... lovely.

And you can crank the amp to any level to get what you want! I love the Ox Box, it has been the perfect solution for every amp over 10 watts that I use. Power Panacea. I might buy and sell some amps, but the Ox has a home here. It would make a 100 watt HX/DA a totally useable proposition.

For those who may not know, the Ox Box has outputs to a speaker cabinet(s), two line outs to mixer/DAW/FOH, and a headphone out. Each one has it’s own volume control; a six-step attenuator on the speaker cab, and a normal potentiometer on line and headphone outputs. You can use all of them at the same time.

It is an investment, but so much more than an attenuator. And with an amp that has more horsepower than your ears, or those in your household, can safely or sanely listen to at it’s best settings, it is a life/hearing/recording/marriage saver. You really have to try it to see what it can do. If you just play at home, never record or run through a PA, a regular power soak attenuator will do, but if you do use any of the above methods of performance, the difference in quality of experience is night and day.

Result: HX/DA plus Ox Box is a total win.

I don't have one (have friends who do), but they sure sound great. I'd unhesitatingly get one if the right project came through the door.

I'm a fan of UA gear, anyway; have had their mic preamps, compressors, an Apollo, lots of their plugins. Everything is top drawer, and gets used on major label records all the time. You simply can't go wrong with their gear.
 
Sunday Discoveries:

While working with the HX/DA and Ox Box setup today, I was really having a great time seeing how many sounds and textures I could get with just a guitar (the HB Spruce). Between two pickups, a 3-way selector switch, and one each volume and tone controls, it is pretty impressive. Having been one of those multi-channel, multi-drive-pedal people for years, this is new and fun ground for me. I'm enjoying it.

I noticed my headphones, just a standard Sony MDR-7506 set, sitting on my mixer and wanting to get in on the fun. Plugged into the Ox, the sound is really nice and clear (and loud, so be careful!). Then I remembered I could turn down the speaker and mains volumes. How cool! Zero noise outside but the acoustic sound of the guitar, and a raging Plexi in each ear, complete with all the Universal Audio niceness on it. I went back to look at the manual and found two things that are worth pointing out.

1. You don't have to have a speaker cabinet at all. The Ox provides a resistive load to your amp, so it is safe to use without one. I couldn't remember if it was just optional to turn the cab output to zero or not have one at all, but the manual confirmed all outputs are optional. The things this could open for many people is mind-boggling. If your primary thing is recording, you could lose the speaker cabs altogether if you like the way the Ox speaker sims sound... and they're impressive. Or for the late night jam while the kids are asleep. Glorious.

2. When I bought the Ox Box, the footswitch connection was a "future development" thing. I just discovered it is now operational, and you can use a 1, 2, or 3 button footswitches to control effects in the Ox, and assign them via the app. Serious performance enhancement there. Maybe I should read the online manual more often. Actually, I do visit the UA forums on occasion, but the inccesant whining about "this is crap because my Zulu 1758 loaded, laser aligned cabinet isn't included in the models" and such. Again, I need get over it, and keep up.

While not necessarily HX/DA specific, the opportunities to expand what you can do with the HX/DA or any other amp up to 150 watts warrants including it here. For those who only need the amp head tone, but not the cabinet volume, the savings from not buying a cab could pay for an Ox Box. Either way, it's a heck of a lot of fun to use.
 
Monday Funday

I got to put the Siemens EL34s in today. They sound, as expected, great in the HX/DA. They are NOS, so I am going to use them for a bit and let them wear in some. They look to be very well constructed, as I've come to expect of most electronic things made in Germany.

Early impressions are very good, comparing them with the Winged C EL34, which is high praise as I consider the Winged Cs to be the best sounding guitar tubes made over the last 30 years. As far as I know, neither of these are currently made and NOS or used is the only way you're getting them now.

Where they are similar: Quality of the sound, plain and simple. They never seem to be out of control or on the ragged edge. No matter how hard I push them in this amp, both retain a good tone and sound as though they could do this for weeks on end. The drive tones are especially lively, and have a dimensional character that kind of makes you want to play them loud. I especially like that neither sounded buzzy, fuzzy, or thin. You know how some amps start to sound like paper tearing when you crank them up? None of that here.

Where they are different: While either will do a bit of what the other shines at, they are different. The best way I can describe it is to say the Winged C is classic Plexi, full of controlled top end that has that great sizzle to it. The low end is there, but it's those sweet mids and highs that you notice right away. The Siemens, on the other hand, has a slightly cleaner and tighter sound, especially in the bottom, that sounds authoritative. They have a punchiness that reminds me of a cranked Hiwatt DR103... a real ground shaker. Like the Winged C, it never sounds like it's breathing hard.

