Post by soupdragonPost by Dave CurtisPost by RichLPost by RichLPost by soupdragonWhy? A well designed printed wiring board amp is a match for
any handwired amp and it is consistent. (Key is 'well designed',
of course)
Much more difficult generally (and therefore more expensive) to
service.
Servicing a valve amp simply involves changing the valves as
neccessary. I don't see how that can be more expensive than dealing
with a hand wired one. Also PCB (well designed ones) can be very
reliable and robust - much more so than hand wired equipment - as it
can give better mechanical support to componnents than tag/turret
board.
OK, how long does it take to change two jacks and three pots attached
to the circuit board of a '96 Valvestate?
I did say (twice) a *well designed* PCB.
You did, and you're correct. Too bad they don't design them very well
(anymore). Name one current manufacture amplifier with a
"well-designed" circuit board that isn't a pain to service.
Post by soupdragonA Valvestate hardly qualifies
for that on any criteria! But..chassis out probably 5 -10 minutes if
I have my tools to hand.
Dream on... I know better.
Post by soupdragonPost by Dave CurtisNow, how long to change two
jacks and three pots in a '72 Fender Twin Reverb?
Is it a 4 channel amp like the Marshall?
Where did "4 channel" come from?
Post by soupdragonOtherwise it's apples and
oranges. Show me a 4 channel hand wired tube amp for a true comparison
and I doubt you'd be able to do it in twice that time due to the
restrictions the tie wrapped wiring looms you'd have to move out the
way to get access to the components would put on you.
There's no "tie wrapped wiring looms" in a '72 TR.
Post by soupdragonPost by Dave CurtisWhat's that? You
don't need to change them because they were never mounted on the
circuit board and therefore never subjected to undue stress?
Umm..mounting sockets on PCBs has always been a no no - its bad designs
and fails the criteria.
And yet they keep doing it.
Post by soupdragonANyway, pots do fail largely due to moisture
ingress.
No, worn carbon tracks used to be the most common failure mode. Now I
see more pots broken from the stress from being attached to a
faceplate *and* a PCB.
Post by soupdragonOh, and I have a Vortexion 50 watt (2 x EL34s) from 1958. It has
a PCB and has never had to have either jacks or pots replaced and still
works. *Proper* design means you don't have component failure and
mechanical stresses are taken into account. WHy hasn't this amp failed?
Because it was mil spec and used for PA systems on Royal Navy warships.
That meant it had to be tough and that meant well designed printed
wiring, rather than p-p wiring with the inherant strain on solder joints
that the weight of cable harnesses would cause.
My 57 Stromberg Carlson and my mid 40s Webster PA amps were handwired
and both are still going strong. They're both well-designed also.
Post by soupdragonPost by Dave Curtisthat's what I thought.
What did you think?
I'm thinking you've never been in either a Valvestate or a Twin
Reverb.
Post by soupdragonPost by Dave CurtisValves aren't the only things that fail,
especially in a PCB amp. Been there, done that. PCB amps (tube or SS)
are usually much more time-consuming to fix than point-to-point.
So how long do you think it'll take you to repair that 4 channel p-p
wired valve amp, hmmm. Get back to me when you've figured that out.
I don't think, I *know* it takes longer than it does on the Twin. I
also know that I've done it way more often on these newer amps than on
older ones like a Twin.
Post by soupdragonPost by Dave CurtisTry
replacing a preamp socket in a PV 5150 and get back to me on that.
Bring it on. 8 to 10 minutes.
Bullshit. Those sockets are soldered onto one side of a 4-sided
rectangular box of a PCB. It would take 8-10 minutes just to pull the
chassis and label all the ribbon cables. Wanna see?
Loading Image...Loading Image...Loading Image...Post by soupdragonTry changing the jack socket on an
early Sound City AP120.
What's that? You can't because some dingbat
at Sound City when designing the amp put the first valve socket too
close to the jack socket and you had to remove the valve socket first
(and, of course, the p-p leads to the socket were way too short so you
had to desolder the whole socket first) before you can get the jack
socket out? Of course, during production, that wasn't a problen as they
simply popped the jack socket in before the valve base and wiring up.
Well, I didn't have to go through all that trouble...
Post by soupdragonBad design is commonplace
Especially the newer stuff.
Post by soupdragonand p-p is not exempt.
Personally, I see a *lot* more badly designed PCB amps than p-p, but
then again, I fix broken amps.
Post by soupdragonRather than accepting
bad design, you should be demanding much higher quality standards.
Yeah, right.
Post by soupdragonAlas
musical instrument amplifiers seems to the last remaining bastion of
poorly designed equipment.
Actually, MI amps were the last holdout against the downward spiral of
designed obsolesence. Why have it fixed when you can get a newer one
cheaper? Who gets their TV fixed anymore?
Post by soupdragonBTW Ever tried to repair a p-p wired colour TV? I have - give me PCBs
any day.
Don't do TVs, thanks. I've got a full plate as it is. I have a
Magnavox w/ a intermittant on the PCB; do *you* want a crack at it?.
I'm thinking I'll just get a new one.
I agree that a well-designed PCB amp can work as well as a
well-designed P-P amp. It's just that most of the new stuff is crap
that keeps getting more tech unfriendly; I won't work on some of it.
We all have our opinions, and mine is that it's easier to replace a
component in a handwired "p-p" amp than it is to pull a circuit board
and replace a component, that's all.
Do you disagree that PCB amps are "Much more difficult generally (and
therefore more expensive) to service"?
He *did* say generally. Ampeg V-series amps are a breeze to work on
because you don't have to pull a PCB, just a coverplate.
Back to the topic amp; I'm not sure about the Mesa Boogie Express
5:25 in particular, but Mesas used to have flying leads on their pots
& jacks. I have fixed a few unsupported large components on some Mesa
boards, but i'm sure glad I didn't have to pull them out to do it.
-DC