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Non ADA Gear => Speakers & Cabinets => Topic started by: McLeanAB on November 19, 2016, 04:02:30 AM

Title: Watts and Ohms and Cabs and Oh My!
Post by: McLeanAB on November 19, 2016, 04:02:30 AM
Hey ADA junkies...

 I have a Marshall 1960av and an ISP Technologies Stealth Power Amp and an ISP Theta rack preamp. I've upgraded the old V30's (didn't like 'em) to two 8ohm Greenbacks 25 watts on top and two 16ohm Creamback 65watts on the bottom... it sounds amazing and the Stealth can handle ohms down to 1ohm or so, so there's no danger there...

What I AM curious about is the 'spread' of watts from the power amp (90 watts per side, but currently running mono so 90 watts) 'across' the speakers. Do the Greenbacks 'absorb' a full 25 watts each and the Creambacks a full 65 watts? How does the distribution of watts from the poweramp spread across speakers? Any and all information is greatly appreciated... I'd love to run this cab stereo, but I'm afraid that 90 watts in each (running stereo) side as opposed to 90 in the whole cab (running mono) might blow the Greenies... let me know what you know so my speakers stay happy!
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on November 19, 2016, 07:19:10 AM
I just looked it up and you need at least 4 ohm on the output, I think if you go down to 1 ohm you will blow it up. So 4 ohms is the minimum !!

Now for the cab, how did you wire it? If I remember correctly those AV cabs have dual inputs and a mono stereo switch.
It's not such a good idea to mix different speaker impedances in one cab. In your case (depending how they are wired) the greenbacks will "absorb" twice the power of the creambacks because the GB's are 8 ohms and the CB's are 16 ohms.

So let me know the hookup and I can tell you what's safe and what's not. You can always rewire them to get in a safe mode.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: vansinn on November 19, 2016, 02:04:34 PM
For mono operation, wire the two 8 Ohm Greenbacks in series for 16 Ohms across those, then this 16 Ohm series circuit in parallel with both 16 Ohm speakers. You'll end up with a 5.3 Ohm load on your amp.

This will result in fairly even load on each speaker; the two 8 Ohm 25 watters would now take 50 watts across, so the other two should be presented with the same, meaning you cannot load the 65 watters to their max, but only to what the two 25'ers can take combined.

Lousy ascii art schematic :)

   +-8--8-+
--+--16--+--
   +--16--+
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on November 19, 2016, 02:47:11 PM
In case of Van's schematic each CB will have 30W and the 2 GB combined will have 30W, in case of an output of 90W.So this is safe for the all speakers.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: McLeanAB on November 19, 2016, 03:26:24 PM
In case of Van's schematic each CB will have 30W and the 2 GB combined will have 30W, in case of an output of 90W.So this is safe for the all speakers.

Ugh!  So, as of now, with the two Greenies on top, two Creams on bottom, running with the 'traditional' wiring of the 1960av cab (I didn't alter it at all) so the stereo to mono (8ohms stereo with option of 16ohm or 4ohm mono - this is the labeled cab jacks not the speakers) I should run the the 16ohm mono jack (which equals, what... 12 ohms?) and just keep things mono?  Will THAT keep the speakers safe for the moment?

I would totally rewire according to VS diagram, but I've no idea how to do that!!!!  :)

Hmmmm... anyone want to trade a pair of 8ohm Greenbacks for a pair of 16ohm Greenbacks and I can just be done with this??  :)

Thanks for the info fellas!
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: rnolan on November 20, 2016, 03:46:36 AM
So if the GBs are 8 ohm and CBs are 16 ohm, you can wire one GB and one CB per side in parallel (+ve to +ve, -ve to -ve) which will give you ~ 11 ohms per side. The amp will output less into the higher load (90 w into 4 ohms, maybe 55 w into 11 ohms ?) and run in stereo like that. And mono for the cab will be 5.3 ohms so ok for the poweramp for one channel (80ish watts into 5.3 ohms ?).  However some cab stereo/mono cab switching set ups also include some other circuitry in the switch for impedance matching.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: vansinn on November 20, 2016, 10:02:47 AM
Yep to all above wiring considerations.
As Nolan stated, dunno if there might be additional components to consider.
You could make us a pic from the inside of the jack/switching/wiring area..
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on November 20, 2016, 03:47:58 PM
Ok in your case MC ,this would mean;

