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  #1  
Old 11-25-2012, 07:09 PM
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So what's the difference in a "good amp" and a "bad amp"?

I did a search and turned up nothing exactly like this, but if there is a thread please link me. Thank you.

I'm talking real nuts and bolts here. What kinds of components, in general, are different in well-built, high-quality amps as opposed to cheaper amps. I am studying electronics in school. To me, a resistor is a resistor (other than tolerances). But on an electronics level, what kinds of things are used in better sounding amps that aren't used in lower quality amps?

And while we're on the subject, why is hand wiring such an amazing thing? I have had my hands on hundreds of circuit boards, both hand wired and machine wired. And to me, ones done by robots are almost always neater, and have great connections. I have had to "fix" many more problems on hand wired stuff than I ever have on machine wired boards. Granted, my experience is still very limited, but I wish someone would tell me what the hype about hand wired is, in REAL electronic terms and not just romantic ideals. Don't get me wrong. I'm not knocking the craftsmanship and pure intellect that goes into sitting down with a bunch of parts and making a sweet sounding amp by hand out of that pile of parts. It's impressive. But is the finished product BETTER just BECAUSE it was hand wired? (I'm not arguing a point. I truly don't know so I'm asking.)


By the way, I understand market positioning, brand name, "boutiqueness" and all that. I'm not interested in a conversation about how brands have managed to overprice their products. When I say "better" I literally mean amps that sound better regardless of price point or past reputation.

Thanks!
  #2  
Old 11-25-2012, 07:30 PM
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It's an overly vague question. If an amp performs well and lasts through thorough use, it's good. Different brands have different reputations, but virtually none are 100% consistent.

Opening up an amp to assess it based on componentry is tricky, since good components aren't necessarily utilized best in the design. Tube amps are easiest to identify as good or bad based solely on the simplicity and quality of componentry, but I've found the difference between class D amps is really pretty minimal, regardless of price.

Point-to-point wiring offers a significant advantage over printed circuits in simpler tube designs, but the more complicated the circuitry, the more PCB's make better economic and practical sense. Even though a design type could bear improvement, doesn't help if it's prohibitively costly.

But really your question needs some narrowing down. Around here, as with all forums, if you want wide-ranging unhelpful answers, ask a vague question.
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  #3  
Old 11-25-2012, 07:52 PM
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Quote:
Originally Posted by two fingers View Post
I did a search and turned up nothing exactly like this, but if there is a thread please link me. Thank you.

I'm talking real nuts and bolts here. What kinds of components, in general, are different in well-built, high-quality amps as opposed to cheaper amps. I am studying electronics in school. To me, a resistor is a resistor (other than tolerances). But on an electronics level, what kinds of things are used in better sounding amps that aren't used in lower quality amps?
In addition to tolerances, some components have "parasitic" or non-ideal behaviors that have to be understood and controlled. Higher quality amps also tend to be somewhat over-designed in terms of ratings, such as working voltage and wattage. There are low- and high-quality printed circuit boards, and widely varying quality of anything remotely mechanical such as pots, switches, connectors, etc.

Quote:
And while we're on the subject, why is hand wiring such an amazing thing? I have had my hands on hundreds of circuit boards, both hand wired and machine wired.
In the tube amp arena, there are folks who feel that point to point wiring is more repairable than printed circuits. Also, pure craftsmanship still has a certain appeal.

Unless you want to pay through the nose, most board makers will use a combination of machine placement for components with standard outlines, and hand soldering of large components.

As for printed circuits, one could fill a book with advice and "tribal knowledge" about getting quality boards designed and made. For a lot of small-time gear makers, it's simpler and cheaper to stuff and solder boards by hand than deal with all of the costs and pitfalls of getting fully assembled boards made.
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Last edited by fdeck : 11-25-2012 at 07:54 PM.
  #4  
Old 11-25-2012, 07:55 PM
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Mostly on valve amps since that is what I do:

Resistors make thermal noise, it can be an issue with old carbon comps, and carbon comps have a resistance that varies slightly with voltage, which gives a little bit of distortion some people claim to hear.

Layout is really important for noise too, and a good layout tends to be expensive, as you need to separate things, which disagrees with PCB construction. Lead dress is another thing for noise, its a skill, so no good for mass produced things, the wiring work in Hiwatts is art.

A lot of other stuff is maintenance. Decent thick PCB with decent tracks is ok to work on. But turrets are a joy to work on. Point to point is a nightmare of mess since the circuit isn't laid out in a sensible way. PCB is good for some parts, but any moving parts like sockets and pots and valve bases attached to them are failure points. Best construction style I've seen is the Matamp turret track system, where a pcb carries the tracks, but the components are on turrets so are easy to get at and can heat and cool without stressing anything else, and no worries about wires falling off the back of the board.

