Schematic for Orange AD140B?

[Crnovak]

Hello:

I am working on building my own tube amp and am looking for a schematic for an Orange AD140B. I have seen schematics on AD140TC, but want to see the changes for the Bass frequency.

Any guidance, direction would be most appreciated.

-Craig

 

[BassmanPaul]

Building a tube amp from scratch is not something to be attempted lightly. You will need a suitable chassis, nuts and bolds, rivets, knobs. you will need some means to mount the components all of which you will need to acquire. Transformers, tubes, sockets not to mention suitable connecting wire. You’ll need a soldering station, test equipment, experience in building such a beast and dealing with lethal voltages. You could well end up with an unstable mess. There really is more to it that a simple schematic.

May I humbly suggest you try something simpler such as a single ended Class A amp with about 5W output. If you have success you can move on to something slightly more powerful such as a Push Pull amp with about 15W out. These lesser builds will offer you an excellent education and experience into tube electronics.

 

[Crnovak]

Bassman Paul:

All good advice and I have heeded this. Thank you. I have spent 2 years preparing, studying for my bass amp builds. I am in the dry lab part of my design and simply want to compare the Orange AD140b preamp circuits to others.

So if you or anyone else has the schematic for an Orange AD140B amp, please reply here or PM me.

-Craig

 

[Wasnex]

Bassman Paul:

All good advice and I have heeded this. Thank you. I have spent 2 years preparing, studying for my bass amp builds. I am in the dry lab part of my design and simply want to compare the Orange AD140b preamp circuits to others.

So if you or anyone else has the schematic for an Orange AD140B amp, please reply here or PM me.

-Craig

I doubt you will find an AD140B schematic as it was a custom shop amp sold in very limited quantities. The AD140B evolved into the AD200B. Basically the difference is the transformers and changing from 6l6 to 6550 tubes. See this page: 1999 – Custom Shop: Early Days – Orange Amps

There was a handwired MarkI and MarkII of the AD200B and you can track down some of the details on various websites regarding how the circuit evolved if you are interested. Perhaps you could devolve the MkIII back to the AD140. I believe the evolution to the MKIII changed the number of gain stages and added negative feedback.

Everything I have read suggests the MKIII sounds better despite being PCB construction. It's fairly easy to find schematics of the Mark III. Although low resolution, the official power amp schematic is here: [Invalid or Expired Link Removed] Please let me know if you find the other page(s) of the official schematics.

FYI The MKIII actually makes only about 165-170W clean and many people think this is due to the transformers. It's fabulous sounding amp, but both the preamp and power amp seem intentionally setup to easily transition into OD. It sounds nice clean too though.

Unofficial schematics for the entire amp are here:[Invalid or Expired Link Removed]

Working voltages with and without tubes can be found in this thread: [Invalid or Expired Link Removed]

 

[Crnovak]

Wasnex

Thank you for the response. I’m going to read through these. If I find something new I will send you any copy I can obtain.

Thank you again.

Craig