Handwired vs machine made

rico

Someone asked me this the other day and I couldn’t really come up with the answer that didn’t sound like waffle. 

What would you say the main reason for an amp to be hand wired rather than pcb/machine made is?

SunDevil

To kick this one off...

1) Repairability 
2) Space between components for cooling and to reduce interference 
3) Not having all electrical signals in parallel lines is meant to reduce cross-over noise

ICBM

Easier repairability, and the often higher quality of individual components - they're often larger and more robust - are about the only ones.

But if you want to it's actually possible to make a PCB amp with both these things - some companies do, even if most choose to go the other way and minimise cost.

Other than that it's largely snobbery.

hywelg

ICBM said:

Other than that it's largely snobbery.

Not entirely. Aesthetics play a part too. Theres nothing quite as pleasing as something made with obvious care and attention to detail. Hiwatts for example. 

guitarfishbay

hywelg said:

ICBM said:

Other than that it's largely snobbery.

Not entirely. Aesthetics play a part too. Theres nothing quite as pleasing as something made with obvious care and attention to detail. Hiwatts for example. 

But in use you can’t see how an amp is wired.

martinw

All the above, plus some less tangible things, like maintaining the skills necessary to do that kind of thing which then adds to the pool of people who can also repair things down the line.

Supporting local business, producing less landfill, maintaining a skills base of technicians who can repair things, resulting in less environmental impact, societal and economic benefits. Life would generally be better if we all owned fewer, better quality things and valued them more.

There's a lot to be said for having a relationship with the person who made your amp (or whatever it is) in that you can often tailor things to suit your preferences when things are made in small volumes. Then there's pride of ownership from having something unique, or nearly so.

The amps themselves are often better sounding. Not always, and as ICBM says, a good PCB can be just as good. However, most manufacturers change the design to the limits imposed by PCB, rather than copying the handwired layout. This compromises component and audio quality IMO. The first Marshall PCBs were direct copies of the turret board layout, with the same components; sounded great and easily repairable ad infinitum. Now they're all squeezed into a much smaller area with a load of SM switching and soon-to-be obsolete ICs in the rest of it.

That's my take. It's not for everyone, and there are some obvious disadvantages. It's nice to have the option!

Gadget

^ Wisd

ecc83

"Easy repairabilty" I would question a bit. If the PCB is of good quality (and the tech has a modicum of skill)

Then there is no contest in fact it is more difficult to leave 'boutique' and pretty amp looking untouched than a good PCB jobbie*. 

From the SONIC point of view again, nowt in it IMHO except that a PCB design will be more consistent sample to sample.  The biggest argument for PCB (but not SMT but we have to be realistic if we want  all the bells and whistles at sensible prices**) is the cost. Said it before but I do wish a certain mnfctr of my acquaintance would make a version of their turret wired amps in a GOOD quality PCB design with a sstate rect, therefore cheaper PT.

*If you have to replace a PT e.g. (and anything can go buzzy!) and it is laced in 'Wireman' style, your only option really is to chop and splice the wires, shrink  sleeve and hide the work!

**I think there should be a law! All SMT kit should be available as a 'Service Replacement' to bona fide techs.

Dave.

ecc83

Er? "Crossover noise"? Do you mean 'Crosstalk'? If so not possible in a mono amp and would be so far under noise, not a bother in stereo either.

Parallel wiring could cause coupling. Either noise, heater hum say. or instability and squegging. Can get that with badly designed PCBs of course. 

But! I do agree with MJW in that we need to maintain skills and repair MUCH more stuff, not just amps, because we shall soon need another fucking planet!

Dave.

ICBM

hywelg said:

ICBM said:

Other than that it's largely snobbery.

Not entirely. Aesthetics play a part too. Theres nothing quite as pleasing as something made with obvious care and attention to detail. Hiwatts for example. 

I would say a really nicely made PCB is more of a work of art... in fact legally, it is one - you can copyright a PCB layout, but not a circuit.

You can make a PCB amp with obvious care and attention to detail as well - look inside a Mesa for example.

Collings

One consideration for the manufacturer is their target buyer. If they are competing in the "boutique" high end of the market there is an expectation from most of the potential buyers the amp will be "handwired" , "no PCB's" etc but as stated by many above that is no guarantee of a great sounding and reliable amp but unfortunately many buyers looking at this end of the market have the "PCB bad", "handwired good" mentality. 

Danny1969

If we are talking about Valve amps then there's generally not a lot of automated tape reel SM PCB involved as the voltage levels are too high for the flash over of SM components, you can use it for signal processing and routing though and in these areas nothing basically should go wrong unless it's badly designed. The things that generally cause failure, such as high currents, heat, moving vibrating components don't apply here. Consider your phone and the abuse the motherboard can withstand in terms of shock and vibration, underfilled BGA SM design is actually far more robust than conventional through hole design. 
As someone who has to fix SM stuff (because outside of guitar amps everything is SM) I would say it is a pain in the arse but once you work out a few techniques and get some appropriate tools it's not too bad. As time moves on repairers will have done SM repairs from the start and won't be familiar with through hole stuff maybe and certainly not valves. 

