I am currently looking at a fender bassman head for sale in my area. I have not been able to contact the guy yet but I wondered becouse its an amp head what olm speaker cab to use with it. I have 2 2x12 vintage 30 8 olm cabinets and a 8 olm 4x10 jenson speaker cabinet. I have never owned an amp this old. can I use any of my speaker cabs with it or maybe a 2x15 cab with it? Anybody know what speaker olm the cabinet should be to match the head?:33:
fender bassman head question
- Thread starter philthis
- Start date
the guy who invented fire
Fuzzy. Guitars
Re: fender bassman head question
It's spelled ohm not olm and what you're asking about is what impedance the amp runs at.
Bassman heads are 4 ohm loads so you need an 8 ohm cab for it.
It's spelled ohm not olm and what you're asking about is what impedance the amp runs at.
Bassman heads are 4 ohm loads so you need an 8 ohm cab for it.
LReese
Sausage Gravy
Re: fender bassman head question
They're 4 Ohms, so optimally you need a 4 ohm cab but Fenders typically can tolerate a slight mismatch - 2 Ohm (I personally would not try this - its tougher on the amp) or 8 ohm.
Weber also makes an impedance matcher if you want to go for that.
Edit - You can also do 2 8 ohm cabs in parallel to give that 4 ohm load.
They're 4 Ohms, so optimally you need a 4 ohm cab but Fenders typically can tolerate a slight mismatch - 2 Ohm (I personally would not try this - its tougher on the amp) or 8 ohm.
Weber also makes an impedance matcher if you want to go for that.
Edit - You can also do 2 8 ohm cabs in parallel to give that 4 ohm load.
Last edited:
F
Funkfingers
Guest
Re: fender bassman head question
Over the decades, the name Fender Bassman has graced numerous different amplifier designs with wildly differing performance capabilities. Which exact model are you checking out?
Over the decades, the name Fender Bassman has graced numerous different amplifier designs with wildly differing performance capabilities. Which exact model are you checking out?
Lake Placid Blues
New member
Re: fender bassman head question
They are mismatched with 8 ohm cabs all the time. They hardly ever blow up.
They are mismatched with 8 ohm cabs all the time. They hardly ever blow up.
the guy who invented fire
Fuzzy. Guitars
Agileguy_101
Master of his Domain
Re: fender bassman head question
I wouldn't take the chance personally - although my needs may be different from yours, I'm a gigging guitarist that uses my Bassman a lot (10-15 hours a week just for band practice) so I can't afford to have something happen to it.
I wouldn't take the chance personally - although my needs may be different from yours, I'm a gigging guitarist that uses my Bassman a lot (10-15 hours a week just for band practice) so I can't afford to have something happen to it.
Re: fender bassman head question
its a 1970 silver face head. I would like to pick up two bassman heads and run them in stereo for my clean tone. Miked they should easily be loud enough to stay clean at club or practice level. I dont need the headroom of a twin because lets face it, I am not good enough to play stadiums.:33:
its a 1970 silver face head. I would like to pick up two bassman heads and run them in stereo for my clean tone. Miked they should easily be loud enough to stay clean at club or practice level. I dont need the headroom of a twin because lets face it, I am not good enough to play stadiums.:33:
Stratman
Guitaris Maximus
Re: fender bassman head question
There is some misinformation on some of the above post...
The output of the Bassman Head, actually depends on which model / circuit within the Bassman you have...
The standard transformer of for the 6G6A, AA270, AA864, AB165, and AC568 is part number 125A13A (Also part numbered as 022871 and 018343), which has a 4 ohm output
[TABLE="width: 328"]
[TR]
[TD="width: 109"]125A13A[/TD]
[TD="width: 98"]-->[/TD]
[TD="width: 98"]022871[/TD]
[TD="width: 77"]-->[/TD]
[TD="width: 98"]018343[/TD]
[/TR]
[/TABLE]
For example,
59 Bassman LTD has an output impedance of 2 ohms
Bassman with AB165 (Or others listed below with the 125A13A transformer) circuit have an output of 4 ohms
[TABLE="width: 577"]
[TR]
[TD="width: 170"]Bassman circuits
[/TD]
[TD="width: 88"][/TD]
[TD="width: 98"][/TD]
[TD="width: 88"][/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]5F6A[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]45249[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]6G6[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A5A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]6G6A[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]AA270[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]AA864[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]AB165[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]AC568[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 170"]Bassman 70[/TD]
[TD="width: 88"][/TD]
[TD="width: 98"]013897[/TD]
[TD="width: 88"][/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 170"]Bassman 135[/TD]
[TD="width: 88"][/TD]
[TD="width: 98"]013692[/TD]
[TD="width: 88"][/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[/TABLE]
BTW - Using a 8 ohm cabinet (Speaker load) will not hurt your amp, it just will lose some headroom...
Here is a old Bassman with the AB165 circuit (4 ohms)
I used to use it to drive a Fender Vibratone and 2 12 inch Jensen C12 8 ohm speakers wired to 4 ohms, thus ending up with a 5.6 ohm loading. Never had any problems with that setup.
