You are here

Valve preamps, powers amps and a possible rabbit hole...

For all things relating to guitars, basses, amps, pedals & accessories.

Valve preamps, powers amps and a possible rabbit hole...

Postby Hewesy » Sat Jan 26, 2019 3:59 pm

As per the title I have a feeling I might be heading down a rabbit hole and I really need the collective wisdom of the forum to put a light at one end of the tunnel!

I have a Laney VC30 (mk1, slightly modded with a Celestion G12H Greenback instead of the original HH) which runs ECC83 preamp valves and EL84 power amp valves.

Now I love the amp, it does that "chime" thing very well and the clean sound is great but it just doesn't offer the warmer, crunchier drive that I'd like, which seems to be a similar characteristic to most "classic" amp circuits based on EL84 (such as the AC30 it's modelled after). I've gone through stacks of drive pedals too, none of which really fit the bill - probably the age old pedal issue of trying to add something which just isn't there. For reference I don't want anything really heavy, more the classic drive/crunch, kinda Angus Young, Paul Weller, more the JTM/Bluesbreaker combo type tone.

Originally I though of adding a Blackstar 10w anniversary or smaller HT5 combo, maybe the 18w Marshall combo, which seems to fit the gap, but with Victory bringing out their V4 valve pedal based preamps I immediately thought this was the answer to my particular problem. Now I could keep the Laney's clean tone and use the V4 (probably the Sheriff model) to add the drive. No need for that 2nd amp/powersoak/long conversation with the neighbours after all.

But, and this is where the rabbit hole appears, am I on a hiding to nothing as the power amp is still EL84 based? Or is it worth a shot as a number of the Blackstars, as example, are EL84 based?

I appreciate the short answer is try it and see but none of my local dealers stock, or appear to want to stock, Victory kit so I'm back to a mail order/return process.

Collective thoughts or head slaps welcome...!

Hewesy
Hewesy
Frequent Poster
Posts: 752
Joined: Tue Oct 19, 2004 12:00 am

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Hewesy » Sat Jan 26, 2019 4:41 pm

I may have answered my own question here - the Sheriff 22 is an EL84 amp, I've only looked at the 44 before which is EL34.

Hmm...

Hewesy
Hewesy
Frequent Poster
Posts: 752
Joined: Tue Oct 19, 2004 12:00 am

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Wonks » Sat Jan 26, 2019 5:14 pm

If you aren't actually driving the output valves hard, then I don't think the valve type will matter too much. But I fear it really is a matter of keep trying and seeing what sounds good.

Have you tried a simple treble booster - the original way to get an AC30 to sing?

What version of the G12H do you have, the 55 or 75? It's hard to tell accurately from the sound clips on the Celestion web site as they are all at different levels, but the 75Hz resonant peak version seems to have a bit more edge and bite to it in the distorted sound clips.
User avatar
Wonks
Jedi Poster
Posts: 8954
Joined: Thu May 29, 2003 12:00 am
Location: Reading, UK
Correcting mistakes on the internet since 1853

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Hewesy » Sat Jan 26, 2019 7:10 pm

Thanks Wonks, I'm using an attenuator but not cranking too much at all really - bedroom level.

My bad, my memory is worse than I thought it's the G12M 25w. For some reason I though the G12H was 25w and there was then high powered versions. Which now I think about it is probably what the H denotes... :headbang:

I haven't tried a treble booster, I suppose I've always had a mental block with Dr May' s use of one but could be worth a shot first. Any recommendations?

Cheers mate,

Hewesy
Hewesy
Frequent Poster
Posts: 752
Joined: Tue Oct 19, 2004 12:00 am

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby ef37a » Sat Jan 26, 2019 7:17 pm

The only Blackstars using EL84s are the "classic" Artisan 15 and 30, rather pricey.

The new single ended amps use EL34, 6L6 or KT88. The HT-5 is a 12BH7 double triode and the HT-20 two EL34s in a near cathode biased, near "class A" mode and they have just released re vamped versions. There are YTs of the last two online.

But, I have a suggestion that could save you quite a few quid? Check your dealer for an HT-Dual pedal. That has 3 "channels" TMB EQ and the ISF control which, in conjuction with the mid control give you a vast range of tones and a very wide range of distortions.

There is also an emulated output that can feed an AI or even straight into a PC soundcard jack.

Sorry about the spammy nature of my reply. I am not on a bung..Honest!

Dave.
ef37a
Jedi Poster
Posts: 10528
Joined: Mon May 29, 2006 12:00 am
Location: northampton uk

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Wonks » Sat Jan 26, 2019 7:31 pm

I'm using a TC spark mini as a booster, but that's got a fixed EQ shape. The bigger TC Spark has T and B controls as well as a gain and level control for adding some extra drive as well.

The EH Screaming Bird booster is cheap, but has a fixed frequency boost, so it will be something that works for you, or it won't.

