Recommend me some tubes/valves

Ravelleman

So as you may know, I recently bought a second hand ENGL Thunder 50 Combo (the one without reverb) on ebay.de and was complaining about the buzzing coming from it. Anyway, long story short, it's still buzzing like crazy so I think I'm finally going to bite the bullet and replace the tubes.

This is my first tube amp so I'm finding the whole prospect a little bit daunting. I've no idea where to start looking for new tubes or what brand I should buy. Can anyone give me a place to start looking or even recommend some tubes? I'd like to spend about E200 in total (on tubes, shipping and any other eventualities) but still, I don't want to do a half assed job on it so I can spend more than that if necessary.

In the manual it says it uses:
V1 (input-tube): ECC-83 /12AX7, FQ Grade;
V2, V3: ECC-83 / 12AX7 selected;
V4: ECC-83 / 12AX7 standard
V7, V8: 5881 (6L6GC) matched set.

Also, can someone explain rebiasing thing to me? Is that necessary?

Thanks, and sorry about my shameful ingorance. :v:

feylya

www.eurotubes.com

Get 4 12ax7's and 2 6l6's (matched) or just email eurotubes and ask them to recommend. I do believe Karl Hungus and dabhoys are very impressed with their tubes.

bombidol

I recently bought a Peavey 6505+ and its coming with tubes etc but i might replace them with Mesa tubes which are the business i hear. Anyone know ?

Eoin Madsen

I don't think you can change the bias in an Engl without modding it. You're supposed to buy valves that are matched specifically for it, or somesuch. I'm entirely sure, I haven't had the opportunity to study one. It should explain it in the user manual anyway.

http://www.watfordvalves.com are a good valve shop as well.


The only people I've heard of that think Mesa tubes are the business are Mesa. They're rebrands anyway.

Ravelleman

I decided to go with some JJs from Eurotubes since they have good feedback all around. They arrived yesterday. What do I have to do to install them? I presume it's just a matter of pulling the old ones out and putting the new ones in...:o

HusseinSarhan

www.kcanostubes.com Just read your last post there but that's a good site anyway. installing them is easy. Unplug the amp and replace them like lightbulbs.

Karl Hungus

Ravelleman wrote:

I decided to go with some JJs from Eurotubes since they have good feedback all around. They arrived yesterday. What do I have to do to install them? I presume it's just a matter of pulling the old ones out and putting the new ones in...:o

Pretty much, but use a clean, lint free cloth to handle them.

HusseinSarhan

Karl Hungus wrote:

Pretty much, but use a clean, lint free cloth to handle them.

If you are arsed. For instance, if you get nice JAN philips ones you can be pretty sure they'll manage ok without a cloth, they were designed for military use afterall! Most are pretty much of the same stability and are not nearly as fragile as most believe. However, do be careful still. I suppose if you mean using a cloth to avoid getting burns then that's a good idea. I'd prefer to wait for them to cool down for a minunte and remove them without the cloth using clean/dry hands. You'd get a better grip on them.

Ravelleman

Ok so... here we go



The tube on the right is the phase inverter - right?

Ancient1

If i were you i'd look into draining the filter caps first.

feylya

To an Amp Tech with you tbh.

Ravelleman

Ancient1 wrote:

If i were you i'd look into draining the filter caps first.

*head explodes*

Ancient1

Don't quote me on anything :v:

I suppose that would depend if you're biasing your amp or not (see Eoin's comment above). I would strongly suggest that you take an hour to go through this site.

Of course, I'm fully aware that all the modifications and repairs are specifically for the HRDx and not for your amp, but it will give you a really good idea of how a valve amp actually works and everything you need to know about tube maintenance, biasing, draining filter caps etc. It really does offer a wealth of information and i learned a lot from it.

In case you do have to drain the caps, i suggest you take your amp and the tubes down to Jimmy in SoundGear. Personally i don't think i'd be brave enough to do it myself, but then again i don't know much about poking inside amps. Eoin's your man for that.