Mono 16 ohm input: 10.6 ohms
Mono 4 ohm input: 2.66 ohms ==> DON'T USE THIS !!! your amp won't like that.
Stereo each input:5.33 ohms

Now this how a Marshall cab is usually wired.So to make sure plug in a cable and use and ohm meter to measure the resistance of each possibility.The dc resistance will always a bit lower.
If you can post your measurements here so we can check them.

Because of the mismatch in impedances the GB will take 2/3 of the power and the CB 1/3 of the power.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: McLeanAB on November 20, 2016, 04:21:33 PM
Hey there MJMP!

Here's what I'm doing... I'm going from only one channel output on my Stealth power amp (I'm assuming 4ohms) to the 16ohm input on the back of the Marshall input jack.  MONO.

So everything is safe for the moment, yes?

Here's what I think I'm gonna do... trade out the 8ohm Greenies for two 16ohm Greenies... OR, just go up and get the 75 watt Creambacks G12H's at 16ohms each and use the cab in stereo.

Thanks again for all the info!
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: McLeanAB on November 21, 2016, 07:36:12 AM
Okay, gentlemen...

It seems I might land some 16ohm 25 watt Greenbacks to compliment my 16ohm Creambacks in my Marshall 1960 cab...

Since the ohms will all match, running mono from my Stealth at 90 watts and seemingly 4 ohms, can I run stereo from the Stealth at 90 watts per side and not blow the Greenies?  When the cab is in stereo, it's 8ohms per side (even though the Stealth is 4ohms which is okay).

So back to my first question:  how are watts 'distributed' across the speakers?  If it's 90 watts per side, with a 90 watt total between the GB and CB, will it be safe and distribute only 25 to the GB and the other 65 to the CB?

Let me know, as I'd love to have a stereo cab!
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on November 21, 2016, 09:58:06 AM
According to do specs the amps puts out 45w/side at 8 ohms,so if all speakers are 16 ohms each one will use half the power, so the GB will get 22.5w and the CB also. Should be safe for both but it's close for the GB.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: GuitarBuilder on November 21, 2016, 12:23:17 PM
Check out the attached article - it has every conceivable 4x12 wiring combination.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Harley Hexxe on November 21, 2016, 02:46:06 PM
According to do specs the amps puts out 45w/side at 8 ohms,so if all speakers are 16 ohms each one will use half the power, so the GB will get 22.5w and the CB also. Should be safe for both but it's close for the GB.

  That could be an interesting sounding stereo cab. With one speaker almost driving to full power and one coming through cleaner, that could be an interesting tone.

    Harley 8)
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: McLeanAB on November 22, 2016, 06:15:40 AM
According to do specs the amps puts out 45w/side at 8 ohms,so if all speakers are 16 ohms each one will use half the power, so the GB will get 22.5w and the CB also. Should be safe for both but it's close for the GB.

So, I'm guessing stereo (90 watts per side 8ohms each side) will still overload the Greenies?
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: rnolan on November 22, 2016, 06:41:02 AM
Possibly, e.g. 2 x 25 what 16ohm speakers in parallel will be 50 w 8 ohm.  If the amp delvers 90 w into 4 ohms it will deliver less (usually) into 8 ohms ~60 w.  Unless you play full on thrash that should ok as the output wont be full the whole time.  Overpowering speakers is a valid concept for headroom but you have to be careful or you will blow cones.  Much safer to match the maximums...
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on November 22, 2016, 06:48:22 AM
It doesn't put out 90W at 8 ohms, only 45W according to the amp specs.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: rnolan on November 22, 2016, 06:52:58 AM
Then all is good then, 5 w of speaker handling to spare  :headbanger: .
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: McLeanAB on November 22, 2016, 09:15:03 AM
Found a local pair of 16ohms RIGHT after I sold an old lovely classical guitar...  just threw in the 16ohm Greenies with the 16ohm Creamies...  the volume is now much more balanced and sounds amazing!!!!

