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Taming the beast

Discussion in 'Amps and Cabs [BG]' started by Mark Andrew, Jan 9, 2019.


  1. As a big fan of heavy valve amps I reimbarked on an all valve journey in 2016 continuing from my Marshall 2001 experiences to a Peavey classic 400. Don't get me wrong I use class D and other solid state amps regularly and on many fronts prefer them. However nothing makes me smile more than pulling out the big guns and snarling allong. However the brute force of the 2001 was what made me take a rest from valves in 94/5 and the brute force of the classic is proving likewise difficult to tame. A HPF has given my new faital pro drivers an easier time and good use of the resonance settings and taking it easy on the bass settings makes for a nice snarly loud rig when I have the energy to lift it. But when switching to the mini max or the mkviiixp I appear to get more usable headroom. Out of the same cabinet combinations.... Is there anything else I can do? What am I doing wrong? I'm not up for a 16x10 rig but sometimes I think that's what it would take to tame the beast.....
     
  2. saabfender

    saabfender Banned SUSPENDED

    Jan 10, 2018
    Indianapolis
    I don’t know about an answer to your config question. I can only ask this: where are you playing where that kind of on-stage firepower is appropriate?
     
  3. Normally I can get away with lower stage volumes of course but for the few times a year when I pull out the big guns outside with large crowds 1000+ the classic gets cranked up beyond pub / club levels. I would like there to be less speaker protest if possible. The transistor amps seem to be as loud before the speakers have issues with this. Even at lower more normal levels the speakers get frisky with the classic earlier than the other amps at comparable volumes.....power brake? Remove a couple of the 6550s and rebias? ....
     
    Last edited: Jan 9, 2019
  4. saabfender

    saabfender Banned SUSPENDED

    Jan 10, 2018
    Indianapolis
    Personally I am finding few and fewer occasions where a big amp makes any kind of sense. I’ve got a large SS stack that can take the window out of a hatchback. It hasn’t rolled in a year.

    Small combo onstage with the bulk of my sound through the PA. IEMs. This reality has thoroughly cured my GAS for big, awesome amps. There’s a very nice Acoustic 360 locally for a reasonable price. As much as I love those amps, having one makes no sense for me.
     
    Mark Andrew likes this.
  5. I agree that they are becoming less relevant and mine only rolls a couple of times a year. I have acoustic theater gigs coming up and I seven ressurected an old combo. However as a tribute band to the age when a backline was present and things were loud i will still be lugging a backline for a while yet even if it's just to fill the stage and and be obsolete :)
     
    Bugeyed Earl likes this.
  6. saabfender

    saabfender Banned SUSPENDED

    Jan 10, 2018
    Indianapolis
    Who's your band? I'm starting to think this is a direction an aging rock bass player might go.
     
  7. Wasnex

    Wasnex

    Dec 25, 2011
    Is your problem over excursion of the speakers or the output section of the amp getting farty because you are driving it too hard. If I understand, you have an 810 with Faital Pro drivers. Is this a ported design or sealed? Was the cab tuned to the drivers? What is the power rating of the cab and frequency response of the cab?

    If an HPF and reducing bass is not fixing the problem then you need another speaker to share the load, or a different speaker that is up to the abuse.

    I don't recommend pulling tubes as that impacts the impedance matching between the tubes and speakers, which can be dangerous to the amp. If you decide to go this route, pulling half the tubes doubles the expected load at the speaker terminals. Make sure to balance the number of tubes in circuit on each side of the output transformer. An easier/safer solution is simply turn down.
     
    Mark Andrew likes this.
  8. Thanks for the advice any tube pulling would be done by the tech that restored the amp not by me luckily. I usually use a 210 115 setup the 210 has basslites suited to the cab the 15 is a pr400 from faital also recommend and modelled to see if it would.work with the cab. The 15 is damn sturdy the 10s show signs of trouble. I also have a 410 115 Peavey pro series rig with the same faital in the 115 and stock 10s and I make occasional use of an ampeg fridges no idea on the specs whenever available. To be honest the 15 upgrades put both setups in a totally different league and I'm happy with the sound. I'm more curious about how of 3 amps with practically identical RMS ratings that the valve amp gives the speakers such a hammering? My 2001 did the same and at the time I was told that the transient peaks of such large valve amps are enormous and that was the reason for my problem. Maybe that's BS? The 210 is maybe destined for light duty in future or another upgrade...I'm no stranger to the volume knob and turn down happily..... But occasionally like to bring some thunder of course...and hope to understand better what's going on . :)
     
    Last edited: Jan 9, 2019
  9. Wasnex

    Wasnex

    Dec 25, 2011

    It could be the voicing of the amp allows lot's of lows to pass. Or perhaps the damping is low so the amp does not control the speakers very well. To be honest, the amp ratings are pretty meaningless as they only indicate minimum power and different companies use different methods and standards.

    IMHO 200W of low frequency content is a lot of power for a 210. Take a look at the attached cabinet design document for the 10" basslite. Viewing the cone displacement graphs may give you an idea of what the problem is. The HPF needs to limit the amp from feeding the cabinet power much below the port tuning frequency (Fb). I believe it's fairly common the run the HPF about 1/4 octave below Fb, but you may need to run it higher to avoid exceed the drivers excursion limits.

    You can deduce Fb with an online signal generator and a bit of rice. The cone's movement will be minimized at Fb.

    If you have two matching 115 cabs with the 15PR400, I think this would be a better choice.
     

    Attached Files:

  10. All very interesting thanks. The HPF did help matters considerably and I am still experimenting with it. At present I take the larger rig for the outdoor venues and the 210 115 for the rest. We have s long spell of acoustic gigs so experimenting at higher volume will have to wait ;) and I'm back to a combo. I popped another faital in my tiny marshall combo and that will get acoustic duty...
     

    Attached Files:

    Last edited: Jan 9, 2019
    Bugeyed Earl and Wasnex like this.
  11. So the ladies called in sick and I played around with the HPF getting it set to the tuning of the 210...... And presto no farting can get the amp blisteringly loud (I went un ear plugged ouch ) and can start to get the tube breakup I have never been able to reach before speaker meltdown with the classic..... This mo fo is a happy camper....Beast tamed...
     
    Last edited: Jan 15, 2019
    Coolhandjjl likes this.
  12. Coolhandjjl

    Coolhandjjl Supporting Member

    Oct 13, 2010
    Appleton
    I have the FDeck HPF. Last pedal in my chain.

    Best tool ever!
     
  13. Indeed.... My amp tech knocked up a prototype and wants it back to change the case and knobs and for final tweeking....no way...... Not unless I get another ;)....
     
  14. Really helpful thanks lost some rice but dialled in a treat ......
     

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