Hopefully you'll find something useful on the site anyways.

Ravelleman

Thanks for the link. That's exactly what I need. I'm not exactly sure what I'm doing here. My main aim is to stop the buzzing in the amp. Everything else is secondary to that really. Biasing and all that seems like a good idea but I suspect that's a bit more advanced than my simple aim. I want the experience to be as painless as possible.

Ancient1

I really don't know if your amp needs biasing. In my very limited knowledge, most amps could do with biasing for the simple reason that biasing sets out the working conditions for your tubes.

The buzzing in your amp may not be tube related either, it could be a capacitor or some such yoke which got detached from the PCB. If you change the tubes and the buzzing persists, then you need a tech to look at it. Most of these problems are relatively easy to figure out and fix, but unfortunately not something mortals like us can do - unless of course you know what you're doing.

Ravelleman

Maybe I'll just take the lot down to Soundgear then and see if they can sort it out for me - buzzing, tubes and all. I doubt I'll ever find a solution myself. Any ideas how much it might be?

Ancient1

When it comes to service and people who actually know what they're doing, no one comes close to the guys in Sound Gear. I'll dig up Jimmy's number tomorrow and give you the details.
I have no clue how much it would cost, but i doubt he'll give you a quote for more than 40-50 yoyos tops.

Ravelleman

Thanks a million.

Eoin Madsen

You don't need to drain the caps unless you're opening up the inside of the amp. Valve swapping itself doesn't require this, though biasing would. Read the amps user manual (or google it) and find out if it's fixed bias or if it can be adjusted. If it's the former, as I suspect, then you need to get valves properly rated for the amp. Or just try your luck with whatever you have I guess.

HusseinSarhan wrote:

If you are arsed. For instance, if you get nice JAN philips ones you can be pretty sure they'll manage ok without a cloth, they were designed for military use afterall! Most are pretty much of the same stability and are not nearly as fragile as most believe. However, do be careful still. I suppose if you mean using a cloth to avoid getting burns then that's a good idea. I'd prefer to wait for them to cool down for a minunte and remove them without the cloth using clean/dry hands. You'd get a better grip on them.

The purpose of using a cloth is to prevent oils from your skin from getting on the glass, shortening the life of the valve.

Ancient1

Ravelleman, here you go:

Sound Gear
24 South Richmond Street, D2
Tel/Fax 01-475 5794
Tel: 01- 475 7226
Email: soundger(at)iol.free
(that's "ger" not "gear" on the email for some reason)

Rory O'Connor is the chief, but i think you should talk to Jimmy.

Good luck.

HusseinSarhan

Eoin Madsen wrote:

You don't need to drain the caps unless you're opening up the inside of the amp. Valve swapping itself doesn't require this, though biasing would. Read the amps user manual (or google it) and find out if it's fixed bias or if it can be adjusted. If it's the former, as I suspect, then you need to get valves properly rated for the amp. Or just try your luck with whatever you have I guess.



The purpose of using a cloth is to prevent oils from your skin from getting on the glass, shortening the life of the valve.

I did say clean dry hands. Which means washingthem beforehand. I seriously don't think it shortens the life of them that way at all. Certainly not measurably.

The HRDX cannot be biased in its stock form. Its fixed cathode bias. You can mod it but that'sa different story. Draining the caps would make the job that bit safer but to be honest its not necessary for this. A quick way to semi drain the amp is to play it as normal and then turn it off using the power (not standby) switch and conjtinue to play until the soun fades. Turn up the amp volume until you can't here yur strumming any more. There will stil lbe some latent current in the amp when you plug it out, but not enough to kill you, just give you a shock.

Anyway, you don't need to worry about shocks if you ggo about this righ. screw the chassis off the cabinet and remove the chassis tray. Those look as if hey could be PCB mounted valves (what a stupid design, cheaper yes but really silly in terms of maintainance and thread damage) sobe careful when taking them on and off the pins as you don't want to damage the circuit.