You could always amuse yourself during the long winter nights by making a Rangemaster treble booster clone kit. You can get them from under £20.

I've never used a Laney VC30 so don't know quite how it will respond. I've got a Laney Ironheart 30 combo and that does clean and drive very well and has it's own boost feature built-in, but have no idea if it would respond in the same way as the VC30 as it has 6L6s.
User avatar
Wonks
Jedi Poster
Posts: 8954
Joined: Thu May 29, 2003 12:00 am
Location: Reading, UK
Correcting mistakes on the internet since 1853

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Wonks » Sat Jan 26, 2019 7:49 pm

Have you ever tried changing the valves, pre or power? The output valves may benefit form being replaced if they are quite old, the preamp valves if they aren't quite as 'premium' as the marketing blurb said.

It may even be as simple as checking the valve biasing and getting that adjusted if it's out.
User avatar
Wonks
Jedi Poster
Posts: 8954
Joined: Thu May 29, 2003 12:00 am
Location: Reading, UK
Correcting mistakes on the internet since 1853

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby ef37a » Sat Jan 26, 2019 8:43 pm

Valves and biasing, yes Wonks. The schematic shows a 56 Ohm as the shared cathode bias resistor. It might be wise to check the amp in the dark for any sign of "red plating" indicating the valves are being pushed past their design limits and may not help the tone either.

I have found 68 Ohms removes any risk with any brand of EL84 that I tried.

Has to be said, the 84 is not THE most reliable or long lived output valve and in these cathode biased amps they are working their nuts off all the time even when you are not playing.

Dave.
ef37a
Jedi Poster
Posts: 10528
Joined: Mon May 29, 2006 12:00 am
Location: northampton uk

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Folderol » Sat Jan 26, 2019 9:37 pm

I'm a bit out of date but remember in domestic stuff EL84s ran very hot and tended to have comparatively short lives. Everyone I knew thought it was a stupid amount of power to pack into such a small envelope. In that environment they were nearly always run common cathode biasing and very often the valves were not matched :(
User avatar
Folderol
Jedi Poster
Posts: 8613
Joined: Sat Nov 15, 2008 1:00 am
Location: The Mudway Towns, UK
Yes. I am that Linux nut.
Onwards and... err... sideways!

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Wonks » Sat Jan 26, 2019 9:52 pm

The Swan Vesta EL84s were. ;)
User avatar
Wonks
Jedi Poster
Posts: 8954
Joined: Thu May 29, 2003 12:00 am
Location: Reading, UK
Correcting mistakes on the internet since 1853

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby ef37a » Sat Jan 26, 2019 10:13 pm

Folderol wrote:I'm a bit out of date but remember in domestic stuff EL84s ran very hot and tended to have comparatively short lives. Everyone I knew thought it was a stupid amount of power to pack into such a small envelope. In that environment they were nearly always run common cathode biasing and very often the valves were not matched :(

Quite. If I was to build a 30ish watt amp with cathode bias I would use 4 6V6s, a valve that has proved nigh on indestructable. They were common in radios and the similarly rated EL32 just did not last as long. Bell &Howell projectors used two V6s and they lived forever despite the heat, some very out of spec speaker loads and the constant pounding of the mechanics.

And yet, I cannot think of a guitar amp powered by such a quartet and even 15 watt 6V6'ers are rare.

Dave.
ef37a
Jedi Poster
Posts: 10528
Joined: Mon May 29, 2006 12:00 am
Location: northampton uk

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby John Egan » Sat Jan 26, 2019 10:22 pm

Hewesy wrote:Now I love the amp, it does that "chime" thing very well and the clean sound is great but it just doesn't offer the warmer, crunchier drive that I'd like, which seems to be a similar characteristic to most "classic" amp circuits based on EL84 (such as the AC30 it's modelled after).
Hewesy

If you can, try the Fulltone GT-500 pedal. It has a booster and a distortion pedal, individually adjustable and with the ability to change the order so that the booster can come before or after the distortion, Alternatively, you can use either on its own. It doesn't get too bass heavy and has its own EQ. It's really versatile.

Regards, John
John Egan
Regular
Posts: 299
Joined: Wed Nov 27, 2002 1:00 am
Location: Staffordshire, England

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Hewesy » Sun Jan 27, 2019 12:47 pm

Thanks John, I'll add that to the demo list. I was looking at the D&M drive which seems to be a similar concept so that's worth a look too.

I revalved it with matched sets about 18months back and it's had light use since. Interestingly the previous owner had changed the preamp valves on the drive side to try and get more drive, swapping back to stock made very little difference. Perhaps it is due a bias, I'll see if we have a local person to do that.

The HT Dual did pop up but I have a HT Drive which has way to much gain for me, even with the gain as low as possible. Perhaps the Dual has a "cleaner" side. As a side note though I do use the HT Drive with full volume and no gain for recording bass. Adds a nice SVT type growl on a P bass.

