• What if it’s not broken but just sounds crap?
• Can I get more distortion/crunch?
• Er, mate, what it is, I like bought this amp on Ebay and, er...?
• Any other recommendations for secondhand amps?
• Do you fix solid state amps?
• Can you modify my amp for harp so it sounds good and doesn't feed back? Or build me a harp amp?
• Can you make the crunch creamier? Or give it more top-end bite? Or tighten the bass? Or...
• Can you transform my amp into a custom high-gain Stevie Special?
• Do you buy/sell amps?
• Can you make my Fender 112 sound like a Marshall?
• My silverface Champ is a bit boring...
  
• Hello Steve.
• My Fender Hot Rod Deluxe / Deville is an uncouth little bastard.
• Do you do amp valuations?
• Are some components better than others?
• Can I damage my amp if I don't match the output impedance with the speaker impedance?
• Can I come round and watch you fix it?
• Can you hear that funny noise?
• Do you accept credit cards?
• Blimey, that’s expensive!
• Will you fit firecracker Chinese valves if I ask you...
• Do you guarantee your work?
• Aren’t old valves better?
• Which valves sound best? Which ones should I buy? Whose reviews should I trust?
• Do you supply valves?
• Do I need matched pairs of power valves?
• Yes but I'm a sucker, ok? Can you match valves?
• I bought new EL84s for my Laney VC30 but when I plugged them in they went pop. Wassup?
• Is biasing necessary?
• What are the best speakers? Are old speakers better?

What if it’s not broken but just sounds crap?

Glad to help.

Components drift in value on old amps – sometimes this makes them sound nicer, sometimes not. Old AC30s can lose all their bottom end this way – nothing broken but horrible nasal tone with no warmth.

This can be put right, and it doesn’t always mean replacing everything in sight at huge cost. It can however often mean it’s best to do a ‘cap job’ – replacing all the electrolytic capacitors in the amp – as these are the components most likely to drift and affect tone, and if one’s gone the others will soon follow.

Can I get more distortion/crunch?

Oh yes.

I can’t turn your AC15 into a Mesa without a total rebuild, but you can generally find a bit more gain than manufacturers build in quite readily.

The limiting factor in going for more gain and crunch is usually oscillation (a kind of internal feedback which high-gain circuits are prone to - symptoms include motorboat chugging, crackling sounds following notes, momentary volume dropout after you hit a big chord as well as various squeals and howls). Manufacturers build in a safety factor to avoid such problems – which we can nibble into a bit, or maybe a lot, depends...

Er, mate, what it is, I like bought this amp on Ebay and, er...?

...and the wife said what was actually rather a hurtful thing when you unwrapped the parcel, about it matching all the other bits of old crap that don't work that you've been filling the house with. The 'investment' argument doesn't seem to wash with her, and actually, it really doesn't work, does it, and that's going to be a little bit hard to explain.

But that's ok! I can fix it! ...Probably!

Really, buying a pre-printed circuit valve amp that's bust isn't really all that stupid (though some of the prices are). Worst case scenario - one or another of the transformers burned up, and it took some stuff with it, including whatever shorted out and burned it up in the first place. Then someone put it in a skip, then someone else took it out and put it in his shed in a sack with a load of other stuff he got out of skips (he wasn't married, obviously). Twenty years go by, time takes its toll, and the executor of his will finds it in the shed and puts it on Ebay with all his other bits and pieces, and is amazed to find it's worth only slightly less than a house. (From what I've seen this is a very typical Ebay amp sale scenario.) But it's still not a tragedy if your bidding finger ran away with you a bit. Even if absolutely everything I've just mentioned has happened to it, it might cost you, say, 300 quid or so for me to fix it - a lot less to raise your average dead amp up from the dead. Now then, to buy a new amp that good's going to cost you a grand, and a fixed-up secondhand one probably not much less... so, within limits, and after doing your sums, go for it. If you're transfixed by something bust on the 'bay, drop me an email and I'll tell you what I can about it. Good old Brit valve amps to splash out on even if they're bust include Burman (any Burman), White, some early Carlsbros especially the old 50 Top and 100 Top, and Roost, as well as the more well-known and thus expensive types.