There is some misinformation on some of the above post...
The output of the Bassman Head, actually depends on which model / circuit within the Bassman you have...
The standard transformer of for the 6G6A, AA270, AA864, AB165, and AC568 is part number 125A13A (Also part numbered as 022871 and 018343), which has a 4 ohm output
[TABLE="width: 328"]
[TR]
[TD="width: 109"]125A13A[/TD]
[TD="width: 98"]-->[/TD]
[TD="width: 98"]022871[/TD]
[TD="width: 77"]-->[/TD]
[TD="width: 98"]018343[/TD]
[/TR]
[/TABLE]
For example,
59 Bassman LTD has an output impedance of 2 ohms
Bassman with AB165 (Or others listed below with the 125A13A transformer) circuit have an output of 4 ohms
[TABLE="width: 577"]
[TR]
[TD="width: 170"]Bassman circuits
[/TD]
[TD="width: 88"][/TD]
[TD="width: 98"][/TD]
[TD="width: 88"][/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]5F6A[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]45249[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]6G6[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A5A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]6G6A[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]AA270[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]AA864[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]AB165[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 88"]AC568[/TD]
[TD="width: 98"][/TD]
[TD="width: 88"]125A13A[/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 170"]Bassman 70[/TD]
[TD="width: 88"][/TD]
[TD="width: 98"]013897[/TD]
[TD="width: 88"][/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[TR]
[TD="width: 170"]Bassman 135[/TD]
[TD="width: 88"][/TD]
[TD="width: 98"]013692[/TD]
[TD="width: 88"][/TD]
[TD="width: 94"][/TD]
[TD="width: 87"][/TD]
[/TR]
[/TABLE]
BTW - Using a 8 ohm cabinet (Speaker load) will not hurt your amp, it just will lose some headroom...
Here is a old Bassman with the AB165 circuit (4 ohms)
I used to use it to drive a Fender Vibratone and 2 12 inch Jensen C12 8 ohm speakers wired to 4 ohms, thus ending up with a 5.6 ohm loading. Never had any problems with that setup.
Last edited:
the guy who invented fire
Fuzzy. Guitars
Re: fender bassman head question
The only Bassman I know of that is not 4 ohms is the 4x10 tweed Bassman and since he said head I assumed it was not the 4x10 combo.
Running a 4 ohm amp at 8 ohms will not really cause any issues and will not lower the headroom in any way however personally I do not like the results.
Running a 4 ohm amp at 2 ohms can also be done and in regards to a Fender Bassman head the transformers are strong enough to take the mismatch w/o many if any issues but you are making the amp work harder than it has to in that situation.
The only Bassman I know of that is not 4 ohms is the 4x10 tweed Bassman and since he said head I assumed it was not the 4x10 combo.
Running a 4 ohm amp at 8 ohms will not really cause any issues and will not lower the headroom in any way however personally I do not like the results.
Running a 4 ohm amp at 2 ohms can also be done and in regards to a Fender Bassman head the transformers are strong enough to take the mismatch w/o many if any issues but you are making the amp work harder than it has to in that situation.
Stratman
Guitaris Maximus
Re: fender bassman head question
Actually the headroom is reduced… It a matter of how much is being transmitted to the speaker load.
Do the math! 8 > 4 With the increase in load “ohms", you lose headroom!
Actually the headroom is reduced… It a matter of how much is being transmitted to the speaker load.
Do the math! 8 > 4 With the increase in load “ohms", you lose headroom!
the guy who invented fire
Fuzzy. Guitars
Re: fender bassman head question
Sorry Larry...you are wrong.
The load in ohms has nothing to do with the headroom.
Sorry Larry...you are wrong.
The load in ohms has nothing to do with the headroom.
Re: fender bassman head question
My experience with the Bassman head is:
8 Ohms will still be in the linear range of the amp
The Fender OT, and Modern quality replacements are plenty stout to handle the over voltage that 8 Ohms causes.
It is always "better" to run it at the intended impedance, but as others have said, players have been running that head at 8 Ohms for a long time.
In the long run, it should not be too hard to sell (or trade) your 16 Ohm speakers and buy a pair of 8 Ohm for your Bassman.
good luck
My experience with the Bassman head is:
8 Ohms will still be in the linear range of the amp
The Fender OT, and Modern quality replacements are plenty stout to handle the over voltage that 8 Ohms causes.
It is always "better" to run it at the intended impedance, but as others have said, players have been running that head at 8 Ohms for a long time.
In the long run, it should not be too hard to sell (or trade) your 16 Ohm speakers and buy a pair of 8 Ohm for your Bassman.
good luck
Stratman
Guitaris Maximus
Re: fender bassman head question
You think so?
You don’t even own these amps…. How can you justify your response.
