Mikey R

Cheers guys!

Hey everyone, I wanted to say hi before I start posting again. I've been away from the site, looking after real world stuff for a bit. Life got tricky, and it demanded all my attention for a bit. I've been playing bass for about 25 years now, it's always been there in the background. Like many of us, I've accumulated a bunch of paraphernalia, but since I've all my music projects are on hold, I'll be moving on all the stuff I've no real attachment to.

They put bass through the FOH??!! Thats news to me!

Are you using a daisy chain power supply, or one where each pedal is isolated from the rest? Do any of your pedals need a ground, or are they all ground lifted? Eliminating ground loops is something I'm reading about at the moment.

In some cases, such as some of the less expensive iphone docks that were popular a couple years ago, the preamp valve was nothing more than a marketting gimic. We know a large part of the valve tone comes from the interaction between the power pentodes, the output transformer, and the speakers, a single preamp triode won't simulate that. Yes, there is a psychoacoustic effect of all those nice harmonics. It doesn't necessarily matter how those harmonics are generated. But it's proven to be very difficult to get it dead on, in a way that not only gets the harmonic content right, but also the timing and phase of those harmonics. You don't only need to trick the ears of the listener, you need to trick the ears of the player, who is well within the feedback loop of ears to brain to bass to amp to speaker back to ears. Interestingly, the best amps to play aren't necessarily the best amps for the mix.

Hi Luke, it depends on how linear the amp is, or how soon the overdrive kicks in. But eventually, every amp of every class will hit the upper limit set by the supply rails, even the most linear. When that happens, theres nothing to stop it from clipping. I suppose, if your amp had a limiter, then that could prevent this from happening.

"It's all I need" - never before have I heard these words on BC!

I clearly didn't get the memo. I nearly have as many amps as I do guitars. Thats fair enough. I've been away for a while, and have missed out on shifts in the BC culture during that time, and what has and hasn't been flogged to death. When I used to read the Luthiers Corner on Talk Bass, there were sigh inducing reruns of tonewood discussions almost weekly, with as much misinformation circulating as there are on the merits of values vs transistors. The very reason I came here to guage the general feeling of valve kit, is that the BC bunch do sniff the corks, they are the kind of players who enjoy experimenting with top of the range kit, and they are a good representation of the kinds of players a small boutique company would target. The premium kit is subject to fashion, and fashion changes over time. I just wanted to check that valves and hybrids haven't gone out of fashion, because that would be a real shame. They're also a really nice bunch who are happy to share their experiences, of which we have amongst us a huge stockpile.

Hi Luke. I don't think anything you said was wrong, but I do believe that the power output of class D amps is calculated differently, and therefore is inflated relative to how valve amps are rated. I do believe valve amps are rated at continous sine wave output, as that is how the output stages of radios were tested back in the 50s. The limit for any amp is how much juice the power supply can, erm, supply. In class AB, this sets the maximum voltage swing, but also how that voltage sags as current is drawn. If the voltage doesn't sag, then the power output can be maintained infedinitely. The rating system changed sometime in the 70s or 80s, and things like peak power output were invented to make hi-fi amps seem louder on paper. Some of this would have leaked into instrument amp specs, as transistor output stages became popular. I'm going to have to google "peak programme" and remind myself of all of this. Then class D came along, and they are complicated beasts. OEMs buy their output boards wholesale, meaning that they have very little control over what is in their amps. If they use a 300 watt board originally designed for a car stereo, then they'll rate their amp at 300 watts. It may be able to handle very short bursts of 300 watts during the loud sections of classical music, but it couldn't keep that up if the signal was all bass guitar. So, I don't think we are comparing like for like, even if we remove the effects of how valves compress as they are driven into clipping. I'd also point out that modern valves don't kick out as much juice as NOS valves do. A 6550 pair, with 600 volts on the anode and 300 volts on the screen, dring a 5k anode to anode load, used to output 100 watts. If you use modern valves, you'll get around 70 watts, you need to increase the screen voltage to 400 volts to get the full 100 watt output, and that would be very hard on the valves. Even so, modern amp builders still rate their amps as if they had NOS valves, even though they don't ship with them. Your 100 watt amp is actually kicking out 70 watts, and it's still louder than a 300 watt class D.

Hi xgsjx, would you find any amp more useful with a DI? What is your opinion on effects loops, yes or no? If yes, what do you use them for? Cheers! You can own something nice, and only bring it out for special occasions. Many of us here have several basses, and play them all, even though we might only use the one for live work.

Hi Muzz, I agree it's subjective, which is why I'm asking for people's opinions. I want to know if there are people out there who do like valve and hybrid kit. I'm sorry you're not finding this conversation it useful, I can assure you that I am. Hopefully, I'll be able to explain why in a few weeks.

