Peavey White Papers
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Matador
Well-known member
Two articles are missing:
Chapter 8 - How sorry we are for ever producing three-dimensional folded origami PCB's interconnected with breakable wire jumpers
Chapter 9 - How we saved three-tenths of a cent by burying all commonly-replaced parts on the bottoms of PCB's inaccessible to the user
Those folded PCB with machine inserted wire jumpers were very low manufacturing cost (you're welcome). Those machine made jumpers come from a single reel of solid wire on the jumper machine and got cut to length during insertion. Of course solid wire will fatigue and break if you bend it too many times, so don't do that.
The sundry PCBs first get stuffed while together in a single panel, get run through the wave solder machine flat, then get broken apart and folded up to fit inside the SKU after soldering. The wire jumpers don't break during production, but can be broken by repair techs bending them too many time. This technology is far cheaper than the typical multi-conductor or ribbon cable jumpers used between front, back, and/or main PCBs (not only do you avoid the cost of the multi conductor cables, but save the labor needed to insert the cables).
I designed one budget line level mixer using PC mount pots/switches on a flat front panel board, PC mount jacks on a flat rear panel board, and flat PCB routing signals from front to back. I heard that the big boss (actually #2) did not believe that manufacturing cost estimate on the price approval form could be that low and sent it back to cost engineering to recheck before finally approving it (you're welcome).
In the early days of SMD (last century) we mixed pots and switches on the top of a flat budget mixer PCB, with active and passive SMD components on the bottom (solder side) of the PCB, for very low manufacturing costs and affordable SKU pricing (you're welcome).Chapter 9 - How we saved three-tenths of a cent by burying all commonly-replaced parts on the bottoms of PCB's inaccessible to the user
JR
Matador
Well-known member
There is no justification to ever make up for doing it that way, no matter what Hartley told you.
Case in point: here's a pic of me trying to repair someone's beloved Classic 30:
Opinions vary on that. Lower manufacturing cost is powerful when designing value products for price conscious customers.There is no justification to ever make up for doing it that way, no matter what Hartley told you.
Hartley never told me anything about this technology. It was his #2 who didn't believe the low manufacturing cost of my line mixer SKU.
FWIW Back in the good (very) old days the iconic CS power amp series were definitely engineered for repairability with some packaging costs added just to improve serviceability. Near the end of my time there, market competition made such superfluous costs uneconomic. Customers don't care about repair cost at point of sale.
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Back when I was manager over all mixer engineering I used to meet with the service department technicians once every several months and if there was a design flaw that made repairs unusually difficult they would tear me a new one, and they did that more than once, but not about those machine inserted jumpers. They knew their way around the service bench.
JR
PS; IIRC the machine inserted jumper folded PC boards was developed by a guitar amp design engineer for use inside an amp. I saw it and applied it to mixers and/or whatever.
ruffrecords
Well-known member
In the early days of SMD, many parts were not available in SMD and even if they were they were often very expensive. So almost all designs were part SMD , part through hole. Hence though hole on top and SMD on the underside of the PCB.
Cheers
Ian
Case in point: here's a pic of me trying to repair someone's beloved Classic 30:
I chuckled when I saw that, because the Classic 30 was precisely what I'd immediately thought of when I read your earlier post:
The Classic 30 is nice sounding amp, but nightmarish little things to work on, they are. Actually, nightmarish little things they are just to get out of the cabinet in one piece without breaking the jumpers, let alone actually work on.
Bad JR. No dessert for you.
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JR didn't design guitar amps, but I copied the machine inserted jumper, wave soldered flat, then bent up PCB strategy (because I'm frugal). I'm not a guitar amp guy. IIRC the classic series were pretty well respected for their sound, the 30 was probably the smallest and therefore the sharpest pencil design exercise of the entire series.I chuckled when I saw that, because the Classic 30 was precisely what I'd immediately thought of when I read your earlier post:
The Classic 30 is nice sounding amp, but nightmarish little things to work on, they are. Actually, nightmarish little things they are just to get out of the cabinet in one piece without breaking the jumpers, let alone actually work on.
Bad JR. No dessert for you.
Here's a little inside baseball, when they designed the transtube solid state emulation of real tube amps, they mimicked the sound signature of one of the classic amps (was there a 50W?). At the trade show where they introduced the transtube they set up an A/B comparison between the solid state transtube amp and a classic real tube amp.
