How does Hot Rod Deville 410 really sound?

Discussion in 'Glowing Bottle Tube Amp Forum' started by anthrotony, Jul 22, 2019.

  1. anthrotony

    anthrotony Tele-Meister

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    For years I've been pretty happy with the sound of my Hot Rod Deville 410 (1998 USA model) by replacing the v1 with a 12AY7 (ECC83S) tube and v2 with a 12DW7 in V2, and using a volume box in the effects loop. This allowed me to play the clean volume around 7-8 for a little preamp breakup, and keep the overall SPL down to about 90db or so -- my personal sweet spot where the speakers are working and there's effective feedback between the guitar and the amp. But I'd never heard the amp with power amp saturation.

    I accidentally stumbled on to a long thread in the Marshall Forum (was not a regular browser there as I'm totally Fender-based) in which the author, @JohnH, described his journey to design and build a "perfect" attenuator with the simple goal to massively reduce the volume of powerful Marshall 50W amps but with negligible tone loss. He succeeded brilliantly, and in his thread, he shares his ideas and evolving schematics. I'd encourage anyone interested in attenuators to spend some time there, especially after about page 10, when he starts making significant progress with what he called Attenuator M. Please pay attention though to what John requests should you consider building your own (not for business purposes, for example).

    http://www.marshallforum.com/threads/simple-attenuators-design-and-testing.98285/

    So I built one and this thread will attempt to show just how well it works, and also try to demonstrate the real tonal capabilities of the Hot Rod Deville amp, which as all of us know, is generally either loved or loathed. Quick summary for those who don't want any detail: there is almost no perceptible tone loss at all caused by the attenuator, even when going down to the maximum level of attenuation of -31.5db which is true bedroom level; obviously at bedroom level the speakers aren't really pushing much air and isn't my preference; the HRDv is excellent for clean tones and as a pedal platform, particularly with Fender guitars (no surprises), and is pretty decent for classic rock tones but not exceptional (without pedals). Just for fun, I"ll also add some thoughts on the BassBreaker 15 as a comparison.
     
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  2. anthrotony

    anthrotony Tele-Meister

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    So here's my attenuator.

    attenuator m tony-enclosure.jpg attenuator m tony-inside.jpg

    I'm calling it the AmpCranker and I'll add a graphic design to the enclosure top between those holes just as soon as I can figure out how to transfer the design to a black finished aluminium case!

    attenuator top artwork BW FINAL black background.png

    The jack socket on the left of the case is the speaker out (i.e., from the output transformer), and the one on the right side is to connect to the speaker itself. The switches, left to right are as follows:

    1. Full Bypass or -7db - this is the standard inductive attenuation
    2. Bypass or -3.5db
    3. Bypass or -7db
    4. Bypass or -14db

    The attenuation switches can be used in any order (apart from the first full bypass one), giving attenuation from -7db to -31.5db in -3.5db increments.
     
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  3. anthrotony

    anthrotony Tele-Meister

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    So just for a starting point, I wanted to hear what the HRDv sounded like at a solid volume of 6.5 on the clean channel. Treble is 8, Bass 5, Mids 6, Presence 8. A little delay and phase. This is where breakup just begins if the strings are attacked hard. G&L Legacy guitar. "Shine On-ish", greatly simplified and abbreviated, and still with the inevitable mistakes that I make as soon as I hit the record button ;).

    I'm not set up right now with a proper mic and interface, so for all recordings, I used my Sony PCM-M10 which is a digital recorder I usually use for recording nature and wildlife samples. Brilliant little thing. Placed about 20cm in front of the 4x10 speaker cab midway between the two right speakers. The guitar part is saved onto a Boss Looper pedal that I can then play back with different amps and levels of attenuation to maintain exactly the same source signal.

    This particular recording was done with the attenuator at -14db, giving a room SPL of 80-95db depending on the guitar dynamics. I would love to have been able to start with no attenuation but that would have been window-shatteringly loud in my cramped music space! Again, apologies for the mistakes...



    And this is the same sample played through the BassBreaker 15 using a WGS ET65 speaker. -7db attenuation. Settings: Clean structure, MV 8, Gain 5.5, tone controls all at 6. Again, room SPL was very similar in level.



