PRS HXDA 30W Combo

Discussion in 'Amplifiers' started by Em7, Jul 4, 2018.

  1. Em7

    Em7 deus ex machina

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    It is no secret that the HXDA is my favorite PRS amp by a large margin. Doug, Paul, and the guys in the amp shop got this amp right. It has the tonal magic and response that trips my trigger. I would love to own a 30W combo, but at close to $4K with twin daughters entering college in the fall, it is just not going to happen in the near future. If you own an HXDA 30W combo, post it!
     
    #1 Em7, Jul 4, 2018
    Last edited: Jul 5, 2018
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  2. jxe

    jxe babe en der wood

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    post it to your address?
     
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  3. toothace

    toothace At least I'm good at dentistry

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    Here she is
    [​IMG]

    With the 25W Archon combo
    [​IMG]
     
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  4. bodia

    bodia Authorities said.....best leave it.....unsolved

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    I recognize that HX/DA!
     
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  5. LSchefman

    LSchefman Hears Tones

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    I have the 30W head. Not exactly what you asked for, but I figured I’d join the party anyway.

    [​IMG]
     
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  6. Em7

    Em7 deus ex machina

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    The thing that I like about the HXDA is that it is basically a 5F6A Tweed Bassman on steriods. The older Marshalls are to the 5F6A Tweed Bassman what Italian-American food is to real Italian food. Just as Italian-American food is an adaptation of traditional Italian recipes and cooking techniques to domestic ingredients, the JTM Marshalls are an adaptation of the 5F6A circuit to domestic parts. The JMP Marshalls are step-wise refinements on the JTM Marshall. The overdriven tones given by the use of of EL34s and 12" speakers were a happy accident because Jim Marshall was going for a big, clean sound.

    The thing that makes the HXDA sound like it does had to be result of Jim Marshall attempting to limit production costs. The bandwidth of the output transformer is horrible. It cannot produce full bandwidth at full power. That is why the amp obtains the midrange-thick growl as you crank it up. The transformer is rolling off higher-order harmonics. That is not uncommon in the amp world. Most of the coveted Fender guitar amps have undersized output transformers. That was just Leo being frugal. However, where Jim Marshall got it right is reducing the size of the coupling capacitors and increasing the capacitance in the power supply, so the amp does not get "farty" like a lot of Fender amps. Leo scooped out the mids in the first two gain stages on the blackface (BF) amps; however, the remaining interstage coupling capacitors are still just too large. Paul Rivera made his name in the seventies and early eighties fixing the coupling cap problem on Princetons and Deluxes that were used by LA studio artists such as Jay Gradon and Dean Parks (he also blackfaced silverface amps). I personally cannot understand how anyone with ears can say that a non-modified BF Deluxe is a good pedal platform, at least not when it comes to distortion pedals. That amp only sounds good with distortion pedals that have a huge midrange hump in their equalization curves like the Tube Screamer. Most pedals that sound good with a tweed-based amp sound like ice picks when used with a BF amp. In my humble opinion, the BF Deluxe and the BF Princeton are the most overrated amps in the history of guitar. These amps do not hold a candle to their brownface counterparts. The brownface amps are transitional designs that moved both of these amps to fixed-bias 2x6V6 power stages from cathode-biased single 6V6 (Tweed Princeton) and 2x6V6 (Tweed Deluxe) power stages without introducing the BF tonestack topology that loads down the preamp and sucks the life out of the amp tonally.

    Let's take a look at the Fender 5F6A Bassman and Marshall 1987 (50W Plexi) shematics.

    Fender 5F6A Bassman Circuit

    [​IMG]


    Marshall 1987 (50W Plexi) Circuit

    [​IMG]
    The topologies of the amps are basically identical. That is because Jim Marshall copied the Fender Tweed Bassman. The difference lies in a few tube and component swaps. However, in my humble opinion, the critical component value swap are the coupling capacitors between the phase inverter the power tubes. The Fender Bassman uses 0.1uF coupling capacitors between the phase inverter and power tubes whereas the 1987 uses 0.022uF. That reduction in capacitance raises the lowest frequency that is passed to the power tubes for amplification. Low frequencies require more power to create than higher frequencies because they require larger cone excursion (movement). This difference can be witnessed by looking at a hi-fi speaker with its grille removed. Watch how much the cone moves when a bass note is hit. While the lowest note on a guitar is 82 Hertz, sub-harmonics below this note are created by the amp. Blocking low frequencies tightens the bass response of the amp. There is less negative feedback and the feedback signal is taken from the 16-Ohm tap on the output transformer. The reduction in negative feedback allows the power stage to run more "open loop," which increases harmonic complexity at the expense of being more sensitive to the speaker cabinet into which the amp is plugged (i.e., lowering negative feedback decreases something known as "damping"). The 1987 Plexi Marshall also has three times the total capacitance that the 5F6A has in its power supply, making its power supply much "stiffer." The amp will still sag under heavy load, but nothing like a 5F6A Bassman with its tube rectifier and lower amount of capacitance. Jim Marshall basically invented rock tone by taking blues tone and removing a lot of the sag while adding the difference using power pentodes instead of beam tetrodes bring to the table.
     
