Orange AD140B - Hand Wired All Valve Head £1250

[dustandbarley]

Rare Orange AD140B Bass Amp which I've owned from new - #008 of 17. 

A couple of small tears in the tolex but good condition for age.  I've owned this for a couple of decades and I love it! but I now have to use more portable gear so sadly this lovely amp has to go.  Collection only as it's heavy and I'd worry about the valves.

Located in Ashford, Kent.  Any trial welcome.
Please check out the planetofamps  link for great in-depth info about these amps:-
 

http://www.planetoftheamps.com/orange-ad140b.html

Here is a 'favourable’ links on Reverb.com although it seems a tad optimistic:-

https://reverb.com/item/14181787-orange-ad140b-bass-amp-1999-limited-edition

Thanks for looking, here are some pics:-

Edited March 2, 2019 by dustandbarley

[dustandbarley]

Back up for sale - BUMP

[Sparky Mark]

Sorry to be thick but it looks like this can operate at 2, 4 and 8 ohms output? Have the valves ever been replaced? I also know nothing about how valves are biased but the photos in that link don't show any trim pots or devices that would allow bias adjustments?

[dustandbarley]

An interesting question to which I'm afraid I have no idea of the answer. The amp had 4 new 6L's valves in May 2018.  This work was carried out by John Rigg in Whitstable and these new valves replaced the original valves after 2 decades of fault free service.  I called John and he said he'll look up the wiring diagram and let me know about the trim pot, otherwise if the bias needs adjusting he would have done it by changing some resistors and this was quite a routine thing to do for this kind of amp.

I'll let you know more when I hear back.

The speaker outs are 2 x 4 ohm and 1 x 8 ohm.  I'm not sure you could run 1 x 2 ohm cab, but quite a few options of 4 and 8 ohm cabs.

[dustandbarley]

Here's what John Rigg says about the bias...

Hi Justin,

A quick web search for the AD140 Bass schematic reminded me why I
don't have it. I could only find the AD140 lead amp schematics online,
which are different. I'd have to contact Orange, but as it was a
fairly simple circuit I didn't bother at the time.

I can't remember if the bias was adjustable on this particular amp,
but most of the Orange amps I've worked on did have adjustable bias. I
would definitely have checked it and adjusted it if necessary, either
by adjusting a pot or altering resistor values if there wasn't a pot.

A general point: someone who doesn't know much about valve amplifiers
shouldn't be fiddling around inside one due to the potentially lethal
voltages, which are quite a bit more dangerous than mains voltage.
Also the consequences of getting the bias wrong could be expensive
(burned out valves and/or output transformer).

Regards,
John

 

[Sparky Mark]

Thanks Justin. Totally agree with John's comments; there's no way I would attempt any maintenance on any amp, let alone a valve beastie. I was more interested to find out how simple a valve swap would be for a tech if and when the time came. If your new set lasts as well as the originals that'd see me out.

The question about impedance wasn't so much about using 2 ohm cabs, rather that you could connect a 4 ohm load ( one 4 ohm or two 8 ohm cabs) to each of the two 4 ohm outputs. Those outputs give loads of options.

[dustandbarley]

Yes, so 4 x 8 ohm cabs connected in pairs to the 4 ohm speaker outs works fine. IIRC the outputs were like this so you could use a pair of 8 x 10 cabs.......

Edited September 4, 2018 by dustandbarley

[dustandbarley]

BUMP

Edited March 2, 2019 by dustandbarley