Any other recommendations for secondhand amps?

Funny you should ask, because I do indeed. The best secondhand bargain I know is the Rivera-period (80s-ish) Fender Concert - the one in Blackface trim usually labelled 'Concert II'. This has a beautiful Fender clean sound and, footswitcheably, an excellent smooth 'American-style' overdrive. They're point-to-point circuit board wired – possibly the last ever Fender amp to be built this way - and include good things like a valve effects loop, and come in combo and in head form. Cool cool amps, so much better than a Hot Rod they're in a different universe, and cheaper too. And they'll last forever. Quite a few of them around in UK 240v versions.

The 80s Super Champ is also wonderful little amp from Paul Rivera's golden period, but then you knew that.

And if you want a high gain amp and only a high gain amp then shell out for an old Soldano. Glorious racket, sustain forever, no clean sound whatsoever.

And if you want something recent and you'd like a really lovely clean sound and also a nice crunchy overdrive then I think the best sounds come from the VHT Pittbull. Silly name makes it sound like it'll chew your head off but actually it's a nice civilised very versatile amp.

I've been hesitating about putting up this next one. Maybe I should just keep schtum, take out a second mortgage and buy every one that comes up. But because it's you I'll tell you. You know how much people will pay for a JCM800? Well, just before they made them, in the late 70s, Marshall were putting out the last of the JMP master volume amps. Lovely beasts, absolute classic Marshall rock amps that make That Sound. There are quite a few 50w two-speaker combos about. Basically they are JCM800s. It still seems to be possible to pick up a master volume JCM combo for about £400. Go and buy one, do. However, be careful not to buy an Artiste instead (fairly pointless amp from the same period that looks a bit similar). There you go, don't say I never tell you noffink.

Do you fix solid state amps?

All the time - I'll have a bash at anything.

Those big modern 300-watt-plus bass amps are generally quite fixable, which is a good job as they go pop so often. Older tranny amps are often well-built and also ready fixable. And many old or new tranny amp problems are peripheral – switches, fuses, pots – and things like that can be sorted quite economically.

A common tranny amp fault is a shorted power transistor, often caused by the great tranny amp sin, shorting out the speaker connections. Even new amps usually have replaceable power transistors. Shorted, they will cause your amp to blow fuses. Not the end of the world, although you do generally have to replace both 'sides' of the output circuit when this happens. Bit like matching valves (see below) but more crucial. Power supply faults (causing weird combinations of symptoms but usually little or no sound) and opamp failures (distortion, loss of volume, loss of sound altogether, noise) complete the list of most popular westbound routes for solid state amps. All these things can usually be fixed.

We just need to avoid situations where you end up giving me more than it would have cost to buy a new amp. Remember that you can get a gigging-volume, good quality, properly-built old tranny combo like an H/H or a Sessionette for under a ton (bargain of the century; they’re good amps) – and broken ones will sell on Ebay, amazingly enough – so please do your sums before you call me in.

Here follows a bit of a grumble, so ignore it if you like as like many grumbles it is no doubt a symptom of Weak Character. Some recent transistor amps tend to be made of specialised ICs – like computer chips – which are often either impossible to obtain or very expensive. Very recent amps have Surface Mount Technology or SMT, which makes their circuit boards both reminiscent of Solihull from 30,000 feet and also tricky to service. So if they go wrong you're meant to approach the manufacturer for a replacement board, which of course gives the faceless besuited ones the opportunity to discontinue the board and force you to buy a new amp... which is possibly good for the third world economies that manufacture the things in vast automated plants but is not good for the pocket of the struggling musician or indeed that of his ol' pal Honest Steve the amp repairman. And from this year onwards amps will have to be built with lead-free solder, and may be ruined if you try to use lead-based solder to fix them. This is so they can be recycled safely. All those '68 Marshalls in landfill sites are endangering the environment, it's got to stop. One day soon I'll have to invest in a new soldering iron for lead-free boards, not that you can do much with them anyway, for the reasons already stated. Modern valve amps are sometimes built with SMT too. You can get kit to help you fix them. But is my eyesight up to it? It's all a bit of a yawn. All of which goes to show how behind the times I will be until I get a hot air SMT repair station. Then I'll be able to fix your mobile while you're here. Why does that idea seem so hateful to me? Weak character again.

