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PEAVEY Mark III vs Mark IV

Discussion in 'Amps and Cabs [BG]' started by RobbieNuke, Dec 24, 2014.


  1. RobbieNuke

    RobbieNuke

    Jan 22, 2008
    Baltimore
    My main instrument is electric bass, but I play a bit of keyboards as well in a cover band. Most of the time I run my keyboard rig (Hammond SK-1 and Moog Minitaur) the through the PA. Occasionally, however, I need to run the keyboard rig through a backline amp.

    I was contemplating acquiring a Peavey Mk III or Mk IV amp mostly because they are high-powered 2-channel amps which would allow me to backline my electric bass and keyboard rig using only one amp/cabinet.

    The two pre-amp and and single power amp circuits of these amps seem identical (with the exception of the bi-amp crossover and compressor features of the Mk IV).

    I was looking for opinions from anyone who has had experience with either or both of these amps. I'm not into bi-amping so that particular feature of the Mk IV doesn't matter to me (but a nice option to consider in the future). However the compressor circuit seems interesting since there is occasional output difference when switching keyboard patches.

    • Is the compression circuit 'always on' or can it be bypassed?
    • How does the tone of the power amp section compare between the Mk III and Mk IV?
    • Remote footswitch: Does using the standard Peavey remote footswitch cause any noise (i.e. clicks/pops/etc) when actuating the push button switches?
    • Any quality/reliability/service issues between the Mk III and Mk IV?
    NOTE: Please refrain from suggesting other bass amps or PA powered mixers (I have several of each already). I am interested in feedback/opinions of the character of these two vintage Peavey bass amps only. Thanks.
     
    Last edited: Dec 24, 2014
  2. LowEZ

    LowEZ Supporting Member

    Mar 29, 2011
    Central NJ
    DDT is always on but can be defeated internally quite easily.
    The tone is comparable.
    No idea regarding the footswitches, never used them.
    Mine never required any servicing, typical Peavey.
     
  3. diamondsplit

    diamondsplit

    Jan 13, 2012
    N.J
    markIV is much better
     
    Giffro likes this.
  4. RobbieNuke

    RobbieNuke

    Jan 22, 2008
    Baltimore
    Well THAT is an in depth response (LOL)! Care to elaborate on the reason(s) why it's MUCH better, not just a little bit or slightly better?
     
  5. diamondsplit

    diamondsplit

    Jan 13, 2012
    N.J
    Yes MarkIV was a better sounding amp it had more features you had more tone control. I had the opportunity to buy Mark III for 50 bucks and i had all weekend to mess around with it and did not have the punch and the sound quality was better. I had a Fire Bass 700 and Bam modeling head. I got rid of both of them in favor of the markIV and I remember when they first came out they were the best head for the money Peavy made a big step forward and the Mark VI and VII are supposed to great. I played a Tour 450 and that had to be the worst. To this day the markIV is considered a good amp. I have played great Amps SVT Pro II Eden WT 1205 WT 800 Markbass TA500 and I have an AMP 420 and that kicks but. Its a Thunderfunk with less watts and the Thunder Funk is one of the best Amps on the market
     
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  6. RobbieNuke

    RobbieNuke

    Jan 22, 2008
    Baltimore
    OK, a little more digging and it seems the Mk III heads have a 400B power amp (without heat-sink) and the Mk IV has a 400BH power amp (with a very large heat sink). Both models have the same impedance/power ratings. Owners Manuals are copyrighted 1979 for Mk III and 1982 for Mk IV making the Mk IV a slightly newer version (and probably slightly more reliable since the assembly line folk would have had that much more experience in manufacturing them as well as any upgraded engineering revisions along the way).

    I erroneously noted in my first post that only the Mk IV had the bi-amp and DDT compressor. The fact is that the Mk III and Mk IV have both of these features. However, the Mk III has a compressor bypass switch where the Mk IV does not. These were two items were replaced with a bright switch on each channel in the Mk IV.

    So, I seem to be leaning more towards the Mk IV at this point with a more robust heat sink and Bright switches; everything else seems to be the same between these amps. The Compressor bypass switch (a feature I do like) can probably be easily modded into the circuit.
     
  7. I bought a MKIV in 1985 here in oz and at the time it was a ''industry standard'' bass amp..ie just all the bass players in top bands in Oz used them in the 80s 90s including myself..even tho' I've upgraded to a GB Streamliner and GK Neo212 I can't bring myself to get rid of my MKIV with the sliver stripe 115B cab..great amp..made to last..you cant beat the twin channels with the para mid eq and graphic

    Leslie
     
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  8. LowEZ

    LowEZ Supporting Member

    Mar 29, 2011
    Central NJ
    If you pull the chassis you will find a 2-pin loop connector on the PCB that looks something like my MS Paint rendering below. This is the DDT compression enable/disable loop. The function is enabled when looped, disabled when open. Wire it to a simple SPST switch and you've got the DDT bypass switch missing on the MK IV.

    ddtloop2.jpg
     
    Last edited: Dec 29, 2014
    AlexanderB, Giffro, quickfix and 3 others like this.
  9. RobbieNuke

    RobbieNuke

    Jan 22, 2008
    Baltimore
    Great tech tip! Thanks!
     
