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

RickP

Established 1960, Still Not Dead
Joined
Dec 10, 2019
Messages
6,487
Location
Gulf Coast of Texas
Ok, after totally hijacking Rapdog’s HXDA market thread, I thought it was time to get back in my own lane!

A 50 watt version HXDA head is “Out For Delivery” to my humble abode, and the obligatory pics will follow soon. I am looking forward to it as it’s as close to an old Plexi as I am ever likely to get, and I’ve been really into those crunchy, less than Mesa-level gain tones of late (caveat being the California Tweed, which is making some absofreakinglutely gorgeous Fender tones in the BandCave).

I’ve received some great info on the HXDA from some experienced Brit-gain Jedis, and would love it for anyone to share anything HXDA related: settings of pots and switches, cabinets you’ve loved and hated with the HXDA, same thing with pedals, certain guitars/pickups. As mentioned elsewhere, the sole documentation I have found in print is a tube chart. Like the old Plexi, a very simple and direct circuit, it appears. The only production amp I have ever experienced that has, apparently, no manual at all. Very much like a custom made amp. Exciting, strangely enough.

If there is a lot of input, I’ll change the title to something other HXDA newbies can come to and find a repository of HXDA lore, info, and insights. I’ll start with some things...

This is the tube chart for the 30 and 50 watt models. Identical, so the down-rating to lower wattage is a function of something elsewhere in the circuit.

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A video with Paul discussing the HXDA original:


and Greg Koch being blown away by it while Doug Sewell marvels at the tones and playing:



Come on, FedEx.
 
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It’s here! I took it out, hooked it up to a 2x12 cab with UK Greenbacks in it, and banged out a few chords... oh, man. Round, snarling, and just right. Amazing for a quick dial in. Going to spend some proper time on it over the next few days. It came with two Winged C, SED EL34s. I’m sure that ain’t hurting the tone any!

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Pu4SPYr.jpg

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That’s a beauty, Rick. I love your cabinet, too.

Those Winged C tubes are as good as it gets. I love them. I put three Genalex Gold Lion 12AX7 in my head and they are really good with the Winged C.
I need to get some good 12AX7s. This has JJs in it, which are ok but have never been my favorites. I’ll be shopping. :rolleyes:
 
Discovery of the day: The HXDA through a 2x12 greenback cab, with a 594 Soapbar gets some pretty damn authentic sounding ZZ Top and Leslie West kind of tones! It’s a bit looser, more springy/woody sound, and it kicks ass on songs like Just Got Paid or The Beer Drinkers & Hell Raisers solo.

Next up... the 72 SG.
 
Actually, you haven't lived until you've used the HXDA with NOS Mullard 12AX7s and either the NOS Mullard or Siemens EL34s, but I digress.

I'll post a pic of my current setting shortly.
Totally agree. I took your advice and put those in mine (which now belongs to toothace)
 
Ok, Gurus...

I realize this is a taboo question on some forums, but can anyone share their EL34 bias setting? Once I get to a lull in playing, I’ll be checking all those things. I can just use the standard 65-70% of max EL34 numbers, but wondered if anyone has a favorite. I have SED/Winged C/Real Svetlanas in there, and will likely keep them as I am enjoying the tone.
 
Ok, Gurus...

I realize this is a taboo question on some forums, but can anyone share their EL34 bias setting? Once I get to a lull in playing, I’ll be checking all those things. I can just use the standard 65-70% of max EL34 numbers, but wondered if anyone has a favorite. I have SED/Winged C/Real Svetlanas in there, and will likely keep them as I am enjoying the tone.

I think mine are biased to about 30.
 
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