Can you modify my amp for harp so it sounds good and doesn't feed back? Or build me a harp amp?

Yes I can. I'm a blues harp player myself and I build my own gear.

The big problem with using guitar amps for harp is that they have too much gain. Harp mics put out far more juice than guitar pickups and they don't need the gain, it just makes them scream. Cut the gain and you can turn them up enough to get a nice horn-like overdrive without nasty squeals. More grind, more volume, cut through the band better. That's why old valve PA amps are good for harp - many of those old Grampians and Vortexions etc are just as good as the Mascos they love in the US. They were built to amplify exactly the same high-impedance, high-output microphones that harp players love to use. I can make a nice harp amp head out of one of them for you.

I have a standard approach to the adaptation of some modern guitar amps for harp. The Fender Blues Junior, Blues Deluxe, Blues Deville and Bassman Reissue are particular favourites. They need preamp valve swaps for less gain, and some revoicing work on the EQ components and coupling caps to restore the mids that are usually scooped out in guitar preamps (you don't want that, as harp is nearly all mids). A bit more bottom-end grunt helps too. What I generally do is a while-you-wait job, so you can try it out and we can get things just right. It usually takes 2-3 hours, which costs £60-£90 for labour, plus £10 each for any preamp valves we swap in from my stock (two is the usual maximum we'll need). 

Can you make the crunch creamier? Or give it more top-end bite? Or tighten the bass? Or...

Yes indeedy. This sort of tonal tweaking is quite easy to do and doesn’t stretch the parameters of the amp’s reliability or stability as much as going for gain does.

Can you transform my amp into a custom high-gain Stevie Special?

Well...

...not usually if it's a PCB-based amp, as the circuit is written into the board and can't easily be changed - with PCB amps I'm limited to component changes rather than circuit redesigns (these can however have quite dramatic results).

With point-to-point wired amps much more is possible, but as they tend to be worth more you might want to keep them original or at least fairly easy to return to stock. Any old components I take out of any amp will be returned to you in a little bag, so there is a degree of reinstate-ability, but if you have a '69 Marshall with all the solder seals untouched it's best to leave it that way (and sell it and buy a few crappy ones for me to hot-rod).

Do you buy/sell amps?

It’s been known. But no, not really – it’s a funny old market – everybody seems to want an immense amount of cash for their old amp – and I’m never sure who’s actually going to want to pay it. Not me, usually. I don't keep a stock, nor do I have a wonderful treasure-house of amps I bought for a fiver in the early seventies all piled up in the garage and secured with a padlock out of a christmas cracker. Sorry, burglars.

Can you make my Fender 112 sound like a Marshall?

Yeah, for about the cost of a Marshall. It’s not really sensible to try to change wholesale the character of an amp (unless it has none to start with) – it might be better to say that I could move a Fender a little towards a Marshall by pepping up the drive whilst preserving the top-end. I can make Marshalls more like Fenders too. And there's usually more gain to be found. Oh there’s no end to it.

My silverface Champ is a bit boring...

Hello Steve.

Hi there.

My Fender Hot Rod Deluxe / Deville is an uncouth little bastard. It has too much of the wrong sort of gain and directs a death beam of high frequency sound at the head of our singer, who for some reason never seems to hear a word I say. Last night he muttered something about ASBOs. Is this the kind of thing you can sort out?