Thanks guys!
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: rnolan on November 22, 2016, 10:58:33 AM
 :whoohoo!: Fantastic  :thumb-up:
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: vansinn on November 23, 2016, 02:01:07 AM
I have no such fancy things, and go Green with envy seeing the Back of such Ohm-struck noise boxens..
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on November 23, 2016, 03:48:30 AM
I have no such fancy things, and go Green with envy seeing the Back of such Ohm-struck noise boxens..

 ;D
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on November 23, 2016, 03:49:55 AM
BTW MC, is there a big difference between both the GB and the CB?
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: McLeanAB on November 23, 2016, 06:41:02 AM
BTW MC, is there a big difference between both the GB and the CB?

Yes... they are sonically in the same ball park, along with the 75 watt G12H Creamback... both Creambacks are meant to be, if I understand correctly, a higher wattage version of the G12M 25 watt Greenback. 

However, the 75 watt has a bit more high end than the Greenie which has that lovely mid range bark... the 65 watt Creamback is much more subdued and warm sounding... which makes it a beautiful blend with the Greenie...  with that being said, some folks think the 65 watt sounds great isolated, but gets buried in a mix, whereas the Greenie will almost always shine through...

https://www.youtube.com/watch?v=_IOHz6g5lfw

https://www.youtube.com/watch?v=lpnTSxGHmGo

https://www.youtube.com/watch?v=12lXMmU73Bo

If it's any help, I think it would be amazing to have a 4x12 of Greenies and a 4x12 of 65 watt Creambacks in stereo!!!! 
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on November 23, 2016, 07:38:54 AM
Well it's strange, I have an old '68 marshall cab with greenbacks in it and it sounds more like creambacks then like the greenbacks. I already noticed that the new greenbacks don't l sound like the old greenbacks when I A/B a modern marshallcab with GB's and mine. Could maybe be the speaker cloth which is a basketweave.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Harley Hexxe on November 23, 2016, 03:03:35 PM
Hey MJMP,

    Which ones are in your 68 cab, the 25 or 30 watt?

    Some of the discussions I've been reading about have had a lot of info on the 25 vs the 30 watt green backs. Most seem to agree that the 25 watt sound darker than the 30 watt, and which is better for what style of music etc...

    It seems the popular choice of vintage reissues for today's guitar players is the 30 watt with the boutique amps that are out now. Not that I would put those in any of my split stack cabs. If I did swap out my speakers, I'd probably go with vintage JBLs or Altecs if I could find them at a reasonable price. I'm good with the 50 watt speakers that are in there now.

     Harley 8)
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on November 24, 2016, 09:40:20 AM
I have the M series, so the 25W, the 30W is the H serie. Those sound also very good. A friend of mine has also an old cab but with the 30W in them.  Sounds a bit more heavy and more top end while the 25W sounds warmer. That's why I combine them with a V30 cab.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Dante on December 04, 2016, 03:15:18 PM
Okay guys, riddle me this..... when I rewired my H&K cab for stereo, I did not write down how it was originally connected  :facepalm:

It was: Four 8 ohm speakers wired for 8 ohms Mono, with an in/out jack to run into another speaker cab

I did not discard any wires, and here's what i have:
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Dante on December 04, 2016, 03:49:43 PM
And here's how I hooked it up, but I'm worried is not correct:
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Harley Hexxe on December 04, 2016, 05:08:51 PM
Hey Dante,

    If you only want to run this cab in stereo, then remove the two wires that bridge the I/O jacks. This will give you the stereo setup @16 Ohms per side by plugging into each jack. The "Out" jack will become an "In" jack. Those two wires parallel the speaker connections to bring the cab back down to 8 Ohms.

