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The Dean Markley CD Series Club

Discussion in 'Amp Owners Clubs' started by Mr Perch, Feb 9, 2013.

  1. Mr Perch

    Mr Perch Tele-Afflicted

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    Another curious thing about the amp. The manual says that the "Vocal" switch only works on the "drive" channel, and it is indicated that way on the control panel. However, I can attest to the fact that it absolutely works on the clean channel as well. That's the switch I hit when I want to go to Jazz Heaven -- it's like a super warm, non-muddy bass reinforcement switch.
     
  2. Gnobuddy

    Gnobuddy Friend of Leo's

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    A plausible hypothesis, certainly. :D

    However the sea-sickness occurs even when the TV is turned off (but the sound continues to be heard through the monitor speakers I have hooked up to the DVD player).

    I have also experienced the same thing to a lesser degree when a car blaring loud music drove past me at speed; the pitch change due to the Doppler shift can temporarily "tweak" my hearing, a quite unpleasant sensation rather like momentarily losing ones balance while walking.

    IMO there is one thing well worth listening for in The Cure songs: the bass lines (the lyrics aren't always bad, either). One of my favorites is the bass line from "Love Song":


    -Gnobuddy
     
  3. Gnobuddy

    Gnobuddy Friend of Leo's

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    That switch does not appear on the old CD-120 schematic I found online. I think there may be several differences between your re-issue CD-30 and the original amp designs, judging by some of the things we've been discussing here.

    It would be nice to have a correct schematic - for me, to understand this amp better, and for you, so you can get it serviced some day if necessary. Have you tried contacting the manufacturer and asking for a service schematic?

    If this amp is as unpopular as it appears to be (for no good reason, sadly), it is likely to be out of production soon. I would ask for that schematic sooner rather than later.

    -Gnobuddy
     
  4. Mr Perch

    Mr Perch Tele-Afflicted

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    I removed the funny photos so as not to stray off-topic.
     
    Last edited: Feb 15, 2013
  5. Gnobuddy

    Gnobuddy Friend of Leo's

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    Not exactly a Cure fan, are you Mr. Perch? :D

    -Gnobuddy
     
  6. Mr Perch

    Mr Perch Tele-Afflicted

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    Well, I have now done a jazz gig and a blues gig with the amp. It is a remarkable amp. Gnobuddy, perhaps you could educate me on how sustain works. I had always assumed that sustain was a combination of heavy guitars and metal bridges, in conjunction with lots of gain/compression on an amp. I now must revise my conception, because my Tele, not a high-density instrument, seems to have endless sustain with this amp -- on the clean channel at low volume. I strum a chord using the neck pickup and jazz tone, and it sounds like a organ -- it lasts and lasts. Do you have a technical explanation for how this can be?
     
  7. Gnobuddy

    Gnobuddy Friend of Leo's

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    I'm not sure I have any useful ideas on what you're experiencing. Without changing the guitar itself, the only two ways I know of to increase sustain are to either put some (electronic) compression on the signal, or to get some feedback going between speaker and guitar.

    Is there perhaps a little more subtle distortion in your clean tone than you think? A little tube distortion could add some sustain. Or is there any chance that the very strong bass response of this amp is actually feeding back to the guitar enough to be giving you some sustain?

    Either way, it's good to hear you're happy with the amp!

    -Gnobuddy
     
  8. Mr Perch

    Mr Perch Tele-Afflicted

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    I probably erred by saying "endless," because it is not literally endless, just a long long time. What I described above doesn't feel like feedback - I am familiar with feedback, and I can get it with this amp easily using the "drive" channel, as I did intentionally at the gig the other night when we ended "Manic Depression."
     
  9. Mr Perch

    Mr Perch Tele-Afflicted

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    Gnobuddy, from your perusal of the old schematic, can you explain what the difference is between hitting the high, mid or low boost switches, and simply turning up the corresponding tone knobs?
     
  10. Gnobuddy

    Gnobuddy Friend of Leo's

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    Truthfully, the old Fender 3-knob tone stack is sufficiently complex in its operation that I don't fully understand it. The Dean Markley version is even more complex, and I think the only way I'd really get a handle on it is to run it through circuit simulation software (like LTSpice).

    Without having done that, all I've got is speculation. Perhaps the switches are there for quick and easy access to a different tone; you could flick one of those switches on or off partway through a song for an instant tonal shift, and go back to your previous setting with one more flick of the switch.

    Or perhaps the switches are there to augment and extend the range of the existing tone controls, like the "Bright" switch on many amps, which extends the range of the treble tone control to include even brighter tones.

    Overall I get the feeling that this amp was very much designed to provide the user with as much versatility as possible. The wider than usual tonal sweeps of the tone controls and additional tone switches seem to be part of this philosophy. In the end they give you lots of ways in which to tweak the basic sound of the amp.

    -Gnobuddy
     
  11. shmomas

    shmomas NEW MEMBER!

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    Hi there,

    So happy I found this thread...I love my Dean Markley CD-120.

    I have a question regarding the effects loop as well. Specifically, it doesn't seem to work as it should. When I use it there is a significant decrease in volume that doesn't seem to respond to turning up either the volume, gain/drive, or master knobs. This pretty much makes the effects loop useless to me. I was wondering, could the problem be with the preamp? I replaced the power amp tubes not too long ago, but I don't think the preamp tubes have been replaced for years. Any other ideas about what the problem might be?

    Thanks
     
  12. Mr Perch

    Mr Perch Tele-Afflicted

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    I found that I had to turn up the "return" knob on the effects loop in order to get the amp volume up where it ought to be. And, I had to do this regardless of whether the effect is engaged. This may be a design flaw.