    I'd be very interested to hear what people think of the difference in tonality! The BassBreaker series are marketed as being modelled on the Bassman amps of yore, but many people point out that the BB15 is a sort of Marshall-esque amp. I'm not sure. I've been trying to like it for a long time, but am only now beginning to enjoy it given that I can really crank the amp (not playing gigs right now).
     
  4. hotrodkid

    hotrodkid Tele-Holic

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    I thought the HRD sounded better. Probably because I heard more midrange and the notes sounded more solid compared to the Bassbreaker.

    I had an early version of the 2-12 HRD in tweed which somebody lacquered and reliced. It was so cool looking but waaaaaaay to loud. Insane touchy taper on the volume pot made it difficult to tame. Sounds like this would of been the solution.
     
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  5. anthrotony

    anthrotony Tele-Meister

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    Obviously, the next step was to see what the HRDv sounded like dimed. So, here's a short Cocaine riff played through the clean channel with volume at 12. Tone controls as earlier. The loop starts with -14db of attenuation and then each iteration adds -3.5db of attenuation, so respectively -17.5db, -21db, -24.5db, -28db, and -31.5db. The first loop (loudest) was registering around 95db of SPL, and with full attenuation I was reading in the mid-60db level. Very easily bedroom levels but with no air being pushed, not my choice!



    To make sense of this I then used Audacity to normalise each loop to -1db so that the perceived volume of each remains the same, which is a bit easier to use to determine any tone differences. Remember that any actual differences will also reflect the room recording technique with much less driven speakers so should not automatically be attributed to the attenuator itself.



    I hope that these samples are helpful to those who are interested in how good an attenuator can actually be, as well as how good or bad a Hot Rod Deville really sounds!!!

    I'll continue to offer other audio samples for better overall reference.
     
  6. anthrotony

    anthrotony Tele-Meister

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    Last edited: Jul 23, 2019
  7. anthrotony

    anthrotony Tele-Meister

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    I agree though a few friends preferred the BassBreaker sound. Definitely a subjective and very personal thing! Also, the 10" speaker are clearly more punchy and focussed than the ET-65 12" i'm using on the BassBreaker. Right now I'm experimenting with playing the BB15 through the 410 cab and so far I think I'm enjoying a little more...

    I'm still confused as to why the Cocaine audio samples aren't showing when I look at the thread. When I try to edit the post they show clearly that they are there, exactly the same as for the Shine On-ish post. I'll work on it as these recordings specifically try to show the tone difference of higher and higher levels of speaker attenuation.

    That would have been a nice looking amp. And probably really great sounding too except for the overwhelming volume :) Oh, using a 12AY7 in v1 really tames that volume taper...
     
  8. anthrotony

    anthrotony Tele-Meister

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    Last edited: Jul 23, 2019
  9. anthrotony

    anthrotony Tele-Meister

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    Last edited: Jul 23, 2019
  10. Wildcard_35

    Wildcard_35 Tele-Meister

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    That's a really nice looking attenuator box you have built there. I think the HRD might sound a little better to my ears, but it is a song that tends to be (in my mind) a song that just sounds really good clean. Love when the phaser kicks in for the "dun dun da DUN" part. I also dig how you used a looper to record both parts to actually show how each amp sounds with the exact same thing played through it.
     
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  11. anthrotony

    anthrotony Tele-Meister

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    Thanks, but all real credit goes to JohnH who did all the real work -- I just interpreted his design and adapted it to the components I was able to acquire from aliexpress for a really good low overall price :)

    But for sure, Gilmour's guitar style really needs super warm and clean tones, which the HRDv does pretty well, whereas the BB15 has a different take on "clean". It's nice, but I've not been able to really bond with it -- so I'm currently about to build a 5e3 from scratch to hopefully give me an alternative tone that I will be totally happy with. Although now that I've heard this attenuator in action, I'm actually considering skipping the 5e3 and building one of the larger tweed amps that offer greater headroom while still delivering that lovely Tweed clean (as well as the grind of course).

    The looper was important to me for this and all my other tests because I'm all too aware that every time I play my guitar, I sound different depending on my mood, fatigue, and of course, just my picking dynamics. Now if I can figure out why all of my subsequent attempts to embed SoundCloud clips isn't working despite using exactly the same method as for the Shine audio, I'll post some examples of what the HRDv sounds like with tube saturation!