'Hand wired' thing is down to some internet loudmouth constantly referencing it as a good thing, along with 'point to point', using both of those things in the wrong context. There is wired well, and wired badly, whether by hand or machine. chances are with machine, it will be done with lead free solder, which is a compromise, military, NASA, and high voltage stuff is still allowed to be in lead, because it is better. Plenty of handwired stuff is done shoddily, nasty spaghetti mess style, again see old Hiwatts and new Matamp, and John Chambers work for proper hand wiring. People generally think 'hand wired' means 'not pcb', which is as wrong as the assumption pcb automatically means worse. there are a lot of cheap nasty PCBs out there though.
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  #5  
Old 11-25-2012, 08:18 PM
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First resistors vary in advantages and draw backs, that is why there are carbon composition, carbon film, metal film, metal oxide, ceramic wire wound, non-inductive wire wound as examples. Just like a cap is not just a cap or inductor is not just an inductor.
Manufacture matters also, I dislike buying one brand of HV electrolytic caps due to high failure rate.

As far as construction methods, hand point to point is an art and inter-circuit crossover can be dealt with by adjusting lead dress unless gross errors have been made. If with PCB layout you fail to see a potential inter-circuit interference, you may have to scrap and start over. Quality of PCB substrate and quality/thickness of contact material add into the quality of the final product.
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  #6  
Old 11-25-2012, 09:19 PM
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  #7  
Old 11-25-2012, 09:54 PM
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Meh. My Peavey's guts are probably pretty unexciting to look at, but it works when I turn it on.
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  #8  
Old 11-25-2012, 10:39 PM
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Aside from what's already been said, transformer quality can vary hugely between different amps. There's a lot of money to be saved by throwing one together out of old frying pans and bailing wire, instead of well-sourced materials put together under strict tolerances and properly shielded.

On the topic of hand-wiring, this article by Mesa isn't a bad one.
  #9  
Old 11-26-2012, 08:33 AM
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Originally Posted by Mehve View Post
On the topic of hand-wiring, this article by Mesa isn't a bad one.
That totally is a bad one. It assumes by 'handwired' you mean 'cheapo Fender'. And it constantly references tag board not point to point anyway, the whole idea of point to point is barely any wires, because the components go from point to point. Handwired well can be totally consistent. It just requires skill. It doesn't have to be on porous fiberboard eather, that is a Fender cheapout, you can mount turrets on same of better board than Mesa use for their PCB.
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Last edited by Mr. Foxen : 11-26-2012 at 08:35 AM.
  #10  
Old 11-26-2012, 09:01 AM
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The difference in good and bad is totally in the ears........for me, it's tube vs. solid state.

And I realize that is completely a personal taste thing but my Fender Bassman tube amp sounds so much better than any solid state amp I've ever heard that I will never hear an argument that will convince me that solid state can compete.

Flame on!
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  #11  
Old 11-26-2012, 09:10 AM
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When its a reliability issue, the difference in the ears is hearing sound or not. Or the clicky pops sound of cracked solder on pcb mount pots.
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  #12  
Old 11-26-2012, 09:17 AM
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Originally Posted by Mr. Foxen View Post
That totally is a bad one. It assumes by 'handwired' you mean 'cheapo Fender'. And it constantly references tag board not point to point anyway, the whole idea of point to point is barely any wires, because the components go from point to point. Handwired well can be totally consistent. It just requires skill. It doesn't have to be on porous fiberboard eather, that is a Fender cheapout, you can mount turrets on same of better board than Mesa use for their PCB.
Yes, it's promotional, and they do focus on the worst of the other side. But not entirely without reason - there are a lot of "hand-wired" amps with exactly those kind of shortcomings. For every work of art and engineering, there's nine other abominations. And just as the Mesa article says, consistancy is harder, and you pay for that difficulty in labour. I myself use a Woo Audio headphone amp, it's a thing of beauty inside. But I've had more than a few rat's nests inside amps as well.

As far as reducing wires, that's down to circuit design. P2P or PCB doesn't magically reduce the number of wires, it simply determines how a given circuit is assembled. If you design a simpler circuit, that certainly has the potential to benefit a P2P construction more, but it's not like a simpler PCB is going to be a bad thing either.
  #13  
Old 11-26-2012, 09:27 AM
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It implies the difference is between pcb and point to point (whilst actually describing something that isn't point to point), and that is totally wrong. Neither method has any bearing on construction quality, that is a separate factor. And having been inside Mesa amps as a tech, their construction is nothing they should be boasting about. The classic bass stuff isn't so bad because its a simple circuit suited to that sort of thing, but the fiddly million knob guitar things are a mess. They've put the expensive labour where they don't have to pay for it.
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  #14  
Old 11-26-2012, 10:18 AM
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An amp is "good" either because people want it regardless of it being technically superior or not, or because it's technically superior, which doesn't necessarily make people want it. Different brands have different goals.

Quote:
What kinds of components, in general, are different in well-built, high-quality amps as opposed to cheaper amps. I am studying electronics in school. To me, a resistor is a resistor (other than tolerances). But on an electronics level, what kinds of things are used in better sounding amps that aren't used in lower quality amps?
Some types of parts keep signal distortion and noise to a minimum, but are not necessarily expensive. Some types of parts look cool and may or may not be expensive, but also may or may not have superior audio performance.

