BassmanPaul

Hello @Longwheelbass are you there??

I'm trying to help you here! 

I would eMail Phil and see what he suggests. It could be simply a bad power switch or some protection kicking in.

For interest how is the speaker connected to the amp?

Ampeg B15N is one of the best studio bass amps ever made.

I have yet to go to an open jam that didn't have a bass amp. Mind you I have lived in the Toronto area for the last forty years. Perhaps the UK is ahead of we yokels.

Far better than buying an EvoII head and not liking the results tha knows.

A 410 is not much smaller that a pair of stacked 15s. If you need less stage volume just use one 15. 

@Longwheelbass Do you hear a hum from the speakers?

In the very early Seventies The band I joined had bought a whole whack of Orange equipment. I played my bass through said amp and an orange 4x12. Handled it just fine though I was just using a four string Precision. How the set up would handle a five or six string bass I can't say. 

First question: Does it work with headphones?

mute switch is in the play position?

8 hours ago, Dan Dare said:

 

Spot on. It's why I take nothing for a headache (nothing acts faster than Anadin, after all)

Tylenol works, we swear by it.

Just for interest, when the amp is in operation do you see a faint blue glow inside the output tubes?

No argument here!!  Just move on. There's an old saying: 'None so queer as folk'.

The other side of the coin is that he may have had to deal with many similar calls from other potential buyers and was fed up with the whole sale.

That said, he should have been willing to supply the serial number of the unit he is selling.

Speak for yourself Joe!! LOL

I assume, being an Electrician, that you have a Digital Multimeter.

In case you are without:

bassman_135_sch.pdf

Simple cap discharger. Never short the caps to discharge them. Get a 10KΩ 2W resistor and two lengths of insulated wire. Solder a length of wire ti each end of the resistor and cover the whole shebang with heat shrink to insulate it. Connect an insulated Croc clip to each end and you have a cap discharger. Connect across the cap and it will quickly and safely discharge through the resistor. QED

Edit: I changed the resistor power rating because a 2W resistor has more robust leads so making a stronger assembly.

Thank you for dropping by Stuart. I'm certain that members will appreciate any information you can offer.

These amps have a very simple schematic - pretty much standard Fender through much of their tube offerings. For interest what seems to be the problem with the amp?

It can't be much good. Look it's full of holes!! LOL

Enjoy1

You must remember that 'volume' is logarithmic. This means that if you are wanting more volume, to get twice as loud as a 100W amp you have to increase power by a factor of ten. Thus a 1KW amp will only get twice a loud as a 100w amp.  Using that increase in power means that your speaker systems need to be able to use that power without failing. Their impedances would also have to allow the amp to supply it's maximum power.

The amp I use for my bass is a Class D Stereo power amp fed by a tube pre-amp I built for that purpose. My cabinets are Acme Sound B2 models. Impedance is 4Ω each. I connect them one each channel in a vertical 4x10 configuration. If I use all four of my cabinets, my amp will supply 1000W per channel at 2Ω. 

Which is why I quoted what I did!

On 06/01/2024 at 10:10, sandy_r said:

 

Both valves listed as 12AX7 (a standard valve ...but genuine parts preferred!) 🤔

 

Or ECC83 even 7025 which is a low noise version of the 12AX7..

On 07/01/2024 at 19:15, agedhorse said:

Try the valve before screwing with anything else. 

Good advice from an expert!  

When I was ready to order my Fretless the idea of that massive expanse of black ebony scared me so I had the fret lines put in. LOL

Now I don't even think about it and the bass has become my favourite.

MacGyver would be proud!

You saved me some money too 'cos I was considering buying the parts for you and shipping them to you at my cost. What's a couple of hundred bucks between friends. LOL