JR
AnalogPackrat
Well-known member
There was also a Classic 20 model in the series. In 1994 I played a really nice Rickenbacker 1997 ("export" model 330 reissue) through one at Guitar Showcase in SJ. Shoulda bought both!
Any time I open a piece of gear that is made difficult to service I'm thankful that my main amps are classic Fenders.
Any time I open a piece of gear that is made difficult to service I'm thankful that my main amps are classic Fenders.
Thus proving that I am not the guitar amp guy.
I'm confident that it was not made difficult to service on purpose. It was made inexpensive to manufacture and the servicing difficulty was an unintended negative consequence.
At the time my mixer engineers shared a common lab space with the guitar amp engineers and IIRC they struggled with that design. I think they may have even got complaints from the factory building them. I also recall the intense cost cutting pressure we were all working under trying to compete against offshore manufacturing with US built SKUs.
JR
Matador
Well-known member
I'm 90% sure the design was from James Brown, because I recall watching an interview with him on YouTube (I think it might be the Tone Talk podcast...the one with Dave Friedman) where I think James apologized for the design. So I guess all is forgiven. I do understand that repairability 40 years down the road probably wasn't of utmost importance at the time. It is a testament to the tone that people are willing to put up with a nightmarish repair to keep them going.
The last one I worked on I BEGGED the guy to just buy another one, because it was red-plating on one EL84 and that is almost a worst case because the entire chassis needs to be completely gutted to get at the proper bits. However it was the last amp given to him by his (late) father and he didn't care how much the labor cost. To JR's point: the customer is always right, even when they are wrong.
AnalogPackrat
Well-known member
Yes, but Fenders were made easy to service because Leo started out in the radio repair business and grokked that factor. Design for serviceability does not have to be uber expensive, but it should be considered more often than it is. But with MBAs and bean counters running everything...here we are.
and Peavey's were engineered to be easy to service too, back when. That calculus fell apart when several manufacturers moved production offshore (or to Mexico) making it impossible to compete heads up building gear in US factories. I have known a handful of people who worked at Fender either before or after Peavey gigs.
Coincidentally Fender's Principal Design Engineer now is James Brown well known for his work while at Peavey with Eddie Van Halen on the iconic 5150 guitar amps. Without sharing too much inside information James recently sold off his successful Amptweaker pedal company and joined Fender.
Coincidentally for this thread, I expect James' fingerprints are all over that contentious Classic 30 folded PCB design.
JR
Matador
Well-known member
To be fair Fenders were also made for a price point with the cheapest materials that could be found: wax impregnated cardboard with brass eyelets from jeans wasn't exactly the best way to make something that survived the ages, but it sure was cheap. . Especially now, when the boards leak voltage everywhere after absorbing 60 years of moisture and cigarette smoke and becoming conductive.
The ultimate for repairability (IMHO) is a 3" strip of 1/8" (125mil) Garolite XX (paper-reinforced phenolic resin sheet) with Marshall-style swaged turrets. Anytime I need to restore a 60's Fender this is what I use. It's rated at 40kV dielectric breakdown voltage, and has a bulk impedance of 10MEG / mil and doesn't absorb moisture, and tolerates being soldered without deforming (so long as you down leave the iron on the turret all day). PTFE sheets also work really well for this.
. Especially now, when the boards leak voltage everywhere after absorbing 60 years of moisture and cigarette smoke and becoming conductive.The ultimate for repairability (IMHO) is a 3" strip of 1/8" (125mil) Garolite XX (paper-reinforced phenolic resin sheet) with Marshall-style swaged turrets. Anytime I need to restore a 60's Fender this is what I use. It's rated at 40kV dielectric breakdown voltage, and has a bulk impedance of 10MEG / mil and doesn't absorb moisture, and tolerates being soldered without deforming (so long as you down leave the iron on the turret all day). PTFE sheets also work really well for this.
AnalogPackrat
Well-known member
Cheap and repairable.
I hear those stories, but haven't had any trouble with the waxed eyelet boards in my three silver faces that are pushing 50 years. I got them second hand (or more) and they've lived indoors with climate control since then ('91, '95, and '08). Maybe the problems come from storage in garages, basements, sheds, etc.wax impregnated cardboard with brass eyelets from jeans wasn't exactly the best way to make something that survived the ages, but it sure was cheap.
Can't argue with that. If I ever get around to it, I want to gut my red knob Champ-12 and build something better in the chassis. I'll use fiberglass or phenolic tagboard or turretboard.