One thing that adds cost is the tolerance of the components. A +/-2% capacitor is a lot more expensive than a +/-5% capacitor. The same thing goes for a 5% vs 1% vs 0.1% resistor.

Film caps are more expensive than ceramics, but sometimes ceramics are better. Silver mica caps are more expensive than film, but sometimes film is better.

When it comes to power supply circuits, over-design can be a good thing to improve reliability. I would stay away from "over-designed" audio circuits where ridiculously over-sized parts are used for looks because that hurts audio performance. Larger components have larger parasitics.

Since you brought up resistors, use metal film resistors for audio. Never use a tantalum capacitor to pass a signal. You'd want to avoid using ceramic capacitor in certain types of audio circuits. There's a lot of info out there...

Quote:
And while we're on the subject, why is hand wiring such an amazing thing?
Because it looks cool and adds an old-school vibe to the construction. I enjoy building hand wired amps, even though I know that I could make a more hi-fi version of the same thing with a good PCB layout. Some of the character of vintage amps comes from the not so great, hand-wired layout. Sometimes PCB layouts are screwed up on purpose to capture that. Some hand wire jobs are really pretty, but going for that OCD look can hurt audio performance in the same way as using unnecessarily large components. You get better consistency with a PCB layout. The layout is way important, whether or not there's a PCB involved.

PCB's have gotten a bad rep. when it comes to tube sockets, input jacks, pots, and misc. electromechanical solder points. I saw those as common failures when I worked as a repair tech. A double-sided PCB with plated through holes eliminates those problems.
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  #15  
Old 11-26-2012, 10:53 AM
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This is exactly what I was hoping for guys! Sorry the topic was so broad. But I was kind of looking for broad answers at this point in my education. Thanks to all for your contributions so far!
  #16  
Old 11-26-2012, 11:11 AM
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Maybe your question was broad, but it was a good question. As a bassist and former audio technician with a specialty in guitar and bass amps, I can identify with the old adage, "you get what you pay for." More expensive gear will have better circuit boards and/or use point-to-point wiring for the tube sockets due to heat. Solid state amps will use better, more costly components which are overrated for the output circuitry to handle occasional abuse or "full throttle" use. With tube amps, it is all about the quality of the power and especially output transformers. Tubes are important also - - matched sets of output tubes and more expensive, quieter preamp tubes selected for those purposes will make a difference in both your ears and those of the listener. This is a pretty simple answer for your question, but I think it grabs the gist of it. And just as important, the product may be well-made, but it also needs to sound well. Your ear will ultimately tell you what you want to know, next to your research on quality.
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  #17  
Old 11-26-2012, 11:23 AM
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Originally Posted by Bassman12350 View Post
More expensive gear will have better circuit boards and/or use point-to-point wiring for the tube sockets due to heat.
More money might buy the manufacturer better stuff, but since they can stick whatever price they like on it for the consumer, it won't buy it for them. Entirely PCB mount Orange amps are about the same price as really nicely made Matamp equivalents.
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  #18  
Old 11-26-2012, 10:55 PM
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BbbyBld that's a ton of info in a relatively short post. I'll be Googling for days.

Thanks again everyone.
  #19  
Old 11-27-2012, 10:31 AM
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Quote:
Originally Posted by two fingers View Post

I'm talking real nuts and bolts here. What kinds of components, in general, are different in well-built, high-quality amps as opposed to cheaper amps. I am studying electronics in school. To me, a resistor is a resistor (other than tolerances). But on an electronics level, what kinds of things are used in better sounding amps that aren't used in lower quality amps?
...
There is still a lot of counterfeiting going on. Two components may look the same but one may be fake. It may or may not make a difference in sound. It may only effect failure rate. The difference may never show up.

Counterfeiting has been going on as long as there are components to copy and make a profit.

If you're a manufacturer on a higher supplier picking order, you have a higher chance to get real parts.

All the routing these days is done by software long before hardware gets involved. Stupid mistakes just rarely happen. There are billions more highly complex electronic devices in use today that demand accuracy and reliability. Hand Wired is a gimmick for old style circuits that aren't easy to automate. You will never see "Hand wired" cell phones, or TV's. It's not like it's still a career to be someone who can hand wire.

During actual automated building there are many checks taking place, including x-ray of the complete board looking for hidden failures. A person being so careful may be slow and get replaced.

It's a good time to be learning electronics. You can build, test, and troubleshoot complex circuits long before committing hardware. You'll be stuck with terms like "hand-wired" for as long as someone believes the marketing that it's somehow important.
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  #20  
Old 11-27-2012, 10:49 AM
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Hand Wired is a gimmick for old style circuits that aren't easy to automate. You will never see "Hand wired" cell phones, or TV's. It's not like it's still a career to be someone who can hand wire.
I still get paid to hand wire things. And know people who do so, one of whom was who taught me the basics. As far as I know most electricians working in construction wire things by hand. You can get hand wired hifi equipment (where the previously mentioned guy worked), and I've seen hand wired TVs. Amps are simple enough circuits it isn't a super high cost to get it done properly, its just that money put into advertising and endorsers makes for more sales.
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