Anyone build an Orange?

[EdsBenedict]

Eds

Yes I would! A 72 model is about the model I'd like to build. I'm going for a 50 watter with 2 EL34's.
So questions:
Could you get voltages for the plates and screens?
Is the FAC after the first gain, tone stack and second gain stage?
Is there a choke in the boost circuit?

Thanks much...

Ha, that's exactly my plan as well - a OR120 but at 50W for earlier breakup, but with the same bass response. Once I get the thing open and a voltmeter ready, I'll get those voltages. You might need to give me a bit more info on a choke though - I've not built an amp with this and not sure what it is.

I believe that on this model, the FAC is between the first gain stage and the second. Apparently they did make later versions where it was after the second gain stage, but this makes the FAC slightly weaker in operation, which is a shame, though I've not verified this yet.

I would agree that the FAC with the given values gets too thin too quick though - I'll definitely be putting in slightly less of a transition.

Will be getting my workshop set up this weekend and will come back with some more data then.

[rp]

Will modern El34's handle that 500Volts??!! Or do I have to start saving for Mullards now...
To my daughters, "no college for you girls, I need Mullards!" LOL...

You could always give them each a killer Orange clone and a nice ES335, maybe that will convince them

I'm sure people here have old Marshalls, Hiwatts, Oranges running +500V. Maybe they'll chip in about what modern tubes they're having success with. I bet you could run modern tubes, at 20mA

[JoeCon]

rp

Oh yeah 335! I want one. I've had Les Paul's Customs and 3 pickups and standards, SG Les Paul's and SG's, Flying V's and Firebirds but never an ES 335...yet!!

As far as tubes go I guess we'll see how modern tubes hold up. Lets see what Edcor has for a 360-0-360 PT.

Thanks...

[JoeCon]

eds

No rush I'm just in the planning stages and don't have a blank chassis yet.
Looks like there were two chokes on the Orange. First looks like a small transformer mounted on the chassis. It's in the B+ supply to smooth ripple. But there is another small inductor mounted on the circuit board too and looks to connected to the boost circuit.

We'll figure this all out as we go along, and Welcome!!

[rp]

Lets see what Edcor has for a 360-0-360 PT.

180-0-180 w/ FWB

[xtian]

Can the full-wave bridge in this schemo be right? Usually all the diode anodes point toward HT, and the opposite end is grounded, and AC input is on the remaining two points. This schemo has the diodes rotated 90 degrees. Mistake?

[xtian]

Here is another version with the FWB the "right" way around:

http://www.webphix.com/schematic%20heav ... _or120.pdf

Another thing caught my eye: the PT secondary CT goes to a point BETWEEN the two reservoir caps (the two in series). What's that about?

[rp]

I'm not sure about the diodes either now that you point it out. But I did figure out that the power supply is a FWB Voltage Doubler. I had pdf'd this but luckily here's the link:

http://metroamp.com/wiki/index.php/Full ... ge_Doubler

[eddie25]

eds

No rush I'm just in the planning stages and don't have a blank chassis yet.
Looks like there were two chokes on the Orange. First looks like a small transformer mounted on the chassis. It's in the B+ supply to smooth ripple. But there is another small inductor mounted on the circuit board too and looks to connected to the boost circuit.

We'll figure this all out as we go along, and Welcome!!

The small inductor is indeed part of the presence circuit. Some of the later ones have a boost without it. I think you can get a little board mountable one that works from AES.

As per the tubes handling 500V, it's all about the screens (feel free to see my transformer rant in garage talk). I would consider SED, JJ6CA7, JJE34L, (also had decent luck with Valve Art at high B+). Avoid EH like the plague. I would also just consider going lower on the voltage, but do whatever you gotta do.

The center tap to the series reservoir caps is something that you see on 100 watt Marshall's as well. I have heard that it essentially balances the voltage on the caps without the typical balance resistors. Maybe there is more to it than that though.

[JoeCon]

The reason I'd go with a more conventional (Ken Fischer TW) type power supply is cost. 100uF 450 volt caps are $25 bucks each which is way out of this "cheap yankee" price range. I was thinking something more along the lines of the express supply which I can manage $$ wise.

[John_P_WI]

Joe, If you get creative you can use radial caps similarly to Dumbles precision power supply (OK after the first "axial" stage in the Dumble).

Here is an example of 450v x 100 u for a little more than $4:

http://www.mouser.com/ProductDetail/Nic ... pDMzs8o%3d

[JoeCon]

John

So how do you mount those radials, laydown on the board? I guess if they're not too tall they could stand up??

Thanks....

[John_P_WI]

Yes to both. I usually put them on a small board, standing up IF the height is available. Some guys glue them on their side and zip tie the bundle to a board.

You can also use smaller valued caps, but more of them in a series / parallel fashion to get nearly any voltage / uF rating needed. Like anything, just make sure you use bleeder / balancing resistors IF you have a group in series.

[rp]

So how do you mount those radials

This might interest you. I had a post on these but I can't find it as my foresight lacking two character handle makes search impossible:

http://www.ebay.com/itm/DIY-PCB-Cap-boa ... 2318eb16a7

These would open up a world of caps. Panasonic TC types come in 450V values are are supposedly hot sh*t, a hifi crowd fave. Snap mounts tend to be small, inexpensive and easy to source from non-boutique/specialty dealers ie Mouser, Digikey etc. I think I will go this way soon. I also don't think there'd be much trouble using radial leads and soldering them into those boards but best check the spacing specs.

BTW check out the other boards from his ebay store, others here described him as an old timer with a good rep, but I can't say. His page:

http://www.pmillett.com/

Damn, I feel Like I'm getting ready to build an Orange, already checked on these. TAG = vicarious amp thrills.

http://www.edcorusa.com/p/718/xpwr117
http://www.edcorusa.com/p/703/xpwr105

BTW there's al sorts of cool boards on ebay, mostly from China, anyone here ever try any? Legit? Fast? Here's a nice option for a TW:

http://www.ebay.com/itm/1PC-FR4-Power-F ... 4abe3a2f4a

[JoeCon]

rp

What's funny is work for Panasonic yet can't get those caps!! In fact even with my employee discount Panasonic Plasma TVs are cheaper at Best Buy!! But I will check those out...