Re-Valving an Orange Bass Terror

[Happy Jack]

I don't do false modesty.

If I tell you that I have the DIY skills of Frank Spencer (ask your Mum) and the electronic engineering capability of Homer Simpson, then I'm not just looking for a cheap laugh ... I mean it.

If I can replace the valves on an OBT, then so can you.

[b][size=4]Why replace them?[/size][/b]

1. No one ever gets to turn the knobs above "nine o'clock" because the amp is so damned loud and the valves have so much gain.

2. No one likes using the [i][b]D.I. Out[/b][/i] facility because of the OTT gain which is too much for many engineers to deal with.

[size=4][b]Don't believe me?[/b][/size]

Here's a passive 1970's Maya P-bass (classic JapCrap) played through an OBT, DI'd into a Behringer 1604 desk, and then recorded by Line Out into a Zoom H2.

Desk settings throughout:





It's not too obvious from the photos, but the Mic Gain is set to Zero.

OBT on LOW gain:



[attachment=79254:Original_AX7_LOW.mp3]

OBT on MED gain:



[attachment=79255:Original_AX7_MED.mp3]

OBT on HIGH gain:



WARNING! You may wish to turn the volume down. That horrible overload is what came out. I did consider turning the amp down until it went away, but then decided that would defeat the purpose of the example.

[attachment=79256:Original_AX7_HIGH.mp3]


[size=4][b]Replace them with what?[/b][/size]

There's plenty of choice out there, but I've selected the next level down which is the AT7, offering roughly 2/3rds the gain of the AX7. There are plenty of ex-military AT7 WA valves out there at the moment.



Using these means that I will be able to continue playing in the event of a tactical nuclear weapon being detonated near the gig.

Edited May 7, 2011 by Happy Jack

[Happy Jack]

[color="#FF0000"][b]DOING ANY OF THE ACTIONS BELOW WILL INVALIDATE YOUR WARRANTY.

DON'T DO ANY OF THIS UNLESS YOU ARE COMPLETELY HAPPY ABOUT THAT.[/b][/color]

If you're going to write a Dummy's Guide, then write it properly. I'm making no assumptions at all about the reader's ability level.

[size=4][b]1. Make yourself safe. [/b][/size]

Switch off everything. Unplug everything. Have the right tools (i.e. a single screwdriver!) readily to hand.

[size=4][b]2. Remove the top casing. [/b][/size]

This is held in place by no less than 10 screws.

Three on the front:



Two on the R/H side:



Three on the back:



Two on the L/H side:



They will last have been tightened at the factory, so they may be slightly tighter than is desirable. Do NOT use just any old cross-head screwdriver, use one that fits perfectly. For the very first anti-clockwise turn, press HARD as you turn the screwdriver.

These screws are very small and very black, so there's no risk at all that you'll lose any/all of them, is there?

This is what white china saucers are for.

[size=4][b]3. Look at what lies beneath.[/b][/size]





Really nice piece of design, this. The only things you now have access to are the two things that you are most likely to need to change ... the valves and the cooling fan.

[Happy Jack]

[size=4][b]4. Remove the AX7 valves.[/b][/size]

The valves are protected by simple ally sleeves which plug in using the bayonet light-socket principle. Push down gently and twist anti-clockwise and they simply lift off.



The valves are seated in their sockets by a bunch of "pins" which you can't yet see.



Remove each valve by rocking gently from side to side while you pull upwards with some firmness. They WILL feel stiff and it WILL take about 10 seconds to remove each valve. It is perfectly OK to grasp any part of the valve that you can see.





[size=4][b]5. Check your replacements.[/b][/size]

My AT7 WA valves are fractionally more slender than the outgoing AX7 valves. Note that the AT7s are clearly branded, whereas the original fitment AX7s give no clue as to their origin.



[size=4][b]6. Fit your replacements.[/b][/size]

This is the exact reverse of removing them. Line the pins up exactly, push down carefully but firmly, keeping the valve upright throughout.



Put the ally sleeves back, again just as with putting in a bayonet-fitting lightbulb.



[size=4][b]7. Re-fit the upper casing.[/b][/size]

Place the casing back in position and check (visually) that the screw-holes all seem to line up.



Replace each screw in turn, working your way methodically around the casing, but DO NOT TIGHTEN beyond about halfway at this stage.

Once all 10 screws have been replaced, then work your way around again but this time taking them to full tightness. They do not need to be very tight, just enough to grip properly.

[size=4][b]8. Put the original valves somewhere safe.[/b][/size]

Like, for example, the original packaging for the replacement valves.

Don't forget to label them.

Edited May 7, 2011 by Happy Jack

[Happy Jack]

[size=4][b]Was it worth it?[/b][/size]

You tell me.

OBT with AT7 on LOW Gain:



[attachment=79263:Replaced_AT7_LOW.mp3]

OBT with AT7 on MED Gain:



[attachment=79264:Replaced_AT7_MED.mp3]

OBT with AT7 on HIGH Gain:



[attachment=79265:Replaced_AT7_HIGH.mp3]

At the risk of stating the blindingly obvious, no other changes were made whatsoever between this set of soundclips and the previous set, other than replacing the valves.

