Volume drop and weird hiss from OR15

[ODD1991]

Hey guys,

Ive owned my OR15 for around a month now and use it once a week at rehearsals. I usually have the volume and 3 o'clock with the gain around 11 o'clock. I run it into a 2 X 12 running a Alnico Blue and G12. Everything has been fine and the thing is a little monster, until tonight that is...

After around 90 minutes i noticed the volume drop quite significantly and then a weird hissing sound with no guitar plugged in. I switch to 7 watt and had the same issue, this went on on for two minutes or so. I left it for a few minutes and then everything carried on just fine.

Has anyone else had a similar thing happen to them?

[PBA]

It is most likely a valve (tube) problem. You may still be in warranty for valves so do check.
If not, and for the future - Get a set of valves. If you can, get the full compliment. If you can't, you should get a matched pair of EL84 power valves and a 12AX7 preamp valve. The effects loop uses (I think) a 12AY7 so that may be useful too. Once you have your replacement valves, try them out to make sure they work, then keep them somewhere safe. You need to keep notes to make sure you put the original valves back in the sockets they came from.

Power valves normally last a year or two. Preamp valves can last a lot longer. However, they can also fail randomly. The procedure for suspected valve failure is to replace the valves one and a time and see if the problem is cured. If not, the original valve goes back and you move to the next. Power valves should however be replaced as a pair and it should be a matched pair too.

In my experience, a valve failure is rarely a clear cut failure and apparently intermittent faults seem to be common. Obviously those are hardest to fix. In your case, I'd guess it's the power valves.

[ODD1991]

Thats brilliant information thank you very much. Yes I seen that the warranty covers 90 days for tubes so may try contacting Orange.

I will indeed get a full spare set of tubes as you mentioned just in case of emergencies. Such a shame as the love the amp so will get exact replacements unless anyone can suggest 'better' tubes to use in these amps.

Is this quite common with these amps?

[Jondog]

If it's a tube issue, it's just kind of the nature of tube amps. They say tubes don't last like they used to, manufacturing specs aren't as good, unless you pay heaps.

[ODD1991]

That is what I kind of thought. Cant beat a tube though, tradeoff is well worth it haha

[PBA]

...Such a shame as the love the amp so will get exact replacements unless anyone can suggest 'better' tubes to use in these amps.

Is this quite common with these amps?

It depends on which valves Orange were using at the time of manufacture, but they are likely to be JJ valves throughout. They are reasonable quality. Differences between manufacturers tend to be subtle in terms of tone but may be more significant in terms of life. Most folk would expect Chinese made valves to be less reliable than Russian ones.

ALL Valves should be considered as perishable and there is a degree of luck in how long any valve might last. You can (and should) help by treating the amp with some respect: allow it to cool down before moving it, avoid rough handling and exposure to extremes of temperature. How much difference it makes is anyone's guess but at least you'll feel happy it wasn't your fault when valve fails!

Generally consider replacing power valves every year or two. A power valve failure can cause fuses to blow but can also cause more significant damage to expensive parts such as output transformers. Preventative maintenance is therefore a good thing.

For the OR15, you can replace the power valves yourself provided you use a matched pair as it is Cathode Biased. Many other amps are fixed bias and for those you need an amp tech to re-bias after a power valve swap. All preamp valves can be replaced without re-biasing.

[ODD1991]

Yeah I think mine has JJs from standard. The amp has now been sent to Orange through GAK as it was still within the 90 days valve warranty. I would have replaced them myself but would have voided the warranty I would imagine.

Thanks for the tips, I always try my best to look after my equipment. and dont think it have had any bashes etc. Is there any other manufactures of valves out there that classed as superior to the JJs?

Just a waiting game now to get the amp back to me. Two to three weeks apparently

[PBA]

You'd be best doing some internet searching of your own - if only to see that everyone has an "opinion"! This is mine:

The best tone and reliability comes from NOS but at a significant cost. So much cost that I'm happy to accept an inferior tone!

There are no valves being made in Europe or USA.

Russian / Soviet valves are considered to be of better quality than Chinese ones but the Chinese are apparently getting better.

JJ makes valves in Slovakia using old Tesla valve making equipment. They have a website which isn't massively helpful but seem to sell valves only under the JJ name.

Winged C are made in the Svetlana factory in Russia. I've never tried them but they are meant to be good quality.

New sensor owns or runs the Reflektor (Xpo-pul) factory in Russia. They make valves under many brand names - Sovtek, Electro-Harmonix, Tung-Sol, Mullard - and probably more. They seem to be very reluctant to say what difference there is between the makes. I suspect very little... There are both devotees and haters of their products.

Chinese valves might be made in multiple factories but the only one I know of is Shuguang. A lot of their production seems to go to "Brand Name" vendors.

There are then various companies which buy valves in bulk from all of the above and sort them using their own criteria to sell on. Tube Amp Doctor (TAD), Ruby, Harma (Watford Valves) all seem to do this.

I've bought valves from many places and I've not had any real problems with any of them. Hotrox and Watford Valves appear quite large. The Watford Valves website is worth a look, but don't believe all you read. They are unquestionably hearing differences beyond the average human ear and quite possibly beyond ANY human ear!

A word of caution: The world of valves can be absorbing and astonishingly expensive. Unless you're very sure you can get what you hear in your head, try to accept what you hear from your amp...