They are a user servicable part so you should have no problems doing this. If you are not confident bring it to a tech, but its a simple job.

As for the buzz well it could be a lot of things. Best thing to do is eliminate the obvious. Try it with a different guitar and different lead. it could be a grounding issue so try it in a different plug socket in a different room. what is the buzzing like. Any pops or hissing at all? Does it change according to what the controls are set like on the amp. It sounds like you may have to take it in, but don't let them tell you that they'll have to do a "valve change" like it's some big deal. also, remember you don't set the bias on this amp so they can't be charging you for that.

Good luck


EDIT... just looking at that you probably don't have to remove the tray at all. Just those valve covers.

Ancient1

HusseinSarhan wrote:

The HRDX cannot be biased in its stock form.

The HRDx does have an adjustable bias pot, but Ravelleman has an Engl - and we're not sure if that one can or cannot be biased.

HusseinSarhan

Ancient1 wrote:

The HRDx does have an adjustable bias pot, but Ravelleman has an Engl - and we're not sure if that one can or cannot be biased.

Is that not a hum balance pot? I think it's inernal for the bias if there is one, so it's probably not a USP. I don't know, I reckon the ENGL is fixed too.

Ancient1

Yeah, the pot is internal so that's a major pain.

Ravelleman

HusseinSarhan wrote:

As for the buzz well it could be a lot of things. Best thing to do is eliminate the obvious. Try it with a different guitar and different lead. it could be a grounding issue so try it in a different plug socket in a different room. what is the buzzing like. Any pops or hissing at all? Does it change according to what the controls are set like on the amp. It sounds like you may have to take it in, but don't let them tell you that they'll have to do a "valve change" like it's some big deal. also, remember you don't set the bias on this amp so they can't be charging you for that.

The buzzing is a constant sound in the background. It almost sound like the buzzing of a bee. Occasionally I notice a very slight fluctuation in the sound. I can't describe it. There's no fizzing or popping as far as I remember. A few days ago I noticed that the amp picked up a radio signal. This has only happened once. The buzzing is always in the background as I play.

I'm using a Fernandes Ravelle with two Duncan humbuckers. No single coils at all. The buzzing lessens very slightly if I touch a metal part of the guitar.

I've tried the amp with a few different guitars - all with similar results. I've tried four or five different leads and there has always been buzzing, though the sound of the buzzing does change slightly with each lead.

The sound of the buzzing becomes more intense as I raise the gain control - especially anywhere past 3 on the gain control. The bass control has no effect on the sound. The middle control has an effect - if it's turned down the buzzing becomes less pronounced. Of all the EQ controls, the treble control has the most obvious effect on the buzzing. It's similar to the middle control but a lot more pronounced when turned all the way up.

I moved the amp around the house, using different plugs and extension cables, and two different power cables - one rewired with an Irish plug and another using an adaptor. In one room the buzzing was high and fast. In another it was slightly lower and slower. The different cables had no real effect.

Regarding tube: I have a replacement set of JJs here. Two matched 6L6GC, 3 high gain ECC83S and 1 balanced ECC83S for the phase inverter. All the currently installed tubes have a healthy looking orange glow from the filaments. However, one of the power tubes is slightly bent out of place as can be seen in the pic. Not sure if that could be a problem.



I can't find anything in the manual about the bias.

At this stage I'm sure I'm gonna take it to a tech. I've already bought the tubes so it shouldn't be too expensive and I seriously doubt that I can fix it myself.

Ancient1

Ravelleman, I don't know how I didn't read into this before, but I think I geddit the way you describe it now.
In my opinion - it's the nature of the beast, much like single coils!!

I'm sure many will disagree, but in my experience, I have yet to see a tube amp that is super quiet. I don't know if at this point one should distinguish between heads and combos, but I think that all tube amps "buzz". I could be wrong of course.