    #6 Em7, Jul 5, 2018
    Last edited: Jul 5, 2018
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  7. 11top

    11top Cousin Eddie's cousin

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    I have a 50 watt head and can't seem to bond with it.
     
  8. Em7

    Em7 deus ex machina

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    I have never played the 50W, but the 30W is very nice. Most of the best sounding Marshall amps have power transformers that have lower secondary voltages, resulting in lower rectified plate and downstream voltages. However, in your case, it may be that you are looking for a harder-edged sound. I believe that you like the 50W Custom. I am not a fan of that amp, but I can appreciate that it is a transitional design between the original 2-Channels and the Archon.

    At this point, I only use a tube amp when I am looking for vintage tones. Those tones are the result of the inadequacies of tube technology, as much of what we like about tube tone is due to the non-linearity of the technology when pushed. I find myself using solid-state gear more and more these days. Why? It just does not make sense to use a tube amp when one uses a long chain of solid-state-based pedals in front of it. Tube amps are best used guitar -> cord -> amp; otherwise, one is choking off the dynamic response of the amp.
     
  9. DreamTheaterRules

    DreamTheaterRules Archon owning member

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    I loved the Custom 50, but only once it was turned up louder than I can usually play. It filled in and got FAT with a little volume. But it is not "my" or "one of my" tones unless I was playing a more bluesy gig. I had to push it with a boost that brightened it up some for it to come closer to my tonal preference. When I did that, it did it very well but again, once turned up a bit. (Timmy and SHO clone were great with it).

    I find the Archon goes straight to "my" kind of tone and sounds good at lower volumes than the C50 did. Turned up, both sound great but different. The NF3>Custom 50 would be a killer blues or blues rock gig setup.
     
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  10. shinksma

    shinksma What? I get a title?

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    I love my 30W HXDA Combo!

    (Looking for a matching ext 1x12 cab to make a mini-stack...harder to find than you'd think...yeah, one on Reverb now/recently, not the price I want to pay)

    [​IMG]
     
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  11. jtgblade

    jtgblade New Member

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    Nice amp. I´d like play someday this amp. PRS amps are amazing.
     
  12. Em7

    Em7 deus ex machina

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    My MC58 case would be right at home with that amp. :)

    I wonder how many HXDA amps Paul sold with this demo:



    I have heard and played the Foxy Lady introductory riff so many times that it is etched in my brain. I have never heard anyone get that close to the studio version of that riff. I love Paul's reaction.
     
    #12 Em7, Jul 5, 2018
    Last edited: Jul 6, 2018
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  13. jfb

    jfb Plank Owner

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    Hmmm....
     
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  14. CatStrangler

    CatStrangler PRS Enthusiast

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    I have a 2X12 combo that I love, I'll try to get a pic up soon.
     
  15. toothace

    toothace At least I'm good at dentistry

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    This! (Looking for one for the Archon also)
     
  16. Alnus Rubra

    Alnus Rubra Loving nature’s wonders

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    My guess - a lot!
     
  17. DreamTheaterRules

    DreamTheaterRules Archon owning member

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    Stupid question: Have you had it checked out to make sure it’s OK? Or do you think it sounds like it should but you just don’t care for it? Or...?
     
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  18. 11top

    11top Cousin Eddie's cousin

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    That’s actually a very good question. It’s a very early model. To me, it has a very harsh sounding overdrive. I tend to like a creamier sustain. It sounds very “biting” to me.
    I did have it looked at by a well-respected amp guy in Indy, and he seemed to think it was working properly.
     
  19. Em7

    Em7 deus ex machina

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    I played that song a metric truck load of times when I was in high school. :) I started playing electric guitar in 1976. Back then, Hendrix and Page where the guitarists to emulate. There were other good guitarists, but they did not hold the appeal to my teenage brain. When the debut Van Halen album hit the airwaves in 1978, it was like an alien had landed on Earth and changed guitar forever. The first time I hard "Running With The Devil" played on WIYY 98 Rock was truly a WTF just happened moment. That album spawned an entirely new era of rock, and the guitar tones that have resurfaced since Mike Matthews opened the gates to the former Soviet tube factories pretty much faded into oblivion along with the Les Paul until Slash pretty much saved that instrument from oblivion.

    What many guitarists do not know is that a lot of the really hot guitar tones in the eighties are not tube, or at least not all all-tube. In my humble opinion, solid-state technology excels at producing these tones. I dare anyone to listen to III Sides to Every Story, and tell me the tones that Nuno Bettencourt got out an ADA MP-1 suck. The ADA MP-1 may have had a pair of 12AX7As in it, but they were basically for show just like 12AX7As in the ADA power amp. Sure, they were used, but they were part of a mostly solid-state signal path. Here is the MP-1 preamp schematic:

    [​IMG]

    The Mesa V-Twin was also a preamp that incorporated solid-state technology:

    [​IMG]
     
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  20. DreamTheaterRules

    DreamTheaterRules Archon owning member

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    Interesting, as I haven’t heard those characteristics in HX/DA clips I’ve heard. I’m sure you didn’t spend that much money on a amp and not try the usual suspects... speakers, tubes, etc. though, so.... hmmm.

    Also, you really like the Custom 50, correct?
     

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