Paddy Morris

Thanks. Just to say once again that the slap is not overloading my preamp. Everything is nice and clean until the output stage. But I take the point about my technique, which I'm always trying to improve on. I've been playing for 42 years, but it's still a journey. I guess in that time I should maybe have tried a valve output stage amp, eh?

Thanks Bill. I think I said somewhere earlier, a fast attack peak limiter does fix the problem. But it does also really hobble the sound I get. I've been through a fair few dynamics control devices and the soft knee / fast attack setting on a Keeley compressor pro is the best compromise I have found so far. But I still prefer the sound with it switched out entirely. So I was wondering if a valve output stage would handle those transients more gracefully. I guess the best way is to try it and see. I'm sure I know someone who will lend me an Ampeg or HiWatt head for a few hours.

Thanks. In fact I have had issues with clipping and overloading further upstream in the past, but I've managed to iron them all out. This is definitely a problem in the final power stage. If I take a feed of the DI output from the amps then the problem isn't present. Also if I put a fast attack limiter across the amp input the problem goes away, but then also so does all the attack on my transients. And I miss them.

Hiya. Yes, I'm HPF'd to within an inch of my life. Apart from any other reason I can't really hear my intonation on a loud gig unless I have rolled off all that LF junk. I suspect I need to just take my rig (and my poor credit card) to some dealer who keeps a good stock of all-valve amp heads.

Well, it may be going over old ground, and if it feels a bit tedious then I apologise. But I have found it really useful and am very grateful to everyone who has contributed. Really interesting to hear the technical and quasi-technical reasons behind it all. I'm an upright player. When I put my Fender P through any of my class D amps I'm really happy with the result. The trouble comes when I'm playing slap upright against a drummer who has had a bad day and is taking it out on his drums. The transients from the slapping play absolute havoc with the amp headroom. I have to put a fast attack limiter across the input to stop the amps cracking on the transients in the most horribly digital way you could imagine. With smaller powered amps the Class D module goes into protection mode for 2 seconds at a time, and the 800w ones just break up. The limiter fixes the problem but completely castrates the sound of the instrument. At lower volume, without the limiter, the sound is pretty much what I want (when I'm playing the right notes!) I don't want a valve crunch sound or even any more warmth, as I already spend a lot of time dialing out the excessive warmth of the intrument. All I need is something that will deal with those transients at a reasonable volume without making a horrific noise. The guitarist is a valve junkie, and he's gradually wearing me down.

Thanks. Sorry if this feels like valve amp principles 101, but I disappeared down a rabbit hole when I saw Mesa stating that valve power stages are 'more powerful' rather than just subjectively louder.

Ah. Ok. That does make sense. Thanks Bill. But so in that case if you drive the valve front-end of a hybrid amp quite hard, and get all that soft clipping and compression, is the class-D power stage ok? Why would you need a valve power stage too?

Thanks Matt. Good to know. But I wonder what the reason is, if it isn't actually the electrical power in watts.

Sorry if this subject has been done to death in the past. I have been using Class-D amps for quite a while now, and like them a lot. But they don't really seem to appreciate being driven close to their limits. So I've started looking at a few tube power stage amps, and a lot of the marketing blurb seems to say that they are 'more powerful' per given RMS wattage. I had a training in electronics (quite a looooong time ago) so I get that in a physical/electrical sense this has to be untrue, except for amplifiers where the manufacturers tell all sorts of fibs about the power output, and use terms like 'peak power', or 'music power', and avoid quoting an actual RMS or AES power rating. But I was wondering if players had found that in the real world it does actually turn out to be the case that a tube output stage gives you more apparent loudness per specified RMS watt? In particular, I was looking at this text from the Mesa-Boogie site. "NOTE: Tube Amps sound as loud as Solid State Amps rated at several time their power (wattage) rating. Choose from 8 tubes producing 465 Tube-Watts (sounds like in excess of 900)" It's a bold claim to make if it's just plain untrue. So are they talking about the 'warmth' or harmonics, or saturation, or the soft clipping of the tubes at high power? Or the fact that you can run the tubes much closer to their supply rails?

I think, impedance-wise a 4 x anything is usually wired to give you 8Ω//8Ω = 4Ω in series with another 8Ω//8Ω = 4Ω to give you a final 8Ω load. So the Elf will be supplying the same sort of power into your 8Ω rehearsal room speaker as it will into your 8Ω Super Mini. I have a Super Mini T and they are really very efficient, so I'm guessing that your gigging volume will be louder than the rehearsal room volume. But you probably won't get the same low end on the Super Mini as your 4 x whatever cabinet. So you might end up screwing more EQ into the Elf, which might in turn mean you get less overall volume. I've also heard that some cabs don't sound sweet when underpowered, but that's certainly not true of any of the newer generation of Barefaced cabs. The sound is very consistent across all volumes until you start to reach the limits of the speaker (which you certainly won't be doing.)

I would be tempted to take the electronics and chassis of the Crate and mount it in a different, maybe larger enclosure. Or have you considered a PJB double-four? I have used that with upright bass for busking type gigs, and you can run them from a powertool battery.

For what it's worth, I also think the Genzlers are awesome. I haven't tried the Kinetix, tube/hybrid thing, and they aren't cheap, but in the demo videos they sound fantastic on funk stuff. But if you can pick up a 2nd hand Magellan you won't be disappointed. Just a small number of front panel controls is enough tone-shaping to give you virtually any sound you want. Either the 350 or the 800. I have tried both the Warwick Gnome and the TE Elf, and once you get over the initial 'oh my god, isn't it tiny?' vibes, neither of them is much use except in an absolute emergency. The tone shaping on both just lacks flexibility.

Yeah. If I'm using the click pick-up at all, then the gain is as low as it will go, and even then I can hear it clipping from time to time. I use a Vicks pickup for fingerboard now, which has a slightly lower output and works fine (though I hardly use it.) The bridge channel still seems to need to be at a low gain setting, but doesn't seem to distort. I guess it must vary a lot depending on the liveliness and volume of an individual instrument, and the player's technique and style. I think it's fair to say that I'm not particularly subtle when I'm playing slap! I have toyed with the idea of knocking up a pair of resistor pads to take about 10dB of the pickup signal before the input stage of the preamp. But I also don't want to create yet another potential failure point at a gig. But notwithstanding all of this, I still think the RB Pro rig is incredible for the money.

The headroom on the preamp seems to drop away long before the battery light comes on, so it's always worth trying a new battery. Also make sure the input gain is set to the minimum.

Zak Victor does a good bridge wing pickup. I've found it to be less boomy than the J-tone and pretty feedback resistant. https://www.uprightbasspickups.com The best pickup I have is a Yamahiko mounted on the bridge of my carved bass. But they're pretty pricey by the time you've paid import duty from Japan, and you need to get a luthier to fit them properly. https://yamahiko.info/product/contrabass/ The most realistic and 'airy' thing I have is an Ischell contact mic. French, and also fairly expensive. Really captures the essence of the bass, but really prone to feedback.