Conclusion: I now, finally, have a tube I can feel as confident in as the Winged C EL34. I'm going to add a few more pairs to my tube shelf while they can still be had for a decent price. At this moment I am not sure which set I'll leave in, and that is not something I have said since the 90s when I started using what was then called Svetlana tubes. Each set makes me want to play a bit differently, and I am enjoying both. If you haven't tried the Siemens tubes, and you're looking for something to tame a raging EL34 amp without sucking out its soul, this might be the ticket. They are some of the more musical EL34s I've heard.

Thanks to @LSchefman for the tip! Now, on to preamp tubes...
 
By the way, I am playing way too loud. I can turn it down with the Ox Box, but I’m living that Gilmour quote “You know, once you've had that guitar up so loud on the stage, where you can lean back and volume will stop you from falling backward, that's a hard drug to kick.”

I will rein it in, though. Somehow, I still have good hearing, and I need to keep it. But man, does it sound awesome!
 
Monday Funday

I got to put the Siemens EL34s in today. They sound, as expected, great in the HX/DA. They are NOS, so I am going to use them for a bit and let them wear in some. They look to be very well constructed, as I've come to expect of most electronic things made in Germany.

Early impressions are very good, comparing them with the Winged C EL34, which is high praise as I consider the Winged Cs to be the best sounding guitar tubes made over the last 30 years. As far as I know, neither of these are currently made and NOS or used is the only way you're getting them now.

Where they are similar: Quality of the sound, plain and simple. They never seem to be out of control or on the ragged edge. No matter how hard I push them in this amp, both retain a good tone and sound as though they could do this for weeks on end. The drive tones are especially lively, and have a dimensional character that kind of makes you want to play them loud. I especially like that neither sounded buzzy, fuzzy, or thin. You know how some amps start to sound like paper tearing when you crank them up? None of that here.

Where they are different: While either will do a bit of what the other shines at, they are different. The best way I can describe it is to say the Winged C is classic Plexi, full of controlled top end that has that great sizzle to it. The low end is there, but it's those sweet mids and highs that you notice right away. The Siemens, on the other hand, has a slightly cleaner and tighter sound, especially in the bottom, that sounds authoritative. They have a punchiness that reminds me of a cranked Hiwatt DR103... a real ground shaker. Like the Winged C, it never sounds like it's breathing hard.

Conclusion: I now, finally, have a tube I can feel as confident in as the Winged C EL34. I'm going to add a few more pairs to my tube shelf while they can still be had for a decent price. At this moment I am not sure which set I'll leave in, and that is not something I have said since the 90s when I started using what was then called Svetlana tubes. Each set makes me want to play a bit differently, and I am enjoying both. If you haven't tried the Siemens tubes, and you're looking for something to tame a raging EL34 amp without sucking out its soul, this might be the ticket. They are some of the more musical EL34s I've heard.

Thanks to @LSchefman for the tip! Now, on to preamp tubes...

I would describe the Siemens tubes exactly as you did. Spot-on!

I wound up preferring that tighter sound of the Siemens to the looser sound of the Winged C, and bought a few more sets 'just in case'. They also settle in nicely, so you might want to let that happen, as the tone actually improves!

:)
 
I would describe the Siemens tubes exactly as you did. Spot-on!

I wound up preferring that tighter sound of the Siemens to the looser sound of the Winged C, and bought a few more sets 'just in case'. They also settle in nicely, so you might want to let that happen, as the tone actually improves!

:)
That’s great to hear, especially as good as they sound right off. I’m impressed with them, and will definitely be using them. I was doing some Eagles lead work, and found the Siemens tubes let me get that clear drive tone that sits so well in that music. Really enjoyable!
 
That’s great to hear, especially as good as they sound right off. I’m impressed with them, and will definitely be using them. I was doing some Eagles lead work, and found the Siemens tubes let me get that clear drive tone that sits so well in that music. Really enjoyable!

I wish I could take credit for discovering the Siemens tubes, but I was tipped off about them by Doug Sewell, who designed the HXDA. All credit to him.
 
I wish I could take credit for discovering the Siemens tubes, but I was tipped off about them by Doug Sewell, who designed the HXDA. All credit to him.
I’ve heard about Siemens tubes on occasion, normally in NOS tube conversations or articles, but now I wonder why they aren’t more highly recognized, especially in the EL34 world, which I think has been harder to find quality tubes than the 6L6GC. This is really something. We need to keep it secret until I can stock up! :rolleyes:
 
Last edited:
Some more HXDA lore from PRS home site:

HXDAAmpBlog.jpg

Much like the DG Custom’s nod to vintage amp design, the HXDA also delivers a fantastic vintage tone. However, the DG Custom and HXDA vary greatly in the style in which they are built and voiced. The amp is British-inspired and voiced to rock the iconic tones of the late 60’s and early 70’s. The medium-gain tone of the HXDA is smooth, fat, singing, and just plain musical. The amp features three HX / DA mini toggles that all play a part in shaping the tone and gain of the amp.

The HXDA is offered in a 30-watt and 50-watt head.
 
Back
Top