[ahpook]

brilliant - good set of instructions, served with a grin !

...not that i have a OBT. but i liked the guide

[steve-soar]

Outstanding work Private Jack.

[Dood]

Consider it pinned - This is a brilliant walk through!

[Low End Bee]

Good work HJ.


Apart from
"1. No one ever gets to turn the knobs above "nine o'clock" because the amp is so damned loud and the valves have so much gain."

Apart from me. 2pm on the precision and 11am on the Retrovibe......

Are there AX7's with more gain?

[algmusic]

Top thread mate..

I'm ordering some new valves tomorrow

Cheers

Adrian

[Happy Jack]

[quote name='Low End Bee' post='1225175' date='May 9 2011, 03:10 PM']Good work HJ.


Apart from
"1. No one ever gets to turn the knobs above "nine o'clock" because the amp is so damned loud and the valves have so much gain."

Apart from me. 2pm on the precision and 11am on the Retrovibe......

Are there AX7's with more gain?[/quote]

No ... but there are Barefaced cabs.

[silverfoxnik]

[quote name='Happy Jack' post='1223195' date='May 7 2011, 01:53 PM'][size=4][b]Was it worth it?[/b][/size]

You tell me.[/quote]
Yes; definitely!

A brilliant piece of work Jack and it just shows what improvements can be made if you have the wherewithall...

Nik

[KK Jale]

Nice work, Happy Jack.

Good advice about using a precisely-fitted crosshead screwdriver to remove the amp cover. The screws on mine were incredibly tight. In the end I had to lay the amp down, use a socket set with a foot-long extension and apply all my weight… that did it. Just!

One more idea, especially if anybody chooses to use secondhand replacement valves (though I used a new Sovtek for V2 I robbed a lovely General Electric 12AX7 from my Fender amp for V1). On removing the Chinese originals, lightly press the nine pins into a soft surface (eg plasticine) and check that the pins on your replacement line up perfectly before inserting. If not, tweak them carefully into shape with needle-nose pliers. Bending the connections on the TB500's valve holders may (*probably will*) necessitate entire circuit board replacement!!

I bought this 80mm PC fan – [url="http://www.quietpc.com/gb-en-gbp/products/casefans/x-rw-80r"]http://www.quietpc.com/gb-en-gbp/products/casefans/x-rw-80r[/url] - to reduce noise but my tech advised that at 19CFM it didn't push as much air as the original so we left the old one in place. A 30CFM fan would be better.

[algmusic]

[quote name='Happy Jack' post='1223195' date='May 7 2011, 01:53 PM'][size=4][b]Was it worth it?[/b][/size]

You tell me.[/quote]

Top Top thread, mate. I've just re-valved my Terror Bass and your idiot guide helped this idot.. infact the TB sound even better than before including solving the DI problem without a 40db in-line attenuator..

Got some lovely new valves from watford valves.. nice guys there tooo.. :-)

[Chest Rockwell]

[quote name='Happy Jack' post='1225339' date='May 9 2011, 05:41 PM']No ... but there are Barefaced cabs. [/quote]

I have BF's and an OTB. i dont get the joke

[Happy Jack]

The only reason Low End Bee can turn his OTB up so high is because he [i][b]doesn't[/b][/i] have a Barefaced cab.

Rather than buying some AX7s with even higher gain, what he needs is a louder cab.

Like a Barefaced.

Like most attempts at humour, it doesn't really work when you have to explain it.

[waynepunkdude]

[quote name='Happy Jack' post='1228261' date='May 11 2011, 11:40 PM']The only reason Low End Bee can turn his OTB up so high is because he [i][b]doesn't[/b][/i] have a Barefaced cab.

Rather than buying some AX7s with even higher gain, what he needs is a louder cab.

Like a Barefaced.

Like most attempts at humour, it doesn't really work when you have to explain it.

[/quote]

[Sibob]

Cheers for bumping this, gonna get on top of this ASAP!

Did I see mentioned that it also sorts out the issue with the DI?....am on my phone so haven't read the whole thing yet.

Si

[Happy Jack]

[quote name='Sibob' post='1228465' date='May 12 2011, 09:49 AM']Did I see mentioned that it also sorts out the issue with the DI?....am on my phone so haven't read the whole thing yet.

Si[/quote]

Yup. All the soundclips in this thread were through the DI, so you can hear just how much it has been tamed by switching to AT7's.

The new valves make an already-great amp even better.

I was in Denmark Street yesterday talking to the nephew of the guy who owns Orange (and who is the main London distributor for their stuff) and he accepted that the original-fitment unbranded Chinese valves have been letting down Orange kit recently. They're in the process of shifting to noticeably higher-quality valve suppliers, I gather.