If you actually own a Bassman, then you would know that playing through a 4 ohm speaker sounds cleaner than playing through the same type of speaker inside the same cabinet but when that other speaker has the 8 ohm rating. The amp needs to have a little increase in volume to have the same volume and that decreases available headroom...
http://www.premierguitar.com/Magazi...ing_A_Blackface_Bassman_In_From_The_Cold.aspx
Notice that in this article, it clearly states change for a 4 ohm to 16 ohm reduces clean sound.. e.g.,
But then again, you keep posting about equipment you don’t actually own, so much for the invention of fire!
You think so?
You don’t even own these amps…. How can you justify your response.
If you actually own a Bassman, then you would know that playing through a 4 ohm speaker sounds cleaner than playing through the same type of speaker inside the same cabinet but when that other speaker has the 8 ohm rating. The amp needs to have a little increase in volume to have the same volume and that decreases available headroom...
http://www.premierguitar.com/Magazi...ing_A_Blackface_Bassman_In_From_The_Cold.aspx
Notice that in this article, it clearly states change for a 4 ohm to 16 ohm reduces clean sound.. e.g.,
Many guitarists play their 4Ω Bassman heads into a 16Ω 4x12 cabinet, thereby reducing the available clean output power.
But then again, you keep posting about equipment you don’t actually own, so much for the invention of fire!
Last edited:
F
Funkfingers
Guest
Re: fender bassman head question
pcorn:
pcorn:
guitfiddle
firstlessonologist
Re: fender bassman head question
There's really no problem here, OP. You have three 8 ohm cabs, and the outputs on the Bassman are wired in parallel, so you just hook up two of your 8ohm cabs and the head sees 4 ohms. No problem. Even if you only hook up one cab, there will be no problem running that amp into an 8 ohm load day in and day out.
There's really no problem here, OP. You have three 8 ohm cabs, and the outputs on the Bassman are wired in parallel, so you just hook up two of your 8ohm cabs and the head sees 4 ohms. No problem. Even if you only hook up one cab, there will be no problem running that amp into an 8 ohm load day in and day out.
Last edited:
Re: fender bassman head question
thnx to everyone who contributed to this question. I wasnt sure what the head ohm would be or if my cabs would work with it. all the newer stuff I buy has said basically its meant to work with an 8ohm cab and all I ever did was just plug in my cab and play. my 4x10 cab is 8ohm and my 2 2x12 cabs are both 8ohm so its been really easy to use them. sounds like I can use them still but if I want more head room I can run them in parallel and to get more clean head room. if I want the bassman head to break up earlier I can run one of my cabs into it and it will break up sooner according to the article that Stratman posted which I found really usefull as well. I dont like hauling combo amps or 4x12 cabs around because they are bulky and heavy as most of us know by hard experience. I was hoping to use my different speaker cabs idea to get as much tone versatility out of the head as possible-the 4x10 jenson cab for jingly sparkly tone and the 2 2x12 vin 30 cabs for more midrange. Anybody have a suggestion or experience with a good 15 inch speaker for this type of amp head?
thnx to everyone who contributed to this question. I wasnt sure what the head ohm would be or if my cabs would work with it. all the newer stuff I buy has said basically its meant to work with an 8ohm cab and all I ever did was just plug in my cab and play. my 4x10 cab is 8ohm and my 2 2x12 cabs are both 8ohm so its been really easy to use them. sounds like I can use them still but if I want more head room I can run them in parallel and to get more clean head room. if I want the bassman head to break up earlier I can run one of my cabs into it and it will break up sooner according to the article that Stratman posted which I found really usefull as well. I dont like hauling combo amps or 4x12 cabs around because they are bulky and heavy as most of us know by hard experience. I was hoping to use my different speaker cabs idea to get as much tone versatility out of the head as possible-the 4x10 jenson cab for jingly sparkly tone and the 2 2x12 vin 30 cabs for more midrange. Anybody have a suggestion or experience with a good 15 inch speaker for this type of amp head?
trevorus
Modsterbator
Re: fender bassman head question
Tube amps are forgiving to loads a little bit, often to the lower ohm load. Some amps, for protection from a cord being pulled from an amp while playing, will have a shorting jack. Having a near zero ohm load is less bad for a tube amp than a too high load. Open circuit is really bad for a tube amp. That can cause flyback voltages which can destroy things. Don't worry that much about little bit of mismatch with a tube amp (in most circumstances). In your case, it's easy to run two 8 ohm loads in parallel to get 4 ohms. With a Bassman and 2 cabinets, you should be loud enough for anywhere.
Tube amps are forgiving to loads a little bit, often to the lower ohm load. Some amps, for protection from a cord being pulled from an amp while playing, will have a shorting jack. Having a near zero ohm load is less bad for a tube amp than a too high load. Open circuit is really bad for a tube amp. That can cause flyback voltages which can destroy things. Don't worry that much about little bit of mismatch with a tube amp (in most circumstances). In your case, it's easy to run two 8 ohm loads in parallel to get 4 ohms. With a Bassman and 2 cabinets, you should be loud enough for anywhere.
