# 8ohm-4ohm



## Dustman (Apr 1, 2011)

My Traynor YCR-1 is 8ohm, but would it be bad to run a 4ohm cab with it? I've heard they're pretty tough ol' amps, but I don't want to hurt it.


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## CSBen (Mar 1, 2011)

Dustman said:


> My Traynor YCR-1 is 8ohm, but would it be bad to run a 4ohm cab with it? I've heard they're pretty tough ol' amps, but I don't want to hurt it.


Most definately not. Running say a 8ohm cab from a 4ohm output on your amp = ok. Same say for a 16ohm cab from a 8ohm output on your amp = ok. Essentially, the combined Ohm of your cab cannot be lower then the Ohm Output jack. 

If your amp would of had a half power switch, it would have reduced the usage of the output transformer windings (coil) by half, effectively taking it from an 8ohm amp (output) to 4ohm, but alas, that isn't the case for your Traynor.

Cheers,
Ben


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## Dustman (Apr 1, 2011)

Thanks Ben, for the quick response. So if I rewire the 2x12 cabinet from 4ohm to 16 ohm I'll be ok, if I understand what you're saying???


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## CSBen (Mar 1, 2011)

Dustman said:


> Thanks Ben, for the quick response. So if I rewire the 2x12 cabinet from 4ohm to 16 ohm I'll be ok, if I understand what you're saying???


You're most welcome.

As for re-wiring the cab - I can't see how you'd be able to wire the speakers from their current 4ohm to 16ohm?


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## parkhead (Aug 14, 2009)

Don't believe everything you read on the internet



P


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## Dustman (Apr 1, 2011)

CSBen said:


> You're most welcome.
> 
> As for re-wiring the cab - I can't see how you'd be able to wire the speakers from their current 4ohm to 16ohm?


If there are two 8ohm speakers wouldn't wiring in series or parallel determine the ohm rating for the entire cab at either 4 or 16ohm?


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## washburned (Oct 13, 2006)

Yes, but I dislike series wiring with two speakers because a blown coil leaves an open load on the amp output....even worse than half load. There is a lot of controversy about the load on a lot of the old amps: a lot of folks say one step either way won't do any serious damage. We used to run old Twins with dual showman extansion cabs all the time.


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## bcmatt (Aug 25, 2007)

Dustman said:


> If there are two 8ohm speakers wouldn't wiring in series or parallel determine the ohm rating for the entire cab at either 4 or 16ohm?


Yes, you are right Dustman. You could rewire your cab to be in series and be 16 ohms. Your 8 ohm specified amp should be able to handle either a 4 ohm load or a 16 ohm load equally. Tube amps are generally capable of handling a 100% impedance mismatch in either direction. Vintage Traynors are generally overbuilt and shouldn't have a problem. 

If you are concerned, put your hand on your output transformer and see if it is getting really hot. I've heard (not sure where) that if you can't hold your hand on the OT for a full 5 seconds, you are pushing it too hard. Don't know exactly how credible that is, but it seems to make sense to me.

Anyways, the point I just remembered that I was going to make: 
While wiring your cab for 4 ohms or 16 ohms should both be safe (to an equal degree) for most tube amps, it is changing significantly the ratio that your OT is providing and could give very different tones. You may like one much more than the other. The ideal impedance will be the 8 ohms; giving you the tone and headroom the amp designer was going for; but your personal preference may be something else.


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## WCGill (Mar 27, 2009)

parkhead said:


> Don't believe everything you read on the internet
> 
> 
> 
> P


Too funny!


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## CSBen (Mar 1, 2011)

parkhead said:


> Don't believe everything you read on the internet
> 
> 
> 
> P


No kidding..

But as an amp builder - I figure you are Bill Gill from Electroglideamps correct, or just a user - perhaps you could provide your professional's builder insights into the post and enlight the rest of us comon folks..

Cheers!
Ben


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## CSBen (Mar 1, 2011)

Dustman said:


> If there are two 8ohm speakers wouldn't wiring in series or parallel determine the ohm rating for the entire cab at either 4 or 16ohm?


IF being the key word. I had/still don't have an idea what ohm speaker rating your speakers are : ). It sure would determine if you'll be able to wire them in series 8+8 or 4+4..

Cheers
Ben


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## parkhead (Aug 14, 2009)

those old traynors were built without impedance selectors 

the later ones have a 150 ohm 10 watt resistor wired across the output jack to save the OT if the speaker is not plugged in 

they were sold with various speaker cabinets including 16 ohm 2-15's 5.3 ohm 6-10's and so on 
people often used two cabs with one head and you would see the same head matched to the 5.3 ohm load 
4 ohm cab or the 16 ohm cab 

personally I select the impedance to run any amp based on sound 

been doing it for years and have yet to cook an OT 

in the old days they just piled stuff up on stage and plugged it all in 

a modern amp with a chinese output transformer may be questionable ( but the OT probably is not built to the old specs) 

a marshall without a speaker will blow its OT (but I ran my 73 50 watter for 3 years with a pair of Kt66's and the wrong impedance selected ) 

I've built amps and purposely hard wired a mismatched OT to get certain sounds... at that point I retired my marshall still inperfect working order 

a quality vintage amp in good condition with proper value fuses is highly tolerant of mismatches 

the 65 66 bluesbreakers were hard wired for a 16 ohm impedance but shipped with 2-12's wired at 8 ohms ... additionally 
clapton often used a 2-12 extension live for a 200% mismatch (remember no selector) 

ever wonder why that sound is hard to duplicate ... bet you are not running your amp mismatched on 10 

Freaking about impedence mismatches on amp chat pages is highly fashionable... but all anecdotal 

there is substantial evidence that people often used the extension speaker jacks on old amps without negative consequnces 


Bottom line if the primary winding of the OT cannot take the amp's full current it will probably blow at some point even at the correct 

setting ... (see vinatge tweed deluxes as a good example) 



finally just because I typed it on the internet does not mean its true either

p


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## parkhead (Aug 14, 2009)

the primary impedance on a Traynor amp with 2 el34's is 3.8k 

Marshall used 3.4k with 2 el34's 


the primary impedance on a marshall 18 watt amp is 8k 

the primary impedance on a traynor Guitar or bassmate is 5k with el84's


The 18 watters provide the best example ... of designers choosing totally different impedances for a similar appliction


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