Tube amps are by their very nature much more "volatile", for wont of a better word, and much more "inefficient" than transistor amps - it's just how it is. I've had tube amps with varying degrees of buzzing and I think it's normal to have a bit of buzz in the background as long as it's not really annoying.
It doesn't bother me personally - it's very audible when I play at home, but it's almost never audible in a rehearsal situation.

What do you guys think?

Edit: "The sound of the buzzing becomes more intense as I raise the gain control - especially anywhere past 3 on the gain control. " I consider that normal, it happens on my HRDx too.

HusseinSarhan

It should not buzz that much. Reseat that 6l6GC, though that is not the problem . I don't think you should worry about the biasing. It's really more of a factory option not user serivcable really. Anyway, try swapping the V1 (1st gain stage pream slot) 12AX7 (ECC83) for 12AT7, you'll notice a small decrease in the dirt you can get out of the preamp but your buzzing may lessen. Is it near any CRT monitors, flurescent lighting?

Eoin Madsen

It's normal enough for the bias to be on the inside. Biasing requires inside access for measurements anyway so it makes no difference.

Back to the valve cloth thing... washing your hands doesn't remove all of the oils on your skin. I doubt anyone has actually done a control experiment to see if the difference is noticable under marginal circumstances, and I'm sure you get away with it, but that's not really the point. Accumulated oils can cause a valve to overheat, so it's just not good practice. Doing it yourself = fine. Recommending that everyone err on the side of having the same slack attitude = pointless.

Okay, the fact that the input gain control increases the volume of the buzz means that the noise is bring introduced in or before the first gain stage. Meaning the problem is between the guitar pickups and the first valve. One question to make sure - does it still buzz with the gain down (but the master volume up)?

Ravelleman

It's not near any CRT monitors or flurescent lighting.

With the gain down and volume up there's no buzzing. There is a noise though - it's like a constant 'sh' sound.

Eoin Madsen

The slight hissing is normal, any amp with a respectable high frequency response will hiss a little. The fact that the buzzing stops when you lower the gain is a fairly sure sign that it's coming from the early input stage, or your guitar. Standing too close to the speakers will cause magnetic interference in the guitar pickups, which does manifest as buzzing. So make sure you're not aggravating the problem while you're trying to troubleshoot it.

Another thing to check would be whether it worsens when you're not touching any of the metal on the guitar.

Ravelleman

The sound of the buzzing does lessen when touching metal on the guitar.

HusseinSarhan

The only reason I wouldn't use a cloth is that, especially when talking about valves that have not been removed in sometime, you can get a better grip with you fingers. The cloth causes you to put more pressure on the glass to get a decent grip on them, which is considerably more dodgy I think. I think cotton gloves would probably be the best option you you were doing it a lot. No oils, more grip.

To be honest, you are best giving them a wipe after installing them, a gentle one. That way you remove the oils (espeically if you use a microfibre cloth). Makes much more sense I think. You have to be touching the valves an awful lot, or be a real oily person for it to have a significant difference, if you don't think to wipe them off. Although, you are right, in the long run you are probably better off removing these oils.

Eoin Madsen

Oil doesn't entirely wipe from most surfaces, you have to use an emulsifier. That's one of the physical properties of an oil. Any kind of film on the glass increases the amount of heat retained by the glass - slowing the rate at which heat is convected from the valve, and increasing the amount of heat radiated back into the valve. The same thing happens with light bulbs, apparently. I don't know how much research has been done into establishing the exact practical implications of this fact in all likely scenarios. I will concede that I have not yet come across a published paper on the subject.

Yeah, some kind of gloves would be easier than a cloth.

Eoin Madsen

Ravelleman wrote:

The sound of the buzzing does lessen when touching metal on the guitar.

Significantly? Something is contaminating your ground, early in the chain. I'm honestly not sure what could be causing it, though it seems to be a particularly common problem around these parts.

I'll go research this one I think. If I come across anything useful I'll post it up.

Sid71

Or you could try Martin @ 01 8316168

Ancient1

Sid71 wrote:

Or you could try Martin @ 01 8316168

Who he?