You're touching on psychoacoustic effects there. A real experiment would have to be very complicated. But as a starter for 10, you could connect a 4 ohm dummy load across the output, and connect a a 440hz square wave from a function generator to the input. That way, clipping will have minimal effect - the signal is already clipped. Increase the input until the voltage across the output doesn't increase any further. The voltage across the dummy load squared divided by 4 would then tell you how much power the amp is putting out at 440hz. Ideally, you'd repeast at 220, 110 and 55hz to get a fuller picture. This will give you continuous power output. To get peak power output, you would have to drive the input with pulses of waveform. It's not perfect, but it would give you an idea of how the two amps fare objectively. I wouldn't be surprised if the class AB amp does better in continuous output, by quite a margin. Thanks Artisan! Thats exactly the feedback I wanted to hear. I wanted to know that there are at least some people out there who "get" the value amp thing. OK, now I'm showing my bias, I'm also a valve guy.

A 30 watt amp is feaking loud when cranked in your front room. 200 watts would show up on the Richter scale. EBS used to make a 90 watt all valve amp, that's likely the right number of watts to give enough loudness, whilst being on the edge of soft clipping. I wonder why they took it out of production? Are people not interested in valve kit any more? Do people not like to clean and jerk their heads onto their speaker stacks? EDIT: I just checked, Ashdown do still make their CTM-100, but they've given up on the bigger valve amps. The 300 and "big block" 427 are long gone. Snarf.

Hey Mert. With a 200 watt power section, you might never have the chance to push it till it to compression. So, since both amps were in their linear range, that would explain why they sounded similar. Pushing a 200 watt amp to clipping is face meltingly loud.

Hey everyone. I'd like to steer the conversation a little, if I may. The excellent point has been brought up, that the technology and class of the amp isn't important, how it sounds is. I totally agree with this. We don't listen to technical specs, we listen to music. However, we can draw on our experience, we can say amps of that type tend to sound like this, and I like this sound, so I bought an amp of that type. We've also ascertained that class D amps are quite popular, provided you can get one big enough for the job. Class D watts seem to be less loud than class AB watts. I'd now like to discuss peoples experiences with valve amps, in particular if anyone has done an A / B comparrison of a transistor vs a valve amp. I'd like to get peoples ideas on the whole experience - not just the sound, but the whole feeling of playing through valves. How they respond and how the sound interacts with your playing. Is there truth to the idea that valve amps are more "interactive," is the mojo real or just in the mind of the player? Is the real thing better than simulated tubes, or are the sims just as good? Final question, for now at least - would people considder buying an amp with a nice tone for studio use, or as a bedroom blaster, and maybe have a bigger but less nice amp for live work? Kind of like having a nice classic bass that you don't let leave the house, for gigging you use the old beater bass? Us lot on here tend to like having nice things, even if they're impractical. Is a nice amp a thing that people want?

Cheers for the input Al! The poll is really there just to spark a bit of conversation. Your data point adds weight to my inference that class D amps are great, provided you get one big enough. I'm seeing recommendations from 500 watts up to around 900 watts for live use, whereas a couple hundred watts of class AB would previously have been fine. I'd love the opportunity to compare them using a dB meter, against a tranny class AB and a valve AB amp of differing power outputs.

Oh, and also, valve amps can also be really clean. We associate them with grit, but they aren't all gritty.

Well, we know that class AB valve amps are loud for their rated output, relative to the same rated transistor AB amp. I've no doubt, if you compare a 100 watt valve bass amp with an 800 or 900 watt class D amp, then the class D will keep up. And, if you can't tell the difference in a band situation, then theres no reason not to go with the class D. I'm purposely not giving my opinion here, as althought I don't mind guiding the discussion, I dont want to overly influence it. Blood in my mouth beats blood on the ground... ;o)

I do believe my old Trace had a switch to let you choose where the EQ went in the chain. But if you did want an amp that was so configurable that it could do everything for everybody, then it would be incredibly complicated and difficult to use, as well as expensive and potentially noisy. The Fender Cyber Twin died because of this. I keep contrasting bass amps with guitar amps here, since both bass and guitar valve amps share a common ancestor, a lot of the technology is the same. Of the common classic bass amps, only the SVT really diverges from the topology used in guitar amps. I don't remember if the original SVT allowed you to plug stuff in between the preamp chassis and the power amp chassis, though I bet plenty of people would have made this mod if they'd have needed it.

They can still both be quite gritty amps, with a bit of snarl when you push them hard. There's nothing that says transistors can't add grit, they just do it slightly differently. Amen! Have you ever had the opportunity to compare your big old tranny power amp to a valve power amp? At a bass bash, maybe? Class AB transistor amps are a different beast again to class D amp, I've not yet played a class D that I liked.