     Harley 8)
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on December 04, 2016, 06:23:35 PM
Hey Dante, no need worry ,it's good like it's wired now.  :thumb-up:
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Harley Hexxe on December 04, 2016, 06:47:03 PM
I guess I misunderstood the question.

Personally, I would have wired up the stereo pairs in parallel to get more punch out of the speakers @4 Ohms per side. Series wiring always seemed to thin to my ears.

   Harley 8)
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Dante on December 04, 2016, 09:08:22 PM
Thanks Harley, that's what I did to make it a stereo cab...I cut those connections. I soldered them back up and the wires just didn't seem right. Later, I'll put a switch in between those jumpers to make it a stereo/mono cab.

Thanks MJMP, it just seemed weird to me, and I didn't wanna blow shit up ;)
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: rnolan on December 05, 2016, 12:31:44 AM
Hey Dante. Originally it could have been wired either each pair in parallel, then the 2 pairs in series (8 + 8 = 4, then 4 series with 4 = 8) or more likely (as I assume you changed as little of the wiring as you could) the 2 pairs each in series (as per your pic) then the 2 pairs in parallel (8 series 8 = 16, 16 + 16 = 8) , also most quad boxes seem to be wired this way.

If you go with this configuration, you can use one normal jack and one switching jack (like I posted re how I have one of my cabs), or use a switch  :dunno: .

Depending on the amp(s) you want to use (and particularly if they have SS output stages eg MT100/200) a better wiring IMO (and as Harley suggested) is to parallel each pair (8 + 8 = 4) to get the most from the amp in stereo.  Then series the 2 pairs (4 series 4 = 8) .  So cab then is 8 ohms mono, 4 ohms per side stereo (which is what was asked for in a previous post).  You could do it with a switch or 3 switching jacks. Noting that the SL (switch lugs) connect to the tip (+ve) when no jack inserted

(http://adadepot.com/data:image/png;base64,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Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: vansinn on December 05, 2016, 01:42:04 AM
Just to note As already said, yes, you could withe each speaker set in parallel for a resulting 4 Ohm load - but do pay attention to which output impedance you amp is capable of.
If you amp is solid state, not problem. If it's a tube amp, do make sure to set the impedance selector to 4 Ohm, and if it's fixed 8 Ohm, do not wire the speaker in parallel.

With tube amps, you can always use speaker wirings at higher Ohms than the amp, but never lower, as this could fry the output transformer.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: rnolan on December 05, 2016, 02:05:46 AM
And to add to what Van is saying (careful), if you use switching jacks the way I've done, you have make sure you only plug into the correct jack or jacks for either mono or stereo operation.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Dante on December 05, 2016, 07:26:40 AM
You're all correct!

I had it wired for stereo (8 + 8 = 16 ohms per side) and found myself cranking my MT200 around 3/4...when I usually have it around 1/2 volume. I thought I'd switch it back to 8 ohms mono and simply use a second cab. We'll see how it sounds when I crank it up at practice ;)

Thanks for the help fellas
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: vansinn on December 05, 2016, 09:43:54 AM
But wait! the MT200 has solid state outputs, and does 100 Watts @ 4 Ohm per channel, so you can safely wire your two 8 Ohm speakers [per side] in parallel, for a 4 Ohm load on the amp [per channel].

I don't remember which speakers are in your cab, so dunno how much power they can handle before frying, so go check that out, but else you'll be save - I mean, your speakers.. unless you sit on them as the blow :lol:
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Dante on December 05, 2016, 12:01:21 PM
60w each

100w would be fine....I may rewire it for 4 ohms later
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Harley Hexxe on December 05, 2016, 04:14:35 PM
I would be curious to hear your review of the sound difference when you re-wire the speaker pairs in parallel and try it that way. Not just the amount of power you have to drive it with, but the difference in the speaker response to your guitar.