What, angry deaf singers? Shouldn't think so. Oh Fender Hot Rods. They do indeed have too much raspy gain for most people's taste. Congratulations on yours (taste that is) - these little hooligans of amps have DAMAGED THE HEARING OF MANY AN INNOCENT HARP PLAYER. There are a few standard mods to tame them which I can certainly do for you to make the gain sound a bit more controllable without losing the grind. By the way have you ever noticed how loud these amps are on 2? But when you turn them up more they don't actually get that much louder? This is because the volume pot on Hot Rods is linear rather than logarithmic, as they are on less delinquent amps. Some cynical people say this is so when you plug into one in the shop you say, whoa, if it's that loud on two it must be like the four trumpets of the apocalypse on ten. And you like that, so you buy it. But then the singer starts bloody moaning, and you can't actually control the volume much, it's either on at two or off at one-and-a-half, so you say 'look it's only on two' which is a bit disingenuous isn't it? This too can be put right (the volume control not the singer), though to bring both channels into balance so you can channel-switch can be a bit complicated.

The standard Hot Rod problem is oscillation - anything from eldritch howling to motorboat phutphutting. The filter caps go. Not too hard to fix generally.

Some of the '90s Fender 'Custom' reissues also have high-gain mods as standard which can be reversed if you want something more traditionally Fender-y.

Do you offer amp valuations?

Well, that would be a moneyspinner... but why not do what I'd do and have a look on Ebay? (that's enough about Ebay - Ed.)

Are some components better than others?

Well they certainly vary.

Capacitors cause a lot of debate in this area, perhaps because the signal appears to 'pass through' them on its journey through the amp. It doesn't really, but caps can affect tone because they charge at different rates, etc. Actually decent audio caps at the kind of voltage ratings you need in a valve amp are not that widely available. I like to use Sprague Orange Drops, which I import wholesale from the USA... better than the usual little poly caps, and yes I can hear the difference and so will you, especially in high gain amps with plenty of stages for the signal to pass through.

I do think there is a slight sound difference with carbon composition resistors too (though admittedly I do feel a bit of a tosser saying this), and if I'm building an amp I use them wherever they're near the signal path and carry significant voltage (they can't make a difference if they don't, as far as I can see) - but they are hard to get and cost up to 100 times more than the quieter, utterly reliable little film types that every commercial amp uses, so I don't sweat it. Anyhow I'm probably imagining the sound difference; we're all a bit susceptible to vintage amp voodoo and I'm no different. As yet I've remained immune to paper-in-oil caps, but that's no doubt because I've managed to avoid finding out where to get them.

(See below for the old valves issue)

Can I damage my amp if I don't match the output impedance with the speaker impedance?

Certainly you can.

With transistor amps you generally have a free choice of speaker impedance so long as it's above 4 ohms. Some will go down to 2 ohms. Shorting out the speaker connections on a tranny amp is very likely to cause major damage.

With valve amps the major danger is running the amp with no speaker connected. This presents the output valves with infinite impedance, and since their current is restricted they respond by trying to supply infinite voltage. Sparks fly inside the valves and around the output transformer, and both can be damaged.

It follows from this that the real danger to valve amps is too high a speaker impedance, not, as most people think, too low. Plugging a 4 ohm output into a 16 ohm speaker is thus more dangerous (developing dangerously high voltages, sparks fly) than plugging a 16 ohm output into a 4 ohm speaker (works the valves a bit too hard).

So match up output and speaker ohms with valve amps. If you run into an emergency at a gig I wouldn't worry too much about a one-step mismatch - 4 ohm output into 8 ohm speaker, 16 into 8, etc. Two steps is to be avoided, especially 4 into 16.

Can I come round and watch you fix it?

While-you-wait is possible if we can find a convenient time.

If it’s a ‘tone consultancy’ thing then I’d actually prefer it if you could come so we can listen together to the problem and the proposed solution. Your mileage may vary, as the yanks like to say, and what I think sounds fab may be ear-torture to you.

Can you hear that funny noise?

What, kind of a hummy whistley noise? That's the Russians again, trying to fry our brains. Oh, I see, from your amp. 

I am patient and understanding about this sort of thing. I may well not be able to hear your funny noise, but I will as a first principle take your word for it and, if it seems realistic to do so, try to do something about it. On the other hand, if I say there's not much point me fiddling around it's not that I think you're imagining things, I'm just trying to save you money.

Do you accept credit cards?

