Tweaking the HXDA 30

László

Too Many Notes
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Apr 26, 2012
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Today I re-watched David Grissom's demo of the DG50 amp, and I thought it wasn't all that dissimilar to my former 50 watt HXDA. So I decided to experiment a bit, to see if I could get similar tones with my HXDA 30 Watt.

I'm still using the PRS Pine 1x12 cab with the amp, as it'll be a little while before I can add a second DG 2x12 cab. But I thought, why not isolate the 1x12 the way I do the DG cab, get it off the floor using an isoacoustics stand, and absorb some of the omnidirectional bass room modes and standing waves with one of my gobos? So I set it up on the stand, and put the gobo just behind it, so I could concentrate only on the sound that was coming from the speaker, and not additional sound bouncing off the floor and rear walls. The stand raises the speaker up about 7 or 8 inches, and tilts it back a little. Here's a shot of the setup for today:



One thing that is relatively new on the DG30 that I probably haven't spent enough time with is that I swapped the preamp tubes, putting in a NOS Mullard 12 AX7 in V1, and new JJ gold pins in the other spots, as the stock ones had gone a bit microphonic. While I did report earlier on a marked improvement, I hadn't had time to experiment much after installing these tubes. These had all been tested for microphonics, noise and balanced triodes as part of my order, and they were stellar examples with excellent measurements - and dead quiet with no audible microphonic problems.

The stock Winged C output tubes remain in the amp, as they're good sounding and aren't the least bit noisy. I do have a pair of NOS Siemens tubes for down the road.

I literally tried the amp exactly the way Grissom set up his DG50. I set the mids and bass on 4, and the bass on 6. I set the gain around 6 for the HXDA gain, and though the DG 50 doesn't have a separate bass gain control, I experimented until I got very close to his sound with it. I set the switches to HX, DA, and DA, and the presence at about 11 o'clock. The Master was up all the way.

I was playing my McCarty Singlecut today, and while it isn't a DGT obviously, I was able to dial in similar tones on the guitar, so I used Grissom's guitar settings, give or take here and there. Really, it was just a matter of experimenting, and tweaking back and forth. Took me about 15 minutes to dial in a basic tone, and then I tweaked my clean boost and OD pedals to sound a lot like what Grissom did in the video with his tone.

No, I'm not trying to cop Grissom's tone. What I wanted to do was experiment a bit with the capabilities of the amp, just to see how close I could come. And the answer is, I was able to come very close. No, it wasn't exact - heck, the gear is very different! But the basic qualities were there, and I was pretty excited to be able to explore those tones on my gear.

I did come away feeling that the HXDA 30 is perhaps more versatile than I'd previously thought, and that the PRS pine 1x12 sounded better than I'd heard it sound in the past, when the most I'd done with it was set it on an Auralex Gramma. The Auralex platform is cool, and does eliminate some of the audible vibrations in the room, but it isn't nearly as open sounding and clear on that as it was on the Isoacoustics stand.

In any event, it was a fun couple of hours. I won't keep the amp set up that way (as I said, I'm not about to chase someone else's tone) but it was a very worthwhile thing to explore the amp's potential once again.

I should add that it was also a lot of fun!
 
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Very interesting, Les. I'll have to check out that video.

Have you ever bought tubes from Antique Electronic Supply? I'm about to place my first order from them to retube my old JCM 800.
 
Very interesting, Les. I'll have to check out that video.

Have you ever bought tubes from Antique Electronic Supply? I'm about to place my first order from them to retube my old JCM 800.

I haven't bought from them yet. What have you got planned?
 
Their website is www.tubesandmore.com

The amp is a 50 watt single channel JCM 800, which I've owned forever.

I am getting a matched pair of Mullard Reissue EL34, and possibly three Mullard 12AX7/ECC83. I am also considering using the Mullard in the first spot and two Tung Sol Reissue 12AX7 for the other spots.
 
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I'm pretty sure they are new. They are made in Russia. I think NOS were made in the UK.
 
