Orange amp build

[dearmond]

Hello!
I've been thinking of building a bass amp for my nephew and thought the Orange AD200 Mark3 looked good. It seemed to have good reviews and from the schematic, it looks interesting and fairly straightforward.
However, the only PT/OT transformers I could find to match this are from Mercury which are very pricey.
Can anybody suggest some alternatives?
Also, any tips on this build?

Thanks!

[eddie25]

You need a tranny with dual HV so you can get almost 700VDC on the plates and closer to 450VDC on the screens. MM is gonna be your best bet most likely unless you get one custom made.

Which schematic do you have? The official one from Orange, or the one floating around the net? The non-Orange one is slightly more accurate I think, it has one missing resistor and a correct cap value that the Orange doesn't.

[jon]

I'm following closely.

Have you looked at calling Phil at Heyboer. I had a one off made a year or so ago that cost about $150.00.

[M Fowler]

I would get the data needed for the PT and OT and call Heyboer or checkout Edcor if you do not want to go with MM.

[Giaime]

I have the AD200 MK3 on the bench now for a friend, I don't think it's a great amp. Yeah it can make dirty bass sounds, but cleans are not great and not available at high volumes. This is also because stock output transformer isn't great.

I would suggest to go to the Ampeg route, maybe a classic SVT preamp with a 4 x 6550 output stage instead of 6 x 6550...

[dearmond]

I think it's the non-Orange schematic. Got it from a post on one of the Bass Guitar forums. I'd call Heyboer if I can get the specs. I had them build me a transformer in the past at a good price and it is great. I've been digging around for specs but up til now I haven't found any.
I've looked into the SVT and looks like way too much for what I want to do.
This is the first I've heard of Edcor. I'll have to keep them in mind.

Thanks!

[selloutrr]

try contacting Matamp or Green Amps for a PT / OT

[selloutrr]

https://tubeamparchive.com/viewtopic.php?t=14128

[eddie25]

From what I remember the PT is dual primary also. It has 4 secondary taps as you've probably seen on the schematic. Plates, screens and preamp, bias, and heaters. I think the heaters were the only one with a center tap. Does your schematic have voltages? I also think the OT measured just under 1400 on the primary.

[dearmond]

Thanks selloutrr. I'll keep your info on hand.
Eddie25, the schematic did not have any voltages. You are right about the PT. Also, your estimate on the OT would sound about right.