I don't have much experience in making valve amps but I imagine there aren't machines that can bolt on a transformer and wire it, or valve bases etc .... that must still be done by hand ?

stickyfiddle

Don't forget warm fuzzies. Every handwired Badcat comes with a lovely warm fuzzy feeling that you don't get with the PCB ones. 

Telejester

ICBM said:

hywelg said:

ICBM said:

Other than that it's largely snobbery.

Not entirely. Aesthetics play a part too. Theres nothing quite as pleasing as something made with obvious care and attention to detail. Hiwatts for example. 

I would say a really nicely made PCB is more of a work of art... in fact legally, it is one - you can copyright a PCB layout, but not a circuit.

You can make a PCB amp with obvious care and attention to detail as well - look inside a Mesa for example.

For beauty, quality and care taken in a pcb design and layout i say Hiwatt....end of story.

For a rubbish collection in a box, look nside a marshall dsl.

ICBM

Telejester said:

For beauty, quality and care taken in a pcb design and layout i say Hiwatt....end of story.

I assume you don't mean PCB .

I know this will cause howls of protest, but actually a Hiwatt is not the be all and end all, even of handwired amps. The laying out of everything in neat straight lines with the wires all bunched together is actually *bad* practice if you're concerned about minimising crosstalk and stray capacitance, which is one of the common criticisms of PCBs. A Hiwatt layout duplicates that to quite a large extent. It *is* consistent - it's notable that Hiwatts vary less from one example to another than Marshalls for example - but as Dave said, that's one of the prime advantages of PCB.

It's also worth mentioning that all reliability-critical, cost-no-object electronic systems in use now such as military, avionics and medical equipment use PCBs.

Telejester said:

For a rubbish collection in a box, look nside a marshall dsl.

True, but that's largely due to the low quality components, jumper connectors with flimsy ribbon cable etc.

Look inside a Jet City - a far cheaper amp - and you will see, if not quite a thing of beauty, certainly none of those problems.

SunDevil

I used to work for one of the Digital TV companies and at one point, the failure rate of new Set Top boxes coming off of the production line was at 60%.

Said company were happy to work on the cheap, were largely happy to accept the high failure rates and employ lots of labour in the Far East to fix the failures before sending them on.

The point I'm trying to make is that if you are building amps based on PCB so that they can be mass produced in a part of the world with cheaper labour, are you testing each and every amp before you ship them? ..probably no more than a small % are tested.

There's no reason why you can't up the price point on a PCB design to get great quality, but that's not what a lot of companies are using this for.

Handmade amps put together in small numbers are more likely to be tested / soaked before they are sold and early failure less acceptable to the manufacturer / builder.

I know an amp builder in the US who drops every one of his amps from about 2 feet onto a table whilst they are up and running, to ensure that there are no issues or even an interruption / disturbance in sound - unlikely to get that when items ship by the container load!

JayGee

rico said:

Someone asked me this the other day and I couldn’t really come up with the answer that didn’t sound like waffle. 

What would you say the main reason for an amp to be hand wired rather than pcb/machine made is?

Production numbers.

If you’re building one-offs, by the half-dozen or so, and/or offering a high degree of customisation then the cost of designing PCBs, having them made, and programming a machine to populate the boards is going to be a lot higher than working out a turret/tag board layout and putting it together by hand (and that’s before you start considering multiple iterations of tweaking to get it just right).

That and being able to justify absurdly high prices to cork sniffers...

ecc83

"laying out of everything in neat straight lines with the wires all bunched together is actually *bad* practice if you're concerned about minimising crosstalk and stray capacitance,"

Depends on what you bunch IC! Wires carrying DC, don't matter. Wires carrying AC matter since keeping them tight minimizes stray fields. If you look inside a Quad ll or even the solid state 303, works of art because the guys knew what they were doing. In any case every feedback amp will need a 'pole' cap somewhere so it makes sense to have V tidy wiring so that the capacitances are consistent.

Of course, if someone is daft enough to run OT anode wires across an input? WHEeeeeee! 

At RF you have to go very 'point to point' . I have only very rarely changed a transistor in a UHF tuner and had the gain as good as it was before and that matters in Northampton because we get ***t reception from everywhere!

And! You would THINK a p2p amp and would HAVE to be tested? How then did an A100 get to me with a 220mfd 500V cap in the wrong way round! (yes, a bloody mess)

Dave.

rico

ICBM said:

Easier repairability, and the often higher quality of individual components - they're often larger and more robust - are about the only ones.

...

Other than that it's largely snobbery.

Snobbery is basically what I said. 

DJH83004

There is an additional dimension to this discussion around the concept of handwired, these are a couple of amps that I have repaired / serviced in the past, one turret board, one true P-to-P using tag strip. Both well respected builders with great reputation for tone and quality. One amp is a dream to work on the other is a nightmare! But hey-ho you don't buy amps for the benefit of the amp tech     

RaymondLin

Handmade sound more posh.