Sorry, I don't – too much infrastructure hassle. Cheques... well, you understand... can't really do that. Payment in cash on collection makes sense for me, so I make that my formal 'terms of business'. 

Blimey, that’s expensive!

Valve amps aren't cheap to build, buy or service - but there’ll be no nasty surprises if I can help it – I’ll always give you a warning to avoid getting you into a money-pit situation. I believe I offer good value compared to others in terms of my hourly rate (and I do work fast), and I will be decent and sensible and not get you into uneconomical repair costs when you'd rather have given it up and bought a new amp. Don't be afraid of asking me about costs, we're all on budget these days.

Will you fit firecracker Chinese valves if I ask you...

Whatever. Reliable valves are available new, at reasonable prices.

I tend not to use Chinese valves because they had a bad reputation in the past, but I’m told some of them are now good. I’m not xenophobic; anyway glass and metal are glass and metal.

Do you guarantee your work?

I guarantee that what I’ve charged you for is what I’ve done, that I use reliable parts and that I do things properly, that the bits I've fixed won't come unfixed because I didn't fix them properly, and that I didn't unfix anything else while I was fixing it... and that if I do fail you in any of these ways I will put it right for nothing if you bring the amp back to me.

I can’t guarantee that something different won’t go wrong tomorrow – old amps are like that – but if you ask for a service (generally an hour’s work; not usually more than two) I will pick up anything that looks close to its sell-by date and let you know. Basically think of it as like the relationship you have with a good garage who look after your car.

Aren’t old valves better?

I don’t especially recommend ‘NOS’ (‘new old stock’ or ancient but unused) valves, unless you’re interested in collecting them or seeing how they sound for the fun of it.

These days the manufacturers in Eastern Europe are producing valves with most of the qualities of the old Western European manufacture, y'know, black plates, mica spacers, D-getters and all the rest of the b****cks. Well, ok, maybe there are a few really high-end things you don't get that you used to get - super-pure materials, ultra-hard vacuums - but sound for guitar is not going to be affected by that stuff, let's leave it to the hi-fi guys to worry about whether it's worth a 2000% mark-up. That's if they've any change left from the £500 they put aside for speaker cables (don't tell them about 2-core mains flex, that's our little secret). Even previously hard-to get valves aren’t so any more. 6v6s used to be a problem, for instance, but now JJ and Sovtek (badged Electro-Harmonix) both make a good one.

Btw never ever buy a stubby little 6v6-labelled effort covered with black paint inside all the way up the glass, these are possibly the worst new-manufacture valves ever sold and aren’t really 6v6s at all. I really like the new JJ 6v6. Smooth yet crunchy, like a toffee crisp. My harp amp has four of them.

Which valves sound best? Which ones should I buy? Whose reviews should I trust?

You really are getting anxious aren't you? To answer the last question first, if you type '6L6 review' into Google you'll find that there are some reviews on forums, which may be unbiased but may also be from (a) nutcases (b) people who are trying to justify having recently spent three figures on two valves. There are also some reviews by people in the trade, which won't be nutty but, being written by valve retailers, may naturally enough be affected by a wish to retail valves - especially expensive ones or ones you branded yourself. Both types of review are full of useful information, but caveat emptor and anyway because these reviews focus on the subtle little differences between brands rather than the overwhelming similarities amongst types of valve they will tend to draw lines that aren't really significantly there.

So are there any differences between brands that actually matter? Well yes. In my view there's a much bigger difference between a poor current-production valve and a good one than between a good current production and a NOS valve. Internet reviews tend to agree on the ones to avoid so they are easy to spot. There's a big mystique thing about NOS valves as well as the supply-and-demand factor - witness the big prices now being asked for winged-C Svetlana 6L6s, valves that only very recently were current-production and cheap but now are expensive (and still being produced in St Petersburg, marketed by PM Components? I'm not altogether sure; let me know if you are). Anything with a winged C on it is dearer now because of this, but the current run of Sovteks are by and large good valves, and you can't blame them for making a reissue of the Svetlanas even if it's not really the same (it is a good valve though, I've heard them).

