Bare Knuckle Pickups Forum
Forum Ringside => Tech => Topic started by: maverickf1jockey on March 10, 2008, 05:28:14 PM
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I have finally got round to replacing the valve that was going wrong in my TT after a sudden change in the tone prompted me to get off my arse and do something about it.
The trouble is that the change has not reverted to how it was; the sound is muddy and I'm not getting nearly enough gain.
I had replaced the dodgy valve with a JJ electronics valve, which as far as I can tell was the same sound as before the change of the valve.
Swapping the JJ round with the remaining Orange-branded valve has helped a bit but it still sounds like utter shite.
I have checked my guitar and my pedals; no problems.
Can you please help; I'm at wit's end.
The replacement valve was a dual triode model if that helps you.
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Did you set the bias when you fitted the new valve?
Also, I have on my Matamp LX a switch that switches the amp from pentode to triode - this makes the sound thinner and more fizzy so it may just be the valve you chose.
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How would one go about the process of biasing the valves? There is no evident way of doing so unless it is below the valve socket itself.
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You may wanna take this to the Orange forum- not that this place is without its amp gurus. Just a thought...
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I'm not a member of the orange forum; hell, it's hard enough to put in a showing here half the time. I am aware of the amp gurus resident here (along with a large group who own the TT) and that is why I asked here; I trust the opinion of people here as opposed to people I don't 'know'.
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I'm actually interested to hear about this too. Biasing amps is something I know zero about, and having a TT myself I think I should learn...
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It would appear solely from that comment we have much in common. Have an imaginary present from me to you :gif:.
Sorry about that Badgermark but I'm so anxious about sorting this I've been checking this thread for every 2-3 minutes and I'm going a bit strange...
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Interested in finding this out too for my TT
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Found this; http://www.orangeamps.com/forumtest/topic.asp?TOPIC_ID=14380 apparently doesn't need biased? Still makes no sense to me though.
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I also found an ebay guide on what valves sounded like what but it wasn't really in enough detail.
I would think it would be a good idea to do a total refit but the cost is not pretty.
If I could avoid JJ valves that would be good (although the shop I used, RS components, only do JJs.)
After a high gain sound with a fair bit of treble (but not Fender levels). Anybody got any recommendations?
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Why not JJ's where they the trouble?
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Because the JJ in V1 sounded the same as the busted original but was working perfectly well.
Also they only do one type of 12AX7 (the ECC83 S), which is not a high gain valve and is more useful in a HIFI application.
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Preamp tubes shouldn't need biasing, just the power tubes. How many tubes does the TT use? How long have you had it? If you've had it I while I'd suggest replacing all the tubes. I just did this with my Peavey Classic 30 and it fixed my problems I was having. If that doesn't solve it then you have a spare set of tubes and I would take it to a tech.
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I've had pretty good experiences with JJ's but they may not be what you're after. Perhaps you could try Electro Harmonix or something? I had a quad of those in a Laney GH50 and they improved the quality of the gain and reduced noise somewhat. If you look at the test reports at watfordvalves.com they may give you an insight into which valves are for you.
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Because the JJ in V1 sounded the same as the busted original but was working perfectly well.
Also they only do one type of 12AX7 (the ECC83 S), which is not a high gain valve and is more useful in a HIFI application.
JJ make the ECC803S which is their high gain 12AX7
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Because the JJ in V1 sounded the same as the busted original but was working perfectly well.
Also they only do one type of 12AX7 (the ECC83 S), which is not a high gain valve and is more useful in a HIFI application.
JJ make the ECC803S which is their high gain 12AX7
RS do not stock that one, I think. As far as I have read the '803Ss are purely reduced in noise and are still more at home in a HIFI.
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I have heard from several sources that the TT does not require biasing, it's self biasing.
My TT came with all JJ tubes (power and pre-amp). I put a Phillips JAN spec in the V1 position to brighten it up some as JJ's are a dark tube.
What worries me about your amp is that it's sounding worse than before your valve blew. I think the JJ's are darker than the Orange branded tubes, so I would expect the sound to be darker, but not muddier.
Do you know anyone with a spare you can borrow to try? It's not unheard of for new tubes to be faulty.
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I've found an ebay seller whom I think is respectable and they do EH valves. They sound like the sort of thing I'd be after and because the stock Chinese valves are not branded I can't gauge whether they have reliability issues.
A total revalve with EHs may well be in order...
They also had a tung sol and a couple of MESA branded valves but the MESAs, I would expect, are not as great as a third party brand and would be quite dark.
But the first order of business is, indeed, to work out why the sudden change in tone and why the lack of improvement. I was hoping someone such as HTH would pop up and give me a hand...
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The TT is cathode biased and does not need any biasing to replace any valve.
The JJ ECC83S is a standard ECC83/12AX7, and actually tests as one of the highest gain current production valves, so it should be fine. We use hundreds of them at Matamp, with no problems.
I've personally used plenty of EH too, so they should be fine. The differences between brands of valves can be said to be subtle tonal changes, not great/cr@p so I don't think that will be your problem.
The Original Chinese valves can almost certainly be improved upon.
If changing the valves (any and all of them, pre and power amp) doesn't restore the sound quality back to what it was, then you have some other problem. If you're confident enough, you can visually check the innards to see if there's an obvious visible fault, remebering of course all the usual warnings about capacitors storing charge after the amp has been turned off.
Beyond this you will need to take the amp to a tech. If you were anywhere near me (North Derbyshire) I'd have a look FOC. :?
Good luck.
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Cheers. I might just get a replacement from the same shop I bought it at as it should still be returnable I believe. The only thing I did to it bar changing that valve was to replace all the screws with torx heads so if I change those back I can get a new one and re-valve that...