    Thanks for your kind comments!
     
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  12. anthrotony

    anthrotony Tele-Meister

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    Cocaine attenuated -

    Cocaine attenuated and normalised -
     
  13. anthrotony

    anthrotony Tele-Meister

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    Wow, not sure what I did differently but it worked this time! Sorry for the multiple in-between posts!

    Given that the Hot Rods are thought of more as blues or classic rock amps, and given that so many people say they really dislike the overdrive, I recorded a very much abbreviated "Alright Now" using my ES-335 (never owned a LP). The MV was at 12, dimed of course, and I played the loop through the drive channel where the Drive level was incremented in graduations from 2, 4, 6, 8, 10, and 12. After each segment recording, I engaged the More Drive, so Drive and More Drive alternate throughout the recording. The attenuator was set at -17.5db, which was as loud as I could manage in my small music space (pushing around 100db in SPL). Obviously it would have been better if I could have started with no attenuation, but, reality prevailed! Finally, to demonstrate the attenuator's capabilities, after recording the loop with More Drive and MV both dimed on 12, I re-recorded the loop with those settings but with attenuation being increased by -3.5db each time, so -21db, -24.5db, -28db, and -31.5db. I left the recording un-normalised so that the difference in perceived volume is apparent throughout. I can always normalise each of the final segments if anyone desires. Oh, even though the riff is very abbreviated, this is a long recording as there's so much going on!

    Enjoy - and sorry for the sloppiness!



    And just for fun, I replayed a simple riff through my BB15 (ie not the loop) on the Medium Gain channel -- Gain at 5.5, MV at 8 out of 10, Tone controls all at 6. For this version I was able to play with just -7db attenuation. I'm offering it simply as a way to hear clearly the differences between HotRod-type amp overdrive and the BB15's own version.

     
  14. kaludjerko

    kaludjerko Tele-Meister

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    Hi, thanks for posting this, very interesting topic. Still reading and listening to samples, but have one question in the meantime. :)
    How do you measure room SPL? Is your Sony recorder giving you this value or you have separate unit to measure SPL?
     
  15. anthrotony

    anthrotony Tele-Meister

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    I'm using an iPhone app -- NIOSH SLM -- which is tested to within +/- 1db. It's free and very easy to use. However, I'm providing just an estimated average of the level rather than peaks or lows with the phone right about 1m directly in front of the speakers. I realise it's certainly not totally accurate but is a reasonable guide. The HRDv produces around 118db at 60W according to various internet sources, and this seems to be correct as far as my own measurements with attenuation are concerned.

    Hope this helps :)
     
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  16. Musekatcher

    Musekatcher Tele-Afflicted

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    JohnH really gets into his project. He's headed into the right territory with his DSP comparisons (digital signal processing). There may be a few errors in his measurements though. Without the room contribution, he risks measuring some of the cancellation and amplification at various frequencies, so that his measured frequency responses aren't correct. Comb filtering error is common when making these kinds of sound meter measurements in a small household room.

    I like that he did the DSP math to look at the delta or differences at each frequency (the green line above the two plots), but again if the FR's weren't correct, neither will be the difference calc. Finally, he didn't look at any phase shifting, rms values, or other math values available.

    I'd like to see someone's serious study of the key characteristics important to amp tone. I'd start with the frequency response, and phase content as two important values, and there maybe others. And it will get really complicated, because the response will be heavily dependent on the initial frequency content, considering how much coupling occurs - an example is how you can overdrive the highs by quick-picking harder near the bridge, or how you can overdrive the lows by strumming wide but softly near the neck - you'll get two different distortions, similar volumes, on the same string without changing any settings. Another example of the coupling effects, is turning down the bass, only to have the mids get louder.

    Finally, once you identify and measure all the important values, you can then build a frequency response function (FRF) that gives you a mathematical expression that converts the input signal to the output signal. The input is the guitar signal, the output is the distortion signal supplied to the amp section or even the speaker. I think this is how modelling is done? Once you get an FRF, someone can design an LRC circuit to apply the FRF and give you a scalable replica of the tone you want - scalable to lower volumes is the goal. Which, gets even more complicated, because the FRF will be dependent also on the input volume - you'll need another order of FRFs to curve fit together if you plan to match more than one input volume.