    Harley 8)
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Dante on December 05, 2016, 09:52:02 PM
Quote
I would be curious to hear your review of the sound difference when you re-wire the speaker pairs in parallel and try it that way. Not just the amount of power you have to drive it with, but the difference in the speaker response to your guitar.
Me too  :thumb-up:

Just for posterity; I'd basically be doing this on each side of the 4x12:
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Harley Hexxe on December 06, 2016, 05:16:34 AM
Yes, exactly :thumb-up:
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: MarshallJMP on December 06, 2016, 05:40:40 AM
Yep correct!
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Kim on December 06, 2016, 07:04:40 AM
I concur.   ;)
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: vansinn on December 06, 2016, 08:48:53 AM
I shall :bow: upon hearing the results..
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Dante on December 06, 2016, 02:52:05 PM
Okay...while I have not tried the 4 ohms per side wiring yet, I finally tested the stock setup (8 ohms mono). I also hooked my 1x12 Thiele cab up to channel B, so I could compare. Honestly, and happily, there isn't a lot of difference between the cabs' sounds...they're both pretty transparent I guess. Of course, I'm in a bedroom, only about half as loud as a gig. I'll bring both cabs to practice next Friday night. They sure sound awesome - of course, they're on opposite sides of the room, so it sounds really big  :banana-rock:

Running the 4x12 cab mono, without the other speaker, it sounds clearer and cleaner to my ears than running stereo. I have never been a fan of running a single box in stereo. I put a wall in my old Carvin cab for this reason (& made it heavier  :facepalm: ) My feeling is the sides should be in separate cabs. I'll hook up a switch later to split / join the 4x12, but I'm good for now

Until I get it all done, I'll just bring two cabs when the sound system allows, otherwise I'm running mono anyway
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Harley Hexxe on December 06, 2016, 03:59:25 PM
Dante,

    I agree with you completely on running a single box in stereo. The stereo ambient speaker frequencies will cancel each other out if they are in phase with each other and make it harder for guitar to cut through in the mix. That was something I first learned about when I got my G-K 250ML.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: rnolan on December 06, 2016, 11:57:23 PM
When I split my old yamaha quad box I put a bit of cardboard down the middle which helped a bit and sounded great with my old MP1 setup (desk, Quadverb, B200s).  The split stack I have split into stereo/mono gets a bit flangy with the MP2 rig but sounds fine when Mike uses it at rehearsals with his MP1 rig.  Separate cabs are definitely the go  :thumb-up: (with at least a gap between them as wide as the widest cab to break the infinite baffle), but more to lug  :facepalm: .
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: Harley Hexxe on December 07, 2016, 06:11:11 AM
Richard,

    At 45 lbs per split stack cab, that's a lot less fuss than a 4x12 cab any way you slice it. :))
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: vansinn on December 07, 2016, 08:53:02 AM
Dante,

    I agree with you completely on running a single box in stereo. The stereo ambient speaker frequencies will cancel each other out if they are in phase with each other and make it harder for guitar to cut through in the mix. That was something I first learned about when I got my G-K 250ML.

I don't have a split stack setup (using emulation into studio monitors), but once had a Roland Jazz Chorus, so at least some experiences.
The Roland chorus was build to have no phasing-out problems, and produced a lovely ambient yet still localized effect.

I can see this phasing issue with a split-stack with i.e. the MP-2, which isn't really true stereo, but rather a mono chorus going to one side, and the other side simply tapping the mono chorus through a 180 deg phase reverse.
While this does generate the lovely effect we all know, even with spaced-apart speakers, the out-phasing gets horrible when physically moving across the sound scape.

My Digitech TSR-24S generates proper true stereo effects, including chorus, flange and multipole chorus.
I'm getting tired of the studio monitor setup, starting to desire a split-stack setup.
If so, I'll simply convert my MP-2 chorus to TrueMono ;) purely to thicken the plot, so to speak, and use the TSR mono-in stereo-return in the MP-2 loop for generating true stereo effects.
Title: Re: Watts and Ohms and Cabs and Oh My!
Post by: rnolan on December 08, 2016, 03:13:47 AM
Thicken the plot with the chorus is how I used to run my MP1.  Depth on 100 and rate 0.0