Wonks I had looked at a Spark Mini but the full might be a better bet so I can tame some treble, another for the demo list.

Much appreciated all,

Hewesy
Hewesy
Frequent Poster
Posts: 752
Joined: Tue Oct 19, 2004 12:00 am

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby CS70 » Sun Jan 27, 2019 12:53 pm

To understand, which kind of sound are you after? Do you have some reference track etc?
User avatar
CS70
Frequent Poster (Level2)
Posts: 3910
Joined: Mon Nov 26, 2012 1:00 am
Location: Oslo, Norway
Silver Spoon - Check out our latest video  and the FB page

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby ef37a » Sun Jan 27, 2019 1:01 pm

Hewsey, the Dual has straight through (but buffered. None of your "true" bypass nonsense here!) , OD with gain control and a "crunch" button that just adds..well, CRUNCH! Whatever TF you take that to mean.
In short, just about as much EQ, gain and volume control as you will likley get in one pedal. Plus of course the OD come from a valve.

There is a solid state version of all the HT pedals. Said to be pretty good (I'm no judge) and they are conventional in size and power requirement to most pedals, i.e. PP3 9V.
They cannot of course compete with the massive headroom of the HTs with their 30V LT and 300V HT supplies.

Dave.
ef37a
Jedi Poster
Posts: 10528
Joined: Mon May 29, 2006 12:00 am
Location: northampton uk

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby ef37a » Sun Jan 27, 2019 1:03 pm

CS70 wrote:To understand, which kind of sound are you after? Do you have some reference track etc?

GOOD idea C! Well, not for me...Obviously!

Dave.
ef37a
Jedi Poster
Posts: 10528
Joined: Mon May 29, 2006 12:00 am
Location: northampton uk

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby John Egan » Sun Jan 27, 2019 2:19 pm

Hewesy wrote:The HT Dual did pop up but I have a HT Drive which has way to much gain for me, even with the gain as low as possible. Perhaps the Dual has a "cleaner" side. As a side note though I do use the HT Drive with full volume and no gain for recording bass. Adds a nice SVT type growl on a P bass.
Hewesy


These two pedals : the Thomas Blug XVive Tube Squasher and the JHS Mike Campbell Calhoun both seem to do nice low gain tones. I'm interested in them myself, but I've managed to resist - so far.

https://www.youtube.com/watch?v=YCjRlH4laKg

https://www.youtube.com/watch?v=r_kyCHrrnwE

Just a thought.
Regards, John
John Egan
Regular
Posts: 299
Joined: Wed Nov 27, 2002 1:00 am
Location: Staffordshire, England

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Wonks » Sun Jan 27, 2019 2:35 pm

The Tone City Golden Plexi does a pretty good Marshal style crunch, https://www.andertons.co.uk/guitar-dept/guitar-pedals/tone-city-golden-plexi-overdrive-pedal whilst the Tone City Black Tea https://www.andertons.co.uk/guitar-dept/guitar-pedals/tone-city-black-tea-distortion-pedal-%28excluding-power-supply%29 does what is supposed to be very driven AC30 tones, and does sound a bit sweeter than the Golden Plexi. Max preferred the Black Tea. Neither are expensive. I've had both (but I think I've given them to a mate) and both sounded fine through clean amps.

Both those pedals sound quite similar, so I didn't want two that were almost the same and I stuck with an Xotic SL drive for a Marshal drive sound which was only a tiny bit better than the Golden Plexi.
User avatar
Wonks
Jedi Poster
Posts: 8954
Joined: Thu May 29, 2003 12:00 am
Location: Reading, UK
Correcting mistakes on the internet since 1853

Re: Valve preamps, powers amps and a possible rabbit hole...

Postby Hewesy » Sun Jan 27, 2019 9:44 pm

Thanks Dave, I did buy the LT Drive after our last conversation and it is a lovely thing indeed (yep here it comes) but it does have an EQ bump which can be a bit annoying. I'll check out the HT Dual though as I can find those locally. The HT Drive doesn't add the same EQ bump.

Track wise I'd be very happy to get close to the Paul Weller Stanley Road tone, essentially a humbucker based guitar (SG or Casino) and a Marshall Bluesbreaker. I have an SG/Aria TA but mostly play a Humbucker Strat (Blacktop series). Ok so the VC30 isn't the closest amp to have choosen but the warmth of the clean channel sold it to me.

Thanks Wonks, for the price that seems a logical start and hopefully point me one way or another. Buying both is cheaper than the Victory...

Cheers all, plenty to Google and try.

Hewesy
Hewesy
Frequent Poster
Posts: 752
Joined: Tue Oct 19, 2004 12:00 am


Who is online

Users browsing this forum: No registered users