66 bassman for bass?

[robertneagle]

have been using a 66 bassman head w a peavey 2x15 cab for bass. once volume gets to about 4 or 5 it starts distorting kinda bad. is this common? if not is it the head or cab? would taking the head off of the cab and reducing the vibration help? is it normal to hear a kind of ringing when tapping on head at decent vol? seems like this is not a popular amp set up for bass but it sounds sweet w exception of the distorting at mid to upper volumes. any suggestions on gettin rid of dist/ more vol?

[Chuck H]

That amp isn't going to have the volume or headroom of a modern bass amp. When it was made there was leeway built into the volume control so you could amplify even very low input signals. As a result there isn't much headroom ON THE KNOB. The amp IS putting out it's maximum watts though. This is evindenced by the fact that it won't get any louder as you turn the volume up higher, only more distorted.

You may be able to get more volume from it though. I'm going to speculate that it's in need of service and probably tubes. The ringing when you tap on the amp is likely a microphonic preamp tube but it could actually be one or both of the power tubes. Also, if the power filters haven't been replaced then it's long over due. Servicing the amp should involve checking and replacing any bad tubes. Power tubes should be replaced as a set. Replace power filter capacitors if they are very old. DO replace the bias circuit caps and any electrolytic caps in the preamp also if they are old. Check and replace any old resistors that may have drifted over 20% off spec. Clean and retention jacks and tube sockets.

The amp is 44 years old. Not many modern amps will last that long as they were built. Your amp can play like new with a little TLC and you should notice an increase in performance.

Chuck

[Gibsonman63]

1+ for Chuck's comments. My bass player uses as silverface 50W bassman for my Thursday session at the icehouse and it works much better than I would have thought and we crank it up fairly loud. I believe that he adds some clean boost to the front end with his wireless, but I would think an LBPB would work just as well if not better. We are playing Skynyrd, ZZ Top and Trower type stuff and he punches through the mix just fine with an EB0, but of course we aren't doing any crazy dropped tunings. Once you have the maintenance done that Chuck recommended, invest in good tubes. You can order matched power tubes that will break up later and give you more headroom.

The other Bassman trick is to jumper the two channels. Set the channel with the deep switch to cover the bottom end and add the other channel add definition and attack.

[robertneagle]

thanks

apprieciated!

[robertneagle]

how exactly do you do that?

[robertneagle]

& if i leave it at 4 & use something up front(w a lil xtra gain) might that be cleaner?

[Gibsonman63]

It is possible, but if you are still running with the original electrolytic capacitors, servicing the amp will get you a lot more headroom and total volume than pushing the front end harder. The added benefit is that you will increase the reliability of your amp.

If you have a clean boost pedal or a compressor with level control, experiment, but if you are going to spend money, I would put it in the amp first.

Also, if it hasn't been done, change out that two prong plug for a grounded three prong plug. Search the forum. There is discussion ad nasium on grounded cords, death caps etc... Keep the original in case you want to sell to an anal retentive collector later.

[robertneagle]

I also get that noise every now n then that corrects w a good whack to the side. So what do you think it would cost roughly to do all this? I do have a lil exp w electronics but aside from changing the cord( which I did a few years ago) I don't mess around in there. Know of any good techs in New Orleans area?

[loudthud]

You should verify that the speaker cab is in good working order. Verify that it is a 4 ohm cabinet and that both speakers are working.

[olddawg]

You should find a big cheap old Peavey bass amp to go with your cab to play your bass and let your guitar player use the Bassman through a 4X10 cabinet. I can smell the OT dieing from here.

[robertneagle]

Ot dieing?

[Gibsonman63]

Sounds like some leg-pulling with a tinge of jealousy to me. They do make great guitar amps though. I wish I still had mine

[robertneagle]

ot dieing?

[olddawg]

ot dieing?

It's much too desirable as a guitar amp to cook the OT when you push it to the limit with old tubes and caps to try to force it to be a usable bass amp.

[Groover]

OT = output transformer, I would guess dieing = dying

The implication being that you will stress the output transformer if you are trying to use this amp for bass in a fairly loud situation. But I do think it was mostly leg pulling as Gibsonman63 suggested. These old Fenders are pretty durable, provided they are maintained.