Good cheap current-production valves I know about (and NOS valves I've experienced thanks largely to customers) include these:

EL34: The current JJ EL34s I sometimes use are good in terms of clean sound. They can be driven into distortion satisfactorily in non-MV Marshalls etc though they have quite a lot of headroom. The newer JJ E34L has even more headroom if you want it loud and clean. Both valves are available in blue glass, which has a similar effect on tone to purple pilot light jewels. The Sovtek 6CA7 (same as EL34) is cheap and well-liked - I very much like these - a bit smoother and fatter than the usual run of EL34 types... which is the reason why I now stock them and fit them as my standard EL34 type. I've heard the Mullard reissues - they don't sound like bad valves to me but I didn't try them exhaustively. There's a tendency to rubbish reissues just because of the sucker factor - but we all know they're not really Mullards don't we? And everything you buy is branded one way or another, and isn't there a strange paradoxical kind of honesty - or anyway a pleasing postmodern irony - about putting new wine in old bottles in so egregious a way? So long as they don't charge too much more for it. I have tried real NOS Mullards in a pre-MV Marshall: clean, they have a good balance of highs and lows, lacking the harsh highs of some 90s production valves, eg older Teslas. Overdriven at high volume levels they hit you in the chest with overwhelming power - but still stay quite smooth-sounding. Probably it's that overdrive sound that makes the difference for me - I haven't yet heard a modern production EL34 that isn't a little bit jagged-sounding overdriven in a Marshall. But maybe you like that.

6L6: The JJs are good all round sonically and have the 6L6 sweetness in the top end that I personally look for, but tend to cost 50% more than other types, so I'm using others. Any Russian 5881 (equivalent to 6L6) will be reliable and not sound bad, though maybe without some of that sweetness? Hard to be sure; they do sound good. BTW avoid anything labelled 6L6B (there is a current production valve you might see cheap on Ebay) for Fender and most other guitar amps as the B suffix means they can't handle big plate voltages. 350v max on these. C suffix is the one you need for high-volt guitar amps. G suffix means made of glass, as opposed to metal - incidentally I've heard one of the old metal ones and it sounded really good, but turned out to be microphonic. The Svetlana reissues currently around sound fine and are reasonably priced - but once more there is the fact that they aren't actually the same valve as the old ones (and apparently aren't available to the UK any longer). I'm not a party to the Winged-C magic - I've heard them but to be honest I couldn't differentiate them from the JJs, and I did like the sound of the reissues. Soon I'll be testing Sovtek's 6L6 WXT+ (NB - just got a shipment of these in because it seems New Sensor can't sell their Svet clones in the UK any more... more later on just how they sound but I stuck some in a Vibrolux to try them out and they sounded fine). I have played RCA blackplates in various early-60s Fenders. They sound more controlled than current-production valves, perhaps because of a good balance between frequency levels. Very sweet chimey highs, tight bass. Could I tell the difference from a JJ or a Svetlana in a blindfold test? Not sure. I'd be listening for that top end sweetness I keep going on about.  I have one coke-bottle RCA I got unused, still in its brown wartime box and padding, in a garage sale. I put it in a single-ended amp my son and I built for him to use. (That's the kind of father I am - gullible). It sounds lovely, very lively and 'real' with smooth rounded overdrive.

6V6: The JJs are great - smooth and clear and sweet with a lovely rounded almost-civilised distortion sound. They are tall though, so check there's room - and they're not that cheap. The EH 6V6 is stubbier like the old ones were, cheaper and still sounds fine. NOS American 6V6s are still quite reasonable - about £20. I heard some GEs in a customer's Super Champ, and they sounded gorgeous - that Fender sound that is full of tops but could never be painful to listen to. Pure chime. And what a bargain compared to NOS 6L6s.

EL84: The JJs are excellent and cheap, so I use them all the time. They are pleasantly chimey and overdrive quite easily if you're into turning your Vox-type amp up. I've heard the Sovteks and they are not bad valves, though I've seen a few fail (maybe this is because so many manufacturers use them). I don't know much about NOS EL84s but they get a lot of praise.

