The Dean Markley CD Series Club

[Mr Perch]

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.

I'm slightly confused here -- is it possible that you meant it sounds more British with the "drive" knob set higher? From what you wrote, it seems to be saying that you turned the "drive" down to 2 and just made the amp louder with a low degree of overdrive, which I thought might be a mistake.

 

[EdMan57]

Mr Perch,I meant the gain/drive was set to 2 o'clock,a couple of notches above half-way.With the master volume on full,the power tubes added output tube saturation,really allowing the presence control to add some extra British flavored bite.I find that the gain/drive controls much above 2 o'clock add mostly compression to the higher gain tones,especially when the master is near max.


Ed

 

[Mr Perch]

Dang -- and you can still hear things after that? I put the clean channel on 7, the "drive" on 6 (5 is half-way) and the gain for the drive channel at 8. With those settings, I don't dare put the master volume above 3.

 

[EdMan57]

Yeah,the amps were quite loud.We were playing in a rather large insolated studio rehearsal room with a high ceiling.Btw,the only amps that I have that are obviously louder than my CD-30 are my Mesa/Boogie MKIIC+ [60 watt] and Krank Nineteen80 [80 watt] heads.Volume wise,my CD-30 easily hangs with my Bedrock 651 1-12" combo [50 watt] and Randall RD50 head [50 watt].


Ed

 

[Mr Perch]

Once I had an Ampeg 100 watt tube head, and I learned that I could remove 2 of the 4 power amp tubes and reduce the wattage, making it possible to drive the thing a bit without going deaf. I wonder if it might be possible to remove one of the CD30's 2 power stage tubes? Or do those tubes always come in sets of two?

 

[Gnobuddy]

I wonder if it might be possible to remove one of the CD30's 2 power stage tubes?

Sorry, no, you can't do that without damaging the amp.

Just about any amp more powerful than a Champ has what's called a push-pull output stage (also called Class AB). In this type of circuit, a pair of tubes divides up the load between them - one handles all the positive half-cycles of the AC waveform from your guitar, the other handles all the negative half-cycles. Your CD30 most certainly has a push-pull output stage.

If you removed one tube from a push-pull output pair, you'd only get half of your guitar signal - it would sound extremely distorted. Worse, there is a very good chance that your amps output transformer would be damaged - and if it fails, it might very well take out the output tube(s) and other components with it.

A very crude analogy is the ancient two-person push-pull saw used to fell trees. If one person walked away, the other could only pull the saw towards himself, he could not push it back without buckling and breaking the blade. Similarly, one tube in a push-pull stage by itself can only "pull" your guitar signal, not "push" it. That part is up to the second tube.

Your old amp with four output tubes is crudely analagous to a four-person push-pull saw, with two people pulling on each end. If one person from each end walked away, the remaining two could still operate the saw, albeit with less power.

And yes, if both people from one end of the saw walked away it would once again be render the saw nonfunctional - so when you remove two of the four output tubes from an amp, you have to know which two are okay to remove. One has to be one of the "push" tubes, the other one of the "pull" tubes. Otherwise you invite the expensive magic smoke to leave the amp.

If you're wondering how the Champ (and similar small amps) manages it with only one output tube, the analogy is attaching a powerful return spring to one end of the two-person saw. Now a single person on the other end can pull it towards himself, and let the spring take care of the return stroke.

The downside, obviously is that the poor guy has to pull quite hard on the saw at all times, even to keep it standing still in one spot. Very inefficient, and leaves the poor guy hot and sweating in a short time. Exactly like the electronic version, which is called a Class A output stage, and also runs hot and inefficient.

-Gnobuddy

 

[Mr Perch]

That's what I suspected. No worries -- the amp still sounds great with the master volume on 3.

 

[Mr Perch]

My CD30 developed a problem and the dealer is having it fixed. In the meantime, he gave me a CD60 as a loaner -- boy howdy, that thing is way too loud. I jammed with a bass and drums and I kept the master volume at "1".

 

[Mr Perch]

My CD30 is up and running, and I've been gigging with it, both in a jazz duo with an upright bassist, and with my blues 'n' soul band. I'm still experimenting with the settings -- although it has no modeling or other gizmos, there are a lot of tones in it to experiment with, especially in fine tuning the "drive" channel settings. A tiny change in the the amount of gain makes a huge difference, and everything is slightly different at gigging vs. living room volume. I might post some videos in the near future.

 

[Mr Perch]

Are there any other Markley tube amp owners here who can share insights on how to get the best tones, using all the gain and tone capabilities of the amp?

 

[Gary Mitchell]

Two of the best amps I ever own were a, Dean Markley Signature Series 120 watt all tube rack mount head and a CD 60 combo. I on both of them in the 90s when I was playing Christain Metal. The head was awesome would blow away a Marshall, and they were not cheap. I can't remember the name but they were made in a little town in Kansas back then. I lived in Eldorado Ks at the time. I got both of them used but they were mint condition. I used a 212 Boogie cab loaded with EVs with the head and a Jackson USA Soloist neck tru with SA/SA/81 EMGs that was the good old days. 2 amps I good kick myself for letting go.

 

[Mr Perch]

I'm not a metal player -- I play blues, jazz and soul. I've got excellent clean tones dialed in on my CD30. I'm still experimenting to find the best Robben Ford-type tones using the drive channel. I have found that it's easy to go overboard on the gain and midrange, which produces an overly harsh sound. I'm going now with the high and low boost switches on, but not the mids, and the dirt up to 4-5.

 

[Mr Perch]

I made a demo video for the CD30:

 

[Mr Perch]

I know it's just a matter of time. The ranks of the Dean Markley CD Series club will swell, as more people catch on to the awesome coolness of these amps.

 

[EdMan57]

^^^^^ I agree.I do think that the line would be more successful if Dean Markley offered the CD-30/CD-60 in head form and also in black.


:idea:




Ed

 

[Mr Perch]

They need to make a CD20, as well. These amps seem to be a great deal more powerful than they need to be, and more powerful than their rated wattage. I wrote to DM and they told me a less powerful version was in the works.

 

[EdMan57]

...I wrote to DM and they told me a less powerful version was in the works...

Cool.Hopefully they use 6V6 power tubes instead of the more trendy EL84.



Ed

 

[kvia12]

Hi all,

I've got a 1980's model CD-60 that I've been playing for about a year. All of a sudden the clean channel has stopped working. On clean settings, I get a TINY amount of volume through the speaker (so quiet I can barely hear it) and it is heavily distorted. On distorted settings, amp is fine and works as it always had.

Any advice on what the culprit could be? I am comfortable with electronics repair, but I have no experience diagnosing problems in an amplifier. Any help would be much appreciated.

Thanks,
Luke

 

[Mr Perch]

I had a similar problem. Check your 3 preamp tubes. It sounds, from what you are saying, that the amp works normally using the drive channel? If so, I would bet that you need to replace a preamp tube. It may even be that you simply need to clean the socket, by removing the tube, spraying the prongs with contact cleaner, and then working them slowly (and carefully, so as not to bend them) in and out of the socket. But if the tubes are old, a replacement is probably in order.

 

[Gnobuddy]

I wrote to DM and they told me a less powerful version was in the works.

Interesting, so Dean Markley Corp is still hanging in there and trying to get these amps to fly? I'd sorta assumed that they might have given up by now, given the deafening silence all over the Internet around this line of amps.

Not that I think the lack of attention is deserved, mind you. But we all know the public can be fickle and good products often die undeserving deaths. I still miss the best PC operating system I've ever used, the one hardly anybody seems to have ever heard of, the BeOS.

-Gnobuddy