fender bassman funny noise

[chris o'donnell]

Hi.

It's been a long tim esince I last posted. Two kids later i'm just starting to get a bit of free time.

I have a Telecaster with a Pile driver set ( great sounding guitar). When I play through my bassman the low e note when played open or close to the nut causes the spears to make a vey heavily distorted vibrating sound. I've chaged two of the speakers and it still happens.

Ha sthis happened to anyone else or does anyone know what the problem might be.

Cheers

Chris.

 

[Jonny]

Could this be fret buzz?

[jpfamps]

What model of Bassman is it (very useful information in diagnosis)? I assume that when you say you changed two of the speakers it is a 4 x 10 RI Tweed Bassman combo. Is this correct?

If it is a 4 x 10 RI Bassman, the speakers in it are undoped and use quite a light cone, so the surrounds are prone to fraying, or indeed tearing. I've had a few RI Bassmans in with this problem, which easy to spot by inspecting the cone edges.

The effect you are experiencing may well also be due to a phenomenon called "blocking distortion" which Fender amps are prone to when too much bass is hitting the power valves. Try reducing the amount of bass (by turning the bass control down!) and see if this improves the matters.

Else their may well be something else wrong with your amp  (eg filter caps) and a trip to a tech may be in order.

[darcym]

I have this problem on a Fender Blues Deluxe on certain guitars.

It's a speaker rattle for sure.

[HTH AMPS]

do you have access to a seperate speaker cab? - running the Bassman into a seperate cab would tell you for sure whether its one of the speakers in your cab or a problem with the amp itself.

[chris o'donnell]

Thanks for the comments guys.

The amp is a Bassman 4 x 10 reissue. I changed two of the lower speakers. I can't seem to reach the top ones as there is little room to work in there. The top two are the original Jensens and the bottom two are now weber blue pups (alnico). I have ruled out fret buzz and I will try the other checks you have mentioned, in the rehearsal studio.

I did turn the bass down but it had little effect.

Can the amp be upgraded by a tech I.E new transformer, choke filters etc, or would  I be wasting good money for little improvement in sound (tone).

I use a telecaster with pile drivers and my les pauls get a go now and then. they have mule / stormy mondayin one and an abraxas / riff raff in the other. the bridge pickk up in the tele is quite a high output pickup. Would this have an effect on the bass problem?


Cheers


Chris.

[jpfamps]

The amp is a Bassman 4 x 10 reissue. I changed two of the lower speakers. I can't seem to reach the top ones as there is little room to work in there. The top two are the original Jensens and the bottom two are now Weber blue pups (alnico). I have ruled out fret buzz and I will try the other checks you have mentioned, in the rehearsal studio.

You will need to remove the chassis to get to the upper speakers. If the amp has Jensens in (is it the hand-wired Ltd Edition version? How old is the amp?) then I would not suspect the speakers, although I don't especially like the Jensen RIs. If it is the version with Eminence speakers in, the these do tend to tear and I would be tempted to have a look at them. By the way if you are going to remove the chassis have someone help you will this, and don't forget the P-clip on the mains cord!

If the speakers have been changed I would double check their phasing as well.

I did turn the bass down but it had little effect.

Probably not blocking distortion then.

Can the amp be upgraded by a tech I.E new transformer, choke filters etc, or would  I be wasting good money for little improvement in sound (tone).

Changing the choke is pointless. Changing the PT is only worthwhile if the plate voltages are way of vintage spec. Changing the OT may be beneficial, although Fender do use good transformers wound on paper like the originals, so a genuine "upgrade" (if such an item really exists) will be expensive, and in my opinion not worth the money, even more so if you are paying someone to do it for you.

I use a telecaster with pile drivers and my les pauls get a go now and then. they have mule / stormy mondayin one and an abraxas / riff raff in the other. the bridge pickk up in the tele is quite a high output pickup. Would this have an effect on the bass problem?

You do need to be careful when using humbucker loaded guitars with Fender amps due to blocking distortion, although from what you say this doesn't seem to be the problem with your amp.

I suspect you have a problem in the power section, possibly the filter caps, although the problem could simply be you need some new correctly biased output valves.

[darcym]

I'll be interested in trying some of this on m Blues Deluxe.

It's the USA early 90's version not the mex version.

I'm using it with a Strat mostly with very low gain pickups (think big dippers) and get the same Buzz. Mine has the Fender speaker in it (not sure what it is rebadged).

I've changed one of the valves on mine to give me more clean headroom and I still get the buzz.

I've just picked up a blues Deville USA 1980's amp  4x10 so I'm going to try the same amp settings and see if I get anything similar.

[chris o'donnell]

Thanks again.

Its a Ltd version and is four years old. Jensen R1s were the original speakers.

Can I safely remove the Chassis to get at the top speakers and not be at risk from the charge that may be held in the amp.

I would like to get the amp back to working properly again. Perhaps I should just get it looked at by a good technician.

When you say phasing of the two speakers, what exactly does that mean.

Would mixing ceramic and alnico speakers have a dramatic effect.


Cheers


Chris

[jpfamps]

I'll be interested in trying some of this on m Blues Deluxe.

It's the USA early 90's version not the mex version.

I'm using it with a Strat mostly with very low gain pickups (think big dippers) and get the same Buzz. Mine has the Fender speaker in it (not sure what it is rebadged).

I've changed one of the valves on mine to give me more clean headroom and I still get the buzz.

I've just picked up a blues Deville USA 1980's amp  4x10 so I'm going to try the same amp settings and see if I get anything similar.

The Fender speaker is an Eminence, although as they do OEM speakers they could be unique to Fender.

Buzz/ rattle in combos can be a real s*d to track down, ie it can take ages. It can be something trivial, such as speaker bolt rattling, or it can be electrical. Putting a 40W 1x12 combo in small box is asking for trouble....

[jpfamps]

Thanks again.

Its a Ltd version and is four years old. Jensen R1s were the original speakers.

Can I safely remove the Chassis to get at the top speakers and not be at risk from the charge that may be held in the amp.

I would like to get the amp back to working properly again. Perhaps I should just get it looked at by a good technician.

There could be charge held in the main filter caps. If you turn of the amp off using the mains switch leaving the standby switch in play mode the charge will drain in most Fender amps; however I not 100% sure it will in your amp, so if in any doubt about what you are doing DON'T REMOVE THE CHASSIS.

Having said that, I would suspect it is quite unlikely that the remaining Jensen speakers in your amp are the problem.

When you say phasing of the two speakers, what exactly does that mean.

Applying a DC voltage across a speaker terminal will either cause the cone to move out or in. In a multi-speaker set up you want all your speakers moving in the same direction, ie in phase. Although most speakers are wired the same way, there is no standard for speaker wiring so it is best to check when you mix speakers that they all display the same phase relationship.

To check speaker phasing I use and 9V battery (an old one will be better as it can deliver less current) and put this across the speaker terminals. The speaker will either move in or out. Check all the speakers using the battery the same way around. They should all move in the same direction. If they don't you will need to swap over the leads going to the speaker terminals.

Out of phase speakers will cause bass cancellation, so it's unlikely to be the problem with your amp.

Would mixing ceramic and alnico speakers have a dramatic effect.

Not sure how to answer!

Many amp manufacturers have successfully used Alnico and ceramic magnets speakers combined.

There is more more to speaker design than the magnet type though.