ECC83/12AX7: The JJ ECC83S sounds good, is low in microphonics because of the small plate (probably) and low in hum because of the spiral filament, and is good and cheap, so for guitar amps I don't look further, though I often see various EH Sovteks and they are good too... the Sovtek LPS valves sound very good indeed but in high-gain amps can be troublesome first stage valves because of microphonics/noise, as LPS stands for large plate structure. I do have a recurrent experience of testing older-type Sovtek 12AX7s and finding that their gain levels have sunk below the acceptable, so if you have an amp with old Sovtek preamp valves you might spice it up interestingly with a new set. Old used Mullards, Brimars etc usually in my experience have lost their egde gain-wise too, I'm sorry to tell you. The older Chinese valves have a distinctive shiny metal structure which partly wraps around the greyish plates; a lot of companies relabelled these in the 80s and 90s. They are usually in a poor state in the amps I see, and so I doubt their longevity.

ECC81/12AT7: There are some very nice Phillips/Jan valves around at goodish prices (eg ten quid each from me) - they sound very fat and solid to me as first stage valves in old Fenders (if you're not after a lot of gain) or as splitters - I do like to retain ECC81/12AT7 types where they are specified as splitters because their excellent current gain makes for a nice fat meaty sound - very like the cathode follower circuits driving tone stacks in my favourite preamps. The JJ ECC81 is fine, and I don't recall any negatives about the Sovtek/EH 12AT7s either.

One little note about preamp valves. The ECC82 is not midway in gain between an 81 and an 83 as you can read in some places on the dear old unreliable web, but is actually a very low gain valve, way less than an 81, with little or no usefulness in guitar amps other than as a trem modulator in AC30s etc (can be handy for harp though).

Do you supply valves?

I keep small stocks of the common types - my idea of the best current-production lines available. These are:  EH 6CA7s for your EL34 applications; EH 6L6WXT+ (just got a shipment of these, tried them and they sound good - more on this later), and JJ EL84s and ECC83S-es. Generally I add £10 to the bill for a preamp valve, £15 for a power valve and £25 for a pair of EL84s. I will sell them to you, matched if you like, at these prices if you want. If you'd rather plug your own in that's fine. You can give valves to me to fit/bias if you like. If you have some old valves hanging around I can test and match them up for you.

Do I need matched pairs of power valves?

No you don't, is the simple answer, unless your driver circuits and (above all) output transformer are balanced too. Which they never are. Or unless you want the absolute maximum output from your amp, in which case you need to have the pair balanced up IN THE AMP. Unbalanced valves might introduce a bit of even-order distortion - yes, they can sound better!

Exceptions: if you have a single bias adjustment for a push-pull (output valves in pairs) amp then it is worth checking that the currents in the valve(s) on each side are not so far apart as to cause hum problems or huge inefficiency. Too far out of balance and you start to lose the handy humbucking funtion of the push-pull pair. But even then I often find that swapping the valves around inside the amp levels things out, as guitar amp output trannies (which are cheap and lo-fi) can easily offer 30% differences in impedance between the sides... which of course is why there's little point in balanced pairs in guitar amps! SVTs are another exception, but then they're an exception to everything - with six power valves in push-pull the differences can really add up, and if you have a later one with the little red and green bias lights it will be hard to set up without balanced sets of valves.

As you'll gather, I do try to balance valves IN THE AMP while biasing it up - and if you give me any extra valves you have hanging around I'll try to balance up the currents for maximum efficiency, if that's what you want.

I wish I could come up with an idea like balanced pairs of valves, I'd make a fortune. (Too late, it's been done.)

Silverface Fenders often have a hum balance control which allows you to balance the bias voltage between the two push-pull 'sides'. Works a treat, you can stick in any old 6L6-es and dial the hum right out. Set the overall bias with the resistor that goes to earth, if you need to. Good job they didn't persist with that idea, or where would the valve-matching suppliers be?

Yes. I have a good tester and can match up pairs for you from a batch, if you're the sort of person who can afford a batch of new valves. If you have some old valves you're not sure about, leave them with me when you leave your amp and I'll check them out. I usually test valves in any amp that comes in and I will try to get some kind of balance going in your amp.