    At any rate, attempting to characterize the desired tone at volumes, so you can replicated it at lower volumes sounds like the work being done with IR's? IR's look like another form of digital FRFs (just software, no electronics involved). I think an attenuator is a mechanical solid state version? If so, a really accurate, scalable attenuator sounds like a really involved project that might take a long time to figure out and crack, College thesis topic? Or did I just describe a modelling amp?

    In the meantime, a custom designed attenuator that at least hits a similar scalable tone at one input/output range sounds like a good project, achievable, and useful, and maybe more successful than buying a commercial product that tries to be all to all, which doesn't seem possible when you understand what all is going on when you crank an amp.
     
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  17. anthrotony

    anthrotony Tele-Meister

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    Brilliant post but way beyond my level of understanding, so I'm taking you totally on face value :) Might I suggest that you chat directly with JohnH over on the MarshallForum? I'm sure he'd be delighted for the discussion!

    While I can understand at least some of what you are talking about, to me the most important aspects of general purpose attenuation (for use in the home, rehearsal studio, or in gig situations where otherwise we can't get down to the desired volume levels), is that the amp "feels" like it should taking into account some of those dynamics you're talking about, and that the resulting sound coming from the speakers is good by my own very high standards (like most guitarists and musicians I guess). So in my case, the fact that I can push the amp to get the beginnings of guitar feedback on each note within nice melodic lines (I'm thinking for example of some Santana tunes), and that I can still control this from the guitar while listening to a very pleasing tone, is super important. Is it absolutely tone-loss free? As you say, that would require some serious objective testing! But is it close enough that I don't feel that I'm sacrificing anything? Absolutely. So I'd say that this attenuator is THAT good. And the fact that it can be build quickly for a very reasonable cash investment makes it a really worthwhile project. I can also say that I've tried some of the commercial attenuators in music shops, but the tone loss was quickly apparent. So that's a plus for this one!

    Sadly, I'm not a great guitarist to be able to really "show off" the amp or the attenuator, and that's why I'm keeping the audio samples fairly simple. The Hot Rod amps are often used for blues tones and rarely for hard rock (although with the right pedals that works ok), so I'll post a few other samples that reflect blues sounds in real life situations with no pedals, that's to say, clean or edge-of-breakup and try to contrast this with either a mild power tube overdrive or even with the clean channel dimed. So far, I feel that this is still the best way to get the best tones out of my amp. That said, and with my particular preamp tube setup, I can at least set my tone controls for a compromrise "best" in order to switch between Clean and Drive channels (this is often cited as a problem with this amp, in that we can lose a lot of "tone" when we do so). I think this gives very usable tones with the attenuator while keeping the volume levels down to more or less "normal" gig levels (say around 100-105db???).

    Anyway, I really hope that this helps others -- that's my only real goal. Well, that and to play brilliantly with some other real, brilliant musicians also ;)
     
  18. anthrotony

    anthrotony Tele-Meister

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    Here's an SRV-inspired riff, "Mary Lambish". Using my G&L Legacy. Attenuation at -17.5db. The Clean volume is first set to 7.5 which is where I just begin to get some breakup, and then my loop plays through the same channel with the volume dimed at 12. I have to say that this ain't no bassman, and I really don't think the amp is meant to be fully dimed!

     
  19. anthrotony

    anthrotony Tele-Meister

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    And staying with a Stevie style, this is "SRV-ish", recorded first at Clean Volume at 5.5 (so really clean) and then at Clean Volume at 9.



    As soon as I make some more time, I'd like to record some clean channel pieces with some pedals, probably with the Clean Volume around 8-9 which seems to be sweet spot with the G&L. I'd also like to switch out the preamp tubes and replace them with 12AX7s to see what that does.

    If anyone has any particular suggestions please don't hesitate to let me know. Or if you want to send me a short MP3 of your own, I can always run that into the amp at suggested settings! Why not? ;)
     
  20. anthrotony

    anthrotony Tele-Meister

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    One more for now. A simple minor blues played on the G&L Legacy. Recorded into a Boss Looper pedal, then played on the Clean Channel with volume at 8, then replayed through the Drive Channel with MV at 8 and Gain at 6, finally though the More Drive Channel with the same settings. Attenuation at -17.5db

     
    Last edited: Jul 23, 2019
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