8ohm versus 4 Ohm

Discussion in 'Amps [BG]' started by pakman, Mar 22, 2014.


  1. pakman

    pakman

    Joined:
    Mar 22, 2014
    Hi, new here so Hi! this forum has always come up when i've been stuck so thought i'd join and hopefully be able to pass on some knowledge, here and there but.... I am stuck again, and need some help please?

    I have an 8ohm Trace Elliot 1028H cab with an Ampeg Micro-VR

    It's a great bit of kit but just shy of loud enough for what i need so i am going to buy the Ampeg PF-350 or PF-500

    my question is, if the PF-500 is 500w at 4ohm, then what is it at 8ohm, and the same with the PF-350?

    Thank you so much in advance

    Paul
  2. scottfeldstein

    scottfeldstein Supporting Member

    Joined:
    Jun 20, 2011
    Location:
    West Bend, Wisconsin
    About half the wattage at 8 ohms. Which is usually fine, because most 8 ohm cabs can't take more than that anyway. Your 2x10 cab doesn't need 500w, for example.

    Your Micro VR is only operating at 100w with that 2x10 cab.
  3. tjh

    tjh Supporting Member

    Joined:
    Mar 22, 2006
    Location:
    Minnesota
    all of this info is readily available on the Ampeg website ...

    ... PF350 is 250 watts @ 8 ohms, 5% THD

    ... PF500 is 300 watts @ 8 ohms, 3%THD
  4. JimmyM

    JimmyM Supporting Member

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    Apopka, FL
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    Endorsing: Ampeg Amps, EMG Pickups
    Slight correction, Scott...Micro VR operates at 150w @ 4 ohms.

    In all honesty, I think the way to go with that cab is the PF800 (400w @ 8 ohms). I have a Micro VR and used to have a PF350 till a soundman toppled my rig over on a hard stage a couple months ago, and the extra headroom is greatly appreciated by me. Makes it hit harder IMHO and hold together better at louder volumes. I don't come anywhere near using all it can give me, but it sure sounds good. They all sound good, but the headroom does seem to make a difference.
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  6. scottfeldstein

    scottfeldstein Supporting Member

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    Thanks, Jimmy. Case closed!
  7. pakman

    pakman

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    Mar 22, 2014
    Nice one Jimmy, and thank you...

    I'm sorry, but which amp are you, actually recommending; the PF800?

    Thanks, Paul
  8. Downunderwonder

    Downunderwonder

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    Back up.

    I can fart my Trace 8ohm 1518 with 250w @ 4ohm amp.

    Grab another cab before chasing loudness with watts. There is only so much your little cab can take.
  9. JimmyM

    JimmyM Supporting Member

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    Sorry if I wasn't clearer. Yes, the PF800. They all sound good, and I just used my Micro VR on a couple gigs last week and it does sound very good, but the PF800 just seems to have a little extra oomph to it, and I believe it's because of the extra headroom.
  10. pakman

    pakman

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    Mar 22, 2014
    I'm only concerned with not blowing s*it up, i just need a bit of extra volume without breaking the bank imo because i am poor presently and if i know the loss from 8 to four i'm sorted
  11. JimmyM

    JimmyM Supporting Member

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    Oh, sorry...for some reason I thought that cab was bigger than it is. I do agree that adding a second identical speaker is the way to get more volume over adding watts. But watts don't hurt when it comes to micros, so if you can keep your itchy trigger finger off the volume knob, I still say the PF800 is the way to go + a second cab. But really, just adding a second cab will make a goodly bit of difference in volume, more so than extra wattage, and there's nothing wrong with the Micro VR.
  12. pakman

    pakman

    Joined:
    Mar 22, 2014

    Oh okay Jimmy,

    and i must admit i love the sound of my VR too so reluctant to get rid..... what second speaker would you recommend another 1028H?
  13. JimmyM

    JimmyM Supporting Member

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    Well since you have it already, I would say yes, get another identical cab. Mixed cabs can work, but it's a real crapshoot, and the only way to know if they'll work is to try it, which costs money. But matching cabs always work.
  14. Downunderwonder

    Downunderwonder

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    Those 1028 cabs are commonly abused and drivers replaced. If yours has original drivers it would be well worth seeking out another. GC usually has a few in stock.
  15. Jim C

    Jim C Supporting Member

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    Nov 29, 2008
    Change of opinion?
    You have many posts that have questioned why anyone would need more than 30 watts on a normal gig, or that a PF350 can play any stage with right cab.
  16. JimmyM

    JimmyM Supporting Member

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    I still believe it. I did two gigs with the Micro VR last week just for fun. It's just that the quality of sound in a micro seems to improve with more headroom. I've played the PF500 and PF800 side by side, and I've played the PF350 and Micro VR side by side too, and in both cases, they sound basically the same but the extra headroom really seems to benefit the whomp factor. So I have to go with what my ears tell me.
  17. Jim C

    Jim C Supporting Member

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    Nov 29, 2008
    That's what we've been trying to tell you for years ;)

    Extra power is often times not used for volume but rather to have increased headroom, improved transient response, and a fuller, tighter, extended low end.
  18. JimmyM

    JimmyM Supporting Member

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    I only notice it to a large degree on micros. Regular SS and tube amps, not nearly as much. So I still stand by what I used to say, except for micros ;)
  19. Downunderwonder

    Downunderwonder

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    There should be a Whomp Factor attached to every wattage spec. I still doubt there's any need for a 400w amp for a little old 2x10 or two.

    Having said that, I don't know how pitiful is the WF of Ampeg micros. It's none too flash on my GK. My Trace is only 50w more but there is no comparison in WF. The 200w GK does much better with 2 cabs.

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