Based on its merits one would expect it to be selling much better than some more popular (but less well thought-out) amps from more famous amp manufacturers with longer histories. IMHO this was designed by a smart and savvy engineer (or team of engineers). The more I look at this schematic, the more it strikes me as a solid, well thought out design. In other words, it looks like you can use "Volume" to set the clean volume, "Drive" to set the amount of preamp distortion, and "Gain" to balance your clean and dirt channel levels the way you want them.Īs usual you can use the "Master" knob to set the amount of overall volume and/or overdrive the power amp section to your taste. It looks to me like it's intended to let you set the balance between clean and dirt channels. It controls how much signal goes from the dirt channel to the power amp section. "Gain", on the other hand, is basically a master volume for the dirt channel only. Turning it up will overdrive V2 (one of the 12AX7's), and give you some preamp distortion. "Drive" controls how strong a signal goes into the preamp tubes in the dirt channel. I'm sure there will be new things to learn once I can bring the master volume up from "1" and get those main power tubes cooking a little.Ĭlick to expand.You're exactly right. On Saturday the amp will make the journey from my apartment to the rehearsal studio, and I'll have more to say then. When I use the overdrive channel, I hit the Bright and Mid Boost switches. This amp has a very deep and resonant bass response with the "voicing" switch on, but also you can turn it off if you want to scorch a little without getting murky. The clean channel is very Fenderish, but has more depth and nuance to it than on my SCXD. I also like being able to vary the gain on the clean channel - cranking the gain on that channel produces a good blues tone. After having to constantly fiddle with the volumes on the SCXD, I find this convenient. The other thing I've noticed is that the master volume controls the whole amp, and you can change the gain on either channel without causing a big change in the end product volume. I'm looking forward to hearing more as you continue to form your opinions about this amp.Īll the tone controls are shared by both channels. It sounds as though it has cleans as beautiful as a Princeton, and at the same time has much better (meatier, warmer, more musical) overdriven sounds than most Fender amps. The Dean Markley amps use beam tetrode output tubes, like most of the Fender amps, so that is another way in which they are likely to have a clean tone that resembles those signature Fender cleans. Pentodes on the other hand produce quite a lot of third harmonic distortion, which tends to sound growly or biting.
Since the Dean Markley amps have a similar tone control circuit, these amps will have a similar mid-frequency notch.įender amps also seem to have favoured beam power tetrodes for the output tubes rather than the pentodes used in European designs, and it turns out the two types of tubes tend to have different sounds: beam tetrodes produce a lot more second harmonic distortion (which usually sounds warm or shimmering), but very little third harmonic distortion. The CD 120 schematic shows one common shared set of tone controls between clean and drive channels - is that the case for your amp? No independent bass, mid, treble controls for the two channels?Ĭlick to expand.I believe part of what we have all come to recognize as a good clean tone is a characteristic mid-frequency notch that Fender designed into his tone control circuitry, and which we have all heard on thousands of era-defining songs. I don't fully understand why the Dean Markley design is so much more effective than the Fender design, probably because I don't fully understand the Fender tone stack design either. The tone control circuitry looks superficially like the Fender design, but with a few changes, including the addition of those "mid boost" and "bright" switches. The CD 120 schematic also shows "mid boost" and "bright" switches in the clean channel. In the rolled-off position it appears to reduce frequencies below 340 Hz.
In one position the voicing switch rolls off the bass, in the other position you have a flat frequency response.
The CD 120 schematics I found do show an "overdrive voicing" switch, but it's in the drive channel, not the clean one.
#Dean markly cd40 series
I also found references to the fact that all three amps in the CD series shared a lot of their circuit design. I couldn't find any schematics for the CD 30 or CD 60, but did find some hand-drawn schematics for the CD 120.
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