    Just out of curiosity, where do you run the master volume on your amp? On my CD 30, I never get higher than "3" -- It has to have more than 30 watts. The idea of having a lot more power than that (120 watts advertised for the CD-120, and maybe more than that in reality) boggles my mind.
     
  13. Mr Perch

    Mr Perch Tele-Afflicted

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    BTW, I abandoned the effects loop. The only effect that I run is a true bypass Univibe, and I get better results running it between the guitar and the amp.
     
  14. Mr Perch

    Mr Perch Tele-Afflicted

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    I do note that with all three tone boost switches on, the amp is noticeably louder than with them off -- the tone gets fatter, too, like with a clean boost pedal. I don't see a similar increase in volume by boosting the tone knobs, although if I attenuate all three tone knobs, once I cross the number "1" the volume goes down to zero.
     
  15. Gnobuddy

    Gnobuddy Friend of Leo's

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    I'm bad at amp history, but I believe Marshall amps have that same characteristic.

    What I heard is that Jim Marshall's tech guy stole Fenders tone control circuit, but noticed that it caused a lot of signal loss when inserted into the circuit.

    This was not a big problem in a clean-voiced Fender amp, but it was a big headache in a Marshall amp designed to overdrive into rock tones. You can't have the tone control circuitry eating up precious gain.

    So Marshalls tech modified the Fender circuit a little, ending up with something with lower insertion loss (it doesn't kill the signal quite as much when the tone controls are set at normal positions). Somewhat paradoxically, his modification had the odd side-effect that if you turn all three tone knobs down to zero, no signal at all gets through the tone control circuit.

    As long as you don't accidentally do that during a performance in front of an audience, I guess it doesn't matter much!

    -Gnobuddy
     
  16. Mr Perch

    Mr Perch Tele-Afflicted

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    That's not too likely. As I continue experiment with the amp, I am inclined at this point to set all the tone knobs at 5, turn all three boost switches on, and leave it alone, controlling tone with my guitar knob should I switch pickups. This may be due to the unusual characteristics of my Bill&Becky L200 pups - they don't seem to take well to having one particular part of the EQ spectrum selectively boosted at the amp stage. The exception is when I play straight ahead jazz, I turn the bass boost on and not the others.

    Why do you think that the boost switches increase the volume?
     
  17. Gnobuddy

    Gnobuddy Friend of Leo's

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    Well, as far as I can tell, they each boost a broad range of frequencies. One boosts a range of midrange frequencies, probably a bit like a wah-wah pedal set to one position. The other appears to boost all frequencies above some starting frequency.

    Of course if you boost a good fraction of all the frequencies coming through the amp it's going to sound louder - it's like turning up four or five sliders on a graphic EQ pedal.

    It's interesting how one specific guitar and/or one set of pickups doesn't always get along with the EQ ("voicing") built into some particular amp. Tempted by a gorgeous-sounding YouTube demo of a Laney L5T-112 amp with a Yamaha Strat-like guitar, I tried one of those amps out with an ES-335 inspired semi-hollow guitar - and the combination sounded honky and midrangey and not very nice at all. Twiddling the available tone controls (bass, mid, treble, presence) didn't fix the issue, either.

    -Gnobuddy
     
  18. Mr Perch

    Mr Perch Tele-Afflicted

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    That's interesting -- back in the 70s I had a Peavey Classic with an overdrivable solid state pre-amp, and it really sounded like crap. Then one day I discovered that I could take a little battery-operated MXR 6 band graphic equalizer, put it between the guitar and the amp, crank up the midrange, and suddenly I had really nice clean overdrive.
     
  19. Gnobuddy

    Gnobuddy Friend of Leo's

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    I'm guessing that the midrange boost caused the amp to distort more on the middle frequencies and less on the (relatively weaker) high frequencies, so you got less of the harsh high-frequency "fizz" and more of the midrangey overdrive that sounds more musical (unless you're a drugged-out metalhead, in which case the harsher the better).

    I love having an EQ pedal between guitar and amp. It can do so many things for you - shape the tone, give you a gain boost, sound like a different set of pickups without the cost and hassles of a real pickup swap.

    It also works wonders on acoustic guitars with built-in piezo electronics. With an EQ pedal you can tame the harshness, change the tone of the guitar from deep and Martin-like to bright and Taylor-like, dial down any bass boom or midrange honk, and generally make one cheap acoustic guitar sound like about five different types of expensive ones. My el-cheapo Walmart acoustic guitar with the laminated (i.e. plywood) top can sound really sweet through the amp once I've EQ'd it to take away the bright "zing" and strengthen the weak bass. My Yamaha acoustic sounds great with no EQ, but using a graphic EQ lets me sweeten and finesse the tone to taste.

    I have a cheapo $30 Danelectro Fish-n-Chips 7-band EQ pedal I use for this sort of thing. That was surely one of the best thirty bucks I've spent on music gear!

    -Gnobuddy
     
  20. EdMan57

    EdMan57 Tele-Meister

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    I purchased a clean original '85 CD-30 a couple of years ago and it is indeed a very cool amp.My amp tech replaced some filter caps and installed some fresh JJ 6L6 power tubes.I also replaced the tired original Magnum speaker with a new Celestion MC-90 to excellent results.I recently had a chance to open up the amp's overdrive channel [both gain/volume at 2 o'clock,master cranked] a few months back and it really screamed,easily hanging with a friend's '69 Marshall 50 watt Plexi half stack.I was actually surprised how big and mean the CD-30 sounded when played loud.The amp's overdrive also seemed to sound more British the higher the master volume was set.Btw,played a re-issue CD-30 at NAMM and it sounded really close to my original,if maybe a bit stiffer and brighter [possibly much due to different speaker].



    Ed
     
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