Laney R4 Bass amp

[N Cook]

First thing to say is anyone finding one of these, put some fine mesh under
the top grill which lies directly over the power amp.
A small piece of wire has dropped in this one and half blown the amp.
Anyone familiar with SK ,Sanken SAP 15 NY and SAP15 PY
or SAP15N and SAP15Y
according to Sanken datasheet , in English,
h1-o03ea0-TR.pdf
150W, 15A, 160V bipolar with temp compensation

 

[N Cook]

First thing to say is anyone finding one of these, put some fine mesh under
the top grill which lies directly over the power amp.
A small piece of wire has dropped in this one and half blown the amp.
Anyone familiar with SK ,Sanken SAP 15 NY and SAP15 PY
or SAP15N and SAP15Y
according to Sanken datasheet , in English,
h1-o03ea0-TR.pdf
150W, 15A, 160V bipolar with temp compensation

Avoided the Flash crap on the Laney site by going off Google and downloaded
the R4 schematic.
There is another major flaw with the production of this amp.
The 4, 0.22 ohm ,emitter resistors are on end and one end soldered right
down on the board. Not failed welds so 5W must be the right rating but
vibration is causing the resistor lead to progressively fail at theis
juncture of the component side of the pcb and the flaring , over the lead,
of the ceramic covering of the resistor.
Other than replacing these with ceramic cup standoffs - does anyone coiver
the leads with silicone sleeving and tie them all together to stop any
rocking or any othe rideas?

 

[roundozo]

Hi All,

Does anybody know where I can find the schematic diagrams for the Laney R4? Some unexpected liquids went down the vent at the back right onto the board. I immediately turned it of and took the panel off. I then dried up all of the liquid and did not use it for another week so any excess remaining could dry off. A week later I have plugged it back in and turned it on. All seems to be fine until you try and play the bass. The amp is picking up the bass but nothing is coming out of the speakers. I have got a friend who is pretty handy in this area and says he might be able to fix it if he were to get hold of a circuit diagram. I've looked everywhere but had no luck. If someone could point me in the right direction I would be very grateful.

Cheers,

George.