[color=#ff0000][b]THREE YEARS LATER - EDIT (25 Feb 2014)[/b][/color]

Dannybuoy has just posted this on another thread:

http://basschat.co.uk/topic/230604-orange-bt500-bass-terror/page__view__findpost__p__2379120

Now [i][b]that's [/b][/i]an interesting addition to this topic ...

Edited February 25, 2014 by Happy Jack

[algmusic]

[quote name='Happy Jack' post='1228471' date='May 12 2011, 09:53 AM']Yup. All the soundclips in this thread were through the DI, so you can hear just how much it has been tamed by switching to AT7's.

The new valves make an already-great amp even better.

I was in Denmark Street yesterday talking to the nephew of the guy who owns Orange (and who is the main London distributor for their stuff) and he accepted that the original-fitment unbranded Chinese valves have been letting down Orange kit recently. They're in the process of shifting to noticeably higher-quality valve suppliers, I gather.[/quote]

+1.. worked a treat for me also

[Happy Jack]

Excellent - the best way to have your efforts checked is for someone else to do the same and get the same results.

[Chest Rockwell]

[quote name='Happy Jack' post='1228261' date='May 11 2011, 11:40 PM']The only reason Low End Bee can turn his OTB up so high is because he [i][b]doesn't[/b][/i] have a Barefaced cab.

Rather than buying some AX7s with even higher gain, what he needs is a louder cab.

Like a Barefaced.

Like most attempts at humour, it doesn't really work when you have to explain it.

[/quote]

ah, thanks for the explanation anyway i thought i'd failed some bass guru 101 for a minute!



any chance of a coupla links for these AT7 WA valves? im not versed in such technicalities and googling brings up all kinds of things except 'buy here for £X'.

Incidentally I n00b goofed at a gig recently and didnt have a speakon-jack lead/adapter for the supplied cabs, so the soundguy DI'd the OTB. it sounded like farting. I imagine that is the issue you guys are talking about? he added some gizmo to the connection and it became more usable. I only heard enough to play with through the monitor but the audience assured me it was Big, Warm and Fuzzy, as is my intention.

[Chest Rockwell]

double post :|

Edited May 12, 2011 by Chest Rockwell

[algmusic]

[quote name='Chest Rockwell' post='1229005' date='May 12 2011, 04:43 PM']ah, thanks for the explanation anyway i thought i'd failed some bass guru 101 for a minute!



any chance of a coupla links for these AT7 WA valves? im not versed in such technicalities and googling brings up all kinds of things except 'buy here for £X'.

Incidentally I n00b goofed at a gig recently and didnt have a speakon-jack lead/adapter for the supplied cabs, so the soundguy DI'd the OTB. it sounded like farting. I imagine that is the issue you guys are talking about? he added some gizmo to the connection and it became more usable. I only heard enough to play with through the monitor but the audience assured me it was Big, Warm and Fuzzy, as is my intention.[/quote]

I paid £25 for both (I think) via Watford valves, ask them they are very good. I actually got mine the next day even though delivery is a couple of days

Edited May 12, 2011 by algmusic

[Chest Rockwell]

cool thanks! think I'll give it a go. thanks to the OP too

[vocrockguitars]

[quote name='Happy Jack' post='1223094' date='May 7 2011, 12:37 PM']I don't do false modesty.

If I tell you that I have the DIY skills of Frank Spencer (ask your Mum) and the electronic engineering capability of Homer Simpson, then I'm not just looking for a cheap laugh ... I mean it.

If I can replace the valves on an OBT, then so can you.

[b][size=4]Why replace them?[/size][/b]

1. No one ever gets to turn the knobs above "nine o'clock" because the amp is so damned loud and the valves have so much gain.

2. No one likes using the [i][b]D.I. Out[/b][/i] facility because of the OTT gain which is too much for many engineers to deal with.

[size=4][b]Don't believe me?[/b][/size]

Here's a passive 1970's Maya P-bass (classic JapCrap) played through an OBT, DI'd into a Behringer 1604 desk, and then recorded by Line Out into a Zoom H2.

Desk settings throughout:





It's not too obvious from the photos, but the Mic Gain is set to Zero.

OBT on LOW gain:



[attachment=79254:Original_AX7_LOW.mp3]

OBT on MED gain:



[attachment=79255:Original_AX7_MED.mp3]

OBT on HIGH gain:



WARNING! You may wish to turn the volume down. That horrible overload is what came out. I did consider turning the amp down until it went away, but then decided that would defeat the purpose of the example.

[attachment=79256:Original_AX7_HIGH.mp3]


[size=4][b]Replace them with what?[/b][/size]

There's plenty of choice out there, but I've selected the next level down which is the AT7, offering roughly 2/3rds the gain of the AX7. There are plenty of ex-military AT7 WA valves out there at the moment.



Using these means that I will be able to continue playing in the event of a tactical nuclear weapon being detonated near the gig.[/quote]
Cool clips. Tungsol 12AX7 are super for Bass really low microphony and good bass extension and generally slightly lower on gain than EH or JJ. Also worth trying EH 12AY7. Really smooth tube gain of around 50.