Gotta say this...the HXDA 30 with these settings sounds absolutely stellar with the DG Custom 2x12 cab, as it did with my usual settings. The DG cab is just so tasty!

The 1x12 is s nice cab, no doubt, but the bigger cab is absolutely awesome with this amp.
 
Yup. NOS were Blackburn, England. What's in the amp now?

Well, it's a good thing you asked me that before I placed my order. I hadn't removed the cover from the back yet. I thought the amp should have EL34 tubes in there, but it has a pair of General Electric 6550 tubes in it. I'd better start looking at 6550 tubes. The preamp tubes are all Raytheon 12AX7/EC833. This amp was built in 1982.
 
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Raytheons have a fantastic reputation in the NOS world. There's no way I'd replace them with new-manufacture preamp tubes unless they don't work or have gone microphonic!! NOS JAN Raytheons go for $250 each at places like The Tube Store. I paid less than that for an NOS Mullard 12AX7/ECC83.

The good thing about preamp tubes is that they last pretty much forever compared to power tubes.

Personally, I'd keep the preamp tubes (assuming they're good) and go NOS for the 6550s, because the old ones were highly regarded. NOS GEs go for $100 apiece, but they're the real deal.
 
Raytheons have a fantastic reputation in the NOS world. There's no way I'd replace them with new-manufacture preamp tubes unless they don't work or have gone microphonic!! NOS JAN Raytheons go for $250 each at places like The Tube Store. I paid less than that for an NOS Mullard 12AX7/ECC83.

The good thing about preamp tubes is that they last pretty much forever compared to power tubes.

Personally, I'd keep the preamp tubes (assuming they're good) and go NOS for the 6550s, because the old ones were highly regarded. NOS GEs go for $100 apiece, but they're the real deal.

Thank you, Les. I will only change the power tubes. Can you please recommend where I should look for the NOS GEs? I didn't find them on the sites I've been looking at.
 
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Thank you very much. I ordered a set and I will wrap them and label them "To: me, From: my wife" for xmas.
:biggrin: haha, now that is how to ensure that I will like my gift.
She has no idea, by the way...:flute:
 
Thank you very much. I ordered a set and I will wrap them and label them "To: me, From: my wife" for xmas.
:biggrin: haha, now that is how to ensure that I will like my gift.
She has no idea, by the way...:flute:

Haha! I pretty much do that!

My last birthday, my wife asked what I was going to buy myself, so she could get me something I wouldn't get myself. LOL
 
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Haha! I pretty much do that!

My last birthday, my wife asked what I was going to buy myself, so she could get me something I wouldn't get myself. LOL

hahaha...We are birds of a feather! I'm sorry that I hijacked your thread, by the way.
 
Is there any such thing as a real hijack at the communal gear trough? I think not.

My first PRS was a Christmas gift from Mrs. B, a bunch of years ago. It's been down hill from there. :biggrin:
 
My first PRS was a Christmas gift from Mrs. B, a bunch of years ago. It's been down hill from there. :biggrin:

You are a lucky man, Mr. B.

My wife would never, ever buy me a guitar. It's not something that would even cross her mind!

She's gifted me with some very nice stuff. But never an instrument. Maybe she figures that's my department. Come to think of it, though, it's probably better that she has never bought me a PRS. Because if she went shopping for one, I think she'd freak out to discover they cost more than $800.... ;)
 
My wife has only ever bought me one instrument, and she asked me first. She's told me that she wouldn't do something like that, because it's not something she feels she can - or should - do since there's so much personal preference.

I keep dropping her hints and telling her it's not guessing if I tell her what I want...
 
My wife has only ever bought me one instrument, and she asked me first. She's told me that she wouldn't do something like that, because it's not something she feels she can - or should - do since there's so much personal preference.

I keep dropping her hints and telling her it's not guessing if I tell her what I want...

My problem is that if I told her what I wanted, and she bought it, she'd find out how expensive what I want really is!!!
 
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