    PawleeP and lesliegl like this.
  10. LowEZ

    LowEZ Supporting Member

    Mar 29, 2011
    Central NJ
    Disclaimer:
    Just be careful. Back in the day I fried an 18" Black Widow with a Mark IV with DDT disabled trying to keep up with an extremely loud band. DDT is there for a reason. ;)
     
    RobbieNuke likes this.
  11. RobbieNuke

    RobbieNuke

    Jan 22, 2008
    Baltimore
    Totally agree with your caution warning! Most one knob/one switch compressors are really just limiters... great for speaker protection (especially us bass players). I have one on an Ampeg B-1 combo. However, I generally don't like the effect it has on my tone when I'm up there 'on the edge' getting a bit of amp AND speaker distortion (when playing bass).

    But since this amp would be pulling double duty as both an electric bass AND keyboard/synth bass amp the feature would probably be left on.
     
    LowEZ likes this.
  12. Scottkarch

    Scottkarch

    Sep 11, 2012
    Chicago
    I have a Peavey MKIII. It was my first amp after a Peavey TNT100. It must be a later model Bass MKIII since it has the same giant aluminum heatsink as the MKIV. It works well to wrap the power cable around. It looks like this.

    peav-xr600c-mixer-amp3.jpg

    And you're right.. It has the DDT compressor bypass switch and LED, as well as the crossover. I have a Black Widow 115 and a 210TX cab. I have a 3rd party footswitch.. lost mine years ago. I havent noticed any switch noise when changing or combining channels. I actually like the tone of my MkIII. Plenty punchy through a 115 BW. Just too heavy. But I am hesitant to get rid of it.. I have a feeling it will outlive my light class D amps. In my opinion, if you got a good price on a Mk III, I think its a nice amp and would probably be fine. Maybe the MkIV is better, I've never heard one. I assumed they were near identical.
     
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  13. I wouldn't worry about the DDT circuit at all. It isn't a compressor as much as a limiter and you don't hear it working, just the occasional flash when it kicks in. You may reach that point more often with your volume/low-end pumping hard and if you expect or need proper compression I would suggest using a pedal.
     
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  14. RobbieNuke

    RobbieNuke

    Jan 22, 2008
    Baltimore
    I have a compressor (ART Levalar) on my pedal board for my bass.

    I've never owned any PEAVEY amps/speakers, but have gigged/jammed thru several over the years. Did not spend enough time with any to give a proper evaluation, but they seemed adequate for the situation. There are a ton of Peavey amps in the basements in my town (Baltimore), but seldom seen on-stage of the rock night clubs. They are just not considered the proper fashion statement.

    It seemed that years ago (starting in the 60's) almost ALL amps had two channels. Now, there are very few guitar amps with 2 discreet channels and NO bass amps (except the SVT Classic Reissue).
     
  15. RobbieNuke

    RobbieNuke

    Jan 22, 2008
    Baltimore
    WOW! Nice transition model. Like you, I also assume they are identical except for the differences listed above.
     
  16. For what I assume you'll be paying for either head you don't have much to lose by trying. I had a MKIII or IV (too long ago to be sure which) and used a TNT160 for years after. Tone-wise the best description I can think of is CLEAN. Think transistor clean with a flat response. Not organic, chewy, warm or any other silly description. Just an even, uncoloured tone of your instrument. Great for keys through 15's. The EQ's on these heads are powerful - especially the older parametric versions.
     
    Last edited: Dec 29, 2014
    deathness, RobbieNuke and Scottkarch like this.
  17. Basshappi

    Basshappi

    Feb 12, 2007
    Tucson,AZ
    I agree. The SS "Peavey Tone" is clean, you get the natural tone of your bass and whatever coloration that your cabs impart.
    I have a MkIV I bought new back in '82. I have used it with every cab config there is as well as bi-amped and it it has even served as a monitor power amp on more than one occasion.
    Great amp!
     
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  18. LowEZ

    LowEZ Supporting Member

    Mar 29, 2011
    Central NJ
    To each his own. DDT is rather transparent if you play a P bass with flats but if you're into more aggressive tones, it's an attack killer. Personally, I much preferred the sound of my Mark IV at the verge of, and into clipping than with DDT activated. The option is there, that's all I wanted to point out.
     
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  19. I've been playing a Mark IV for years. I love this amp.

    I play through a Roland GR-55 so I have synth patches playing simultaneously with the bass tone.

    There's an incredible amount of control for tone. I've had mine serviced but the previous owner did not take great care of it.

    I never notice the compressor when it kicks in unless I'm looking at the head and actually see the light blink.

    I've never noticed any noise with the foot switch, although I almost never use it. All my controls are on my synth pickup.

    image.jpg
     
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  20. RobbieNuke

    RobbieNuke

    Jan 22, 2008
    Baltimore
    Tell me more about the footswitch. Can you post a close-up of the labels? Do you have a schematic? These seem to be hard to locate.
    I'm debating on repairing my vintage Acoustic 320 amp or buying a Peavey Mk III or Mark IV.
     
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