Hi all,
I have Spark 550 with 300b push pull.
Power tubes is 300b with 2 pcs 12AX7 and 2pcs 12AU7 for the driver.
Today, my amp is dead. Both channel are not working.
Some of the trouble shooting I made:
1. Filaments are working. All power tube and driver tube are glowing.
2. High voltage rail for power tube is working. Tested between plate and ground is around 360 Volt on both channel.
3. Driver tube voltage rail, no problem.
4. Tube replacement on both left and right.
Anybody has the schematic for this beast?
I also thinking to rewiring this old amp into new one.
Anybody has a schematic for 300B pushpull?
Thank you in advance.
I have Spark 550 with 300b push pull.
Power tubes is 300b with 2 pcs 12AX7 and 2pcs 12AU7 for the driver.
Today, my amp is dead. Both channel are not working.
Some of the trouble shooting I made:
1. Filaments are working. All power tube and driver tube are glowing.
2. High voltage rail for power tube is working. Tested between plate and ground is around 360 Volt on both channel.
3. Driver tube voltage rail, no problem.
4. Tube replacement on both left and right.
Anybody has the schematic for this beast?
I also thinking to rewiring this old amp into new one.
Anybody has a schematic for 300B pushpull?
Thank you in advance.
I don't have the schematic.
That's what I am looking for to fix this beast. Too many good component will be wasted if I scrap this amp.
That's what I am looking for to fix this beast. Too many good component will be wasted if I scrap this amp.
If no one has a schematic, then if the amp does not use a PC board,
you should do some wire tracing and draw out the schematic yourself.
It might be harder to do if most of the parts are on a PC board, especially if it is a multilayer board.
But if we can see the schematic, troubleshooting will be easier,
And ... we may be able to make the amp more reliable (so as not to have to fix it again).
you should do some wire tracing and draw out the schematic yourself.
It might be harder to do if most of the parts are on a PC board, especially if it is a multilayer board.
But if we can see the schematic, troubleshooting will be easier,
And ... we may be able to make the amp more reliable (so as not to have to fix it again).
A customer currently brought in on if these amps in for repair have you checked the voltage on the center tap of the output transformer it's the red wire on the OT if there is voltage is low check the time delay relay that is located in the middle of the amp you need to remove the bottom cover
- Status
- Not open for further replies.