Notable exceptions to this trend are Fender, Peavey, Marshall, Traynor, Rivera, and for all I know others. If you know of an amp maker that supports the product with technical services and literature I would be glad to acknowledge that. After all, the motto we go by here is Joe Hammond's Maxim: "That crow don't taste too bad if you use enough salt and pepper."
There are two reasons, I think, for the lack of support. The first is to steer repair traffic to so called "authorized service centers". The second is, I think, to make the product as cheaply as possible and thus disposable, using a skeleton crew to distribute and merchandise the product.
This creates difficulties for people like me, because without schematics and a technical support department, the range of repairs I can tackle on such products is limited, and the amount of time figuring something out is expanded. It also creates some resistance because everyone who buys one of these turkeys (not naming names here) and has a problem past when the warranty expires ends up getting hosed and has to dump the former amp at fire sale prices. That is, by definition, someone who is a) not happy and b) will remember who screwed him or her.
I was recently repairing a Vox AC30C2, which is the latest iteration of the venerable AC30 amp. It's quite different than any Vox that preceded it because it uses a single circuit board, has a handful of ICs, no tube rectifier and the cabinet is made from MDF. Without a schematic you can't figure out what's going on in a month of Sundays.
Here's some correspondence:
I have a customer with an AC30C2 that needs repairs. Is there any chance of getting a schematic diagram for this amplifier?
2008 66th Street
Windsor Heights, IA 50324
Here's the answer I got.
Thank you for your inquiry. Schematics are only available for authorized Service Centers. If you would like to become a VOX-authorized Service Center, please contact our Customer Service department at (631) 390-6800 or email@example.com.
Product Support Specialist
(Monday through Friday, 1pm to 5pm Eastern Time)
So there you have it folks.