John from Champ Electronics in Nottingham (see Links) reminded me of this one. The sockets in the VC30 are wired up to accept only one type of EL84. They use a pin that has no connection on some valves as part of the circuit - however other EL84s do have a connection there - and pop they go when you plug them in. Not too hard to rewire the sockets if you have this problem. The advice is to get this job done before plugging in any new power valves except those Laney supply.

While we're on the subject, John pointed out another issue on a VC30 he had in. He'd sorted the wiring thing, but still found that one of the power valves glowed red on the plates however many times he checked the bias. Then he noticed it was very close to the speaker magnet. The magnetic field was helping the current flow, overheating the valve. Well spotted John. Tricky little amps, VC30s.

Is biasing necessary?

Aha, the issue of issues.

It’s wise to have it done when you change power valves, yes, though not always an urgent necessity - depends on the situation.

Biasing is done to adjust the current that flows through the valve. Bias is a negative voltage that acts as a brake on the main current carrying the amplified signal through the valve (in a manner of speaking).

The more bias voltage you apply, the less current flows through the valve. More current gives more wattage, but there’s only so much the plates will take, and that’s where the danger is. If the metal plates you can (usually) see inside the glass start to develop a red patch – that’s too much current and the valve is being destroyed (so turn it off quick and get it rebiased).

Apart from this safety/valve survival issue, bias becomes a matter of taste. High current gives you power/volume, clarity, good chimey top end. Less current gives you earlier breakup, with less volume, less clarity and top end. Usually I bias for power and clarity – if you want me to go for less volume and a browner, distorted sound, let me know – some amps suit this approach better than others, but generally low currents, like low voltages, in power valves don’t really deliver the distortion sound you’re probably looking for.

Some amps have a self-biasing arrangement (which is the secret of those new amps you can get where you can swap output valves) – but even they are worth checking out when you put in a new valve. It’s not going to take me long to adjust your bias in most cases.

One more thing: For some reason, Peavey valve amps have a tendency to leave the factory biased very 'cold' - that is, set up so that the current through the power valves is very low indeed. This is particularly true of the 5150s, but I've seen it on many and various Peaveys, the exception being the EL84 amps which, like most EL84 amps including the AC30, are biased for incendiary levels of heat. But Peavey 6L6 amps and others in the 50-100 watt range are often  biased way cold. I'm not sure why they do this - either so that the valves last longer, or in pursuit of distortion, but if you feel that your Peavey sounds a bit thin and bluebottley this may be the reason. Unfortunately most Peaveys don't have adjustable bias and do have PCBs, so it's not just a matter of twiddling with a trimmer, but it can be worth setting the bias properly, or installing an adjustable bias system (not very hard to do).

One more other thing... adjustable bias and fixed bias are not opposites. In fact most amps with adjustable bias are fixed bias. The common alternative to fixed bias is cathode bias, which isn't so easily adjustable. OK? Glad that's clear.

What are the best speakers? Are old speakers better?

I’m a bit heterodox on this.

Unless you specify otherwise, I’ll replace clapped out speakers with a decent modern ceramic, though with classic amps you should always keep the old speakers of course, as they can generally be reconed and are a crucial part of the amp’s value. Good new ceramics are cheap (really cheap – less than £30 for a 12 inch), sound good and loud, and they let the amp speak.

There is an immense confusion of voodoo out there about speakers, as I’m sure you’ve noticed – all the disagreements are a sure sign that there’s really not much difference anyway.

Old speakers tend to sound less forward, with looser bass; the top end goes as the cone gets flabby. People like alnicos but I can’t really hear the difference separately from all the other differences between speakers.

‘Earlier breakup’ – I’m not sure I want to push my speakers that hard, can’t be good for them.

For me the best thing about valve amps is what they add to the top end – a lovely mix of harmonics that makes a clean guitar really chime and sing, and makes distortion musical. I like a speaker that doesn’t get in the way of that.

But of course I’ll fit anything you want fitted, and give you my view on what you’ve already got and how you might make it more like what you want it to be.