ANY IDEA OF MY PRODUCTION YEAR?

[BLUES HARP MAN]

THIS IS MY OR-120 AMP S/N 12004



I bought this amp at a "High-Fi" electronics store back in the early 80's. I got a good deal on it and I had them put new "finals" valves in it. The valves are LINDAL "TUBE 5".

I did a bit of study on LINDAL-- Here is what I found out --

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LINDAL - ITT - RTT



Notice the similarity in the boxes and layouts. These tubes came from the same low price tube house that purchased them from wherever they could. Initially they were branded ITT (International Telephone & Telegraph), and then they changed to Lindal. At some point they were labeled RTT. I don't know what the 'R' stood for. Matter of fact, I'm not even sure the 'TT' portion meant Telephone & Telegraph as it did with ITT. Why did they change from ITT? ITT had name recognition. Who the heck was Lindal? Perhaps they just lost the license to use the ITT name.

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Just saw your page on Lindal tubes.
Since I worked for them I can tell you what the Boxes mean.
They bought the rights and inventory for ITT tube in the 60's.
They could use the ITT boxes as long as the original inventory lasted.
They started to change to RTT, Radio TV, Tube, but went with just the name Lindal.
Lindal was the mail order part of one of the largest tube wholesalers in the country and supplied tubes to every major tube co.
None of the major tube companies G.E., RCA, etc, made every type and they bought and sold to each other.
Lindal got out of the tube business in the late 80's but the principals are still in the transistor business today.

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This above came from this site--

http://www.geocities.com/rxtxtubes/pa02001.htm

About Pax Comm

The nickname PAX-COMM and the name PATUXENT COMMUNICATIONS were established in 1975 as the Two-Way Radio, Communications and Industrial Electronic Service Division of
THE PAX-TRONIX CORPORATION.
PAX-TRONIX opened in 1972 as PAX-TRONICS. We incorporated and changed the spelling in 1975 when PATUXENT COMMUNICATIONS was created as a division. THE PAX-TRONIX CORPORATION was disestablished and closed in 1995.
PATUXENT COMMUNICATIONS remained in operation providing repeater services and electronic sales and maintenance services to a small business clientel. In late 1998 the repeater systems, assets and customer base were sold, but the business name retained. In early 1999 we began buying tubes from closed businesses (including buying back our own tube stock) for the sole purpose of setting up this Internet Sales site.
I also haunt yard sales, antique shops and other places for good deals on parts and equipment. I test, repair and calibrate/qualify the equipment. I catalog the equipment and parts and offer them for sale at very good prices.
So here we are! This site is rapidly expanding!

and on that site I found these links to other Valve sites

http://www.michelletroutman.com/tubes.htm

http://www.tubecollection.de/

http://tone-lizard.com/Vintage_Tube_Boxes.htm

http://www.worldtubeaudio.com/directory/directory.htm

http://www.cs.helsinki.fi/u/oheinone/valves/

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I found the Valve sites to have some interesting information on them and thought we would share with ya all.

The Vintage Tube Boxes site had a lot of good info and photos.

[Simon Wicks]

I'd say based on the serial number, you amp is probably a mid 70's amp...around '75. As for the valves, Lindal was probably a rebrander. They would of bought tubes from a whole host of sources, stuck their own badge on and flogged them. They are probably some nice tubes.

What were the tubes? ECC83/12AX7 or EL34?

[BLUES HARP MAN]

Hi Simon,

I did not get the old ones back so I have no idea what were in there. I know they were soft and that is why I had the new ones put in and biased by that Hi-Fi shop.

All the Lindal tube has on it is "TUBE 5".

The sound is terrific from this amp. It has such good low end and the feedback control and sound produced is second to none!

[Andy H.]

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by BLUES HARP MAN</i>
<br />Hi Simon,

I did not get the old ones back so I have no idea what were in there. I know they were soft and that is why <b>I had the new ones put in and biased by that Hi-Fi shop.</b>

All the Lindal tube has on it is "TUBE 5".

The sound is terrific from this amp. It has such good low end and the feedback control and sound produced is second to none!
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">Hi BLUES HARP MAN. Welcome!

Yes the amp is likely a '75 build.
Orange amp timeline

Hopefully these valves will be up to the job. The OR120s do need strong valves as the amps hit them with unusually high voltages which kill cheap ones fairly fast. Good valves should last a good while though.

Not wanting to cast aspersions on Hi-Fi shops in general but they may or may not have had the specialist knowlege needed to bias up the amp properly. If they used the oscilloscope method you'll probably be alright, but the OR amps do need biased 'hotter' than most to avoid crossover distortion from biasing too cold. Oranges aren't quite like Marshalls and most other valve guitar (or audio) amps that way - see what current Orange designer Ade Emsley had to say on that in his second post HERE.

If it is sounding good then you are probably okay that way. Just check (in a darkened room after playing hard for 20 min of so) that there are no signs at all of 'red plating' due to too hot biasing.
RED PLATING

Thanks for the valve links. Couple of goodies there I hadn't seen.
The http://www.michelletroutman.com/tubes.htm link you gave doesn't appear to be working right now though.


Andy.

[BLUES HARP MAN]

Hi Andy,

Thanx for all the comments. 1975 must be right it also lines up with this chart I found here

http://users.telenet.be/orangefg/orange_page.htm

Hey the ADE post about bias and the comment on the 6L6 tubes made me think that that is what were in my amp because I remember at the time thinking hey that is real close to my Gibson L6S model number. I will have to check and see if I have the 470 ohm or 1000 ohm on the screen resistors.

I really like 6L6 tubes being I have had good luck in RF apps with them. I did a search at Wikipedia and found this--

==============================================


Variations

Early variations included transmitting tubes such as the 807 (1937), the smaller 6V6 (1937), the many KT versions marketed in Europe, and a subsequent vast array of audio and RF power tubes. One of the largest post-WWII applications was in the basic design of television sweep power tubes, starting with the 6BG6 (1946), a modified 807. TV sweep tubes were not replaced by transistors in earnest, until the 1970s.

Further testimony for this device's success would be even simpler: the 6L6GC version is still being manufactured and is used, primarily, in guitar amplifiers. Manufacture continues in Russia (2 factories), China (2 factories), Slovakia and Serbia. Thus, the 6L6 has enjoyed one of the longest active lifetimes of any electronic component at more than 70 years.

=========================================
I read all the red plate info too and the SV meltdown tube photo from red plate.

I have another problem with my amp and did a post in the tech section here

http://forum.orangeamps.com/viewtopic.php?t=19070

26 views but no reply as of yet. I sure would be interested to see what you, ADE and others think of this one--it has me in a quandary.

[Andy H.]

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by BLUES HARP MAN</i>
<br />I have another problem with my amp and did a post in the tech section here

http://forum.orangeamps.com/viewtopic.php?t=19070

26 views but no reply as of yet. I sure would be interested to see what you, ADE and others think of this one--it has me in a quandary.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">Spotted it. Might it be something to do with it being a dual ganged pot - two separate sweep tracks? Some were like that.

Other than that I don't know right now, but I am putting out feelers on that one. See if we can't come up with some more ideas.


Andy.