OT primary side reversed wires

[Emetal]

I have found out that the RED and BLUE wires on the primary side of the output transformer are switched, according to the schematics RED should go to the plates of V7 and V8 in reality it is going to V9 and V10. Same thing with the BLUE wire instead of going to V9 and V10 as per schematics, it is actually going to V7 and V8. Does this matter, should I correct this? I think I have read long time ago that this can cause weird sounds to appear??? The amp is Laney VH100R. The schematics is attached.

[The Dude]

If the wires were wrong, the amp would be oscillating because you'd have positive instead of negative feedback. If the amp has been working all this time, it's extremely unlikely it's wired wrong, unless someone replaced the transformer, wired it wrong, and you have an oscillation problem. If it's not broke, don't fix it.

[Emetal]

Well I started investigating OT because the sound is just not fat and big as I want it to be, all the measurements with DMM are OK, OT seems to have no issues, I just noticed that schematics is different so I thought I should ask..

[The Dude]

I've had factory OEM replacement tranformers be "wrong". For that reason, when I replace an OT, I don't trim the wires until I verify that it's wired correctly. You'll often find primary wires color coded differently/phasing opposite of what it should be.

[Jazz P Bass]

The only way to 'know' is to break the feedback loop. (R58 and the Resonance switch in the open position)

If the signal increases, then the wiring is correct.

[g1]

I would guess you may find the grid connections (P26 and P28) reversed as well.

[Emetal]

I would guess you may find the grid connections (P26 and P28) reversed as well.

Nope, those are like on the schematics, P26 is going to V7 and V8 and P28 is connected to V9 and V10

Anyway I just looked up photos of open Laney's on the internet, and noticed they all look like this one, so the factory simply does not respect the schematics color code..

[Chuck H]

Nope, those are like on the schematics, P26 is going to V7 and V8 and P28 is connected to V9 and V10

Anyway I just looked up photos of open Laney's on the internet, and noticed they all look like this one, so the factory simply does not respect the schematics color code..

Or,.. A shipment or two of OT's to Laney had the wire colors wrong and Laney just improvised. It happens.

[The Dude]

Or, as often happens, the engineers/designers drew the schematic based on parts they used to build and design the amp. Then, the bean counters found a cheaper source for the transformer for production models and the wire colors were different from that vendor.