Kenny's Hiwatt pics (tecky stuff only)

[Highlander]

EDITORS NOTE... I lifted this from where Chris found me back in February, so this is just for the curious...

I've just added her to Mark Huss' database (back in February) and after some discussions with him he has decided to call her a "DR103 SWITCH" as the plate identifies her as that, not an AP, or an SAP. she looks like a DR103S (similar to the '74 on Mark's site)...



"SWITCH"...? She is not identified as an AP or an SAP or as a DR103S (see pic of plate) and does not follow the Gilmour type of layout but is much more similar to the '74 DR103S on Mark's site - is there anyone else out there with a brother/sister to her that can give me an idea of how many others there are...?


The view from the front row - has anyone ever tried to remove Mr Reeves' glue...?

and the internals...

And now for the "VALVE-HEADS" department...


centre stage, so you can get the jigsaw right...


tag-board overview...

and "I'm ready for my close-up now, Mr DeMille..."

























Stop drooling, it's most unbecoming...

[Dave W]

That is drool-worthy. A bygone era.

[Highlander]

Dave... Mark Huss advised me to replace the main capacitors (which are dated 1969), but the sound is soooo good... I even have some Mullards for the pre-amp stages which I keep meaning to fit - the present set came out of an even older Marshall; I'd be curious to try a brand-new set, just to see (hear) what the sound would be like...

[Dave W]

I understand... you don't want to risk possibly losing the sound by replacing them. But they don't last forever, sooner or later you will have to.

[Pilgrim]

I sincerely doubt that replacing a good quality cap with another good quality cap will affect the sound.  All they do is store juice for demand.  If I had any doubts about their remaining service life, they'd be out in a heartbeat.  I didn't think twice about updating the caps in my 1967 BF Bassman.  Much better than smoking the amp!

[chromium]

Dave... Mark Huss advised me to replace the main capacitors (which are dated 1969), but the sound is soooo good...

Replacing the power supply filter caps shouldn't adversely affect the sound.  This will just ensure that clean power is making its way to the other components, reducing the chance of their failure and unwanted noise/hum.  Electrolytic caps (the ones in the metal cans) chemically break down with time, and power supply filter caps can really take a beating with spikes on the AC power line and such.  The caps in the signal path that materially impact the sound - tone caps, etc... - are not as critical to service.  I've been trying to work my way through preemptively replacing power supply caps on some of my old gear - keyboards, just did my space echo...   Haven't done any high voltage stuff like that yet, though.  Be careful in there!  

Great photos!

[Dave W]

Shouldn't... but sometimes it's perceived as a difference.

[Basvarken]

Impressive pics Kenny!

[Highlander]

Al and Joe... understood and willing to take the plunge...

Joe... 34 years of sparkying, 21  of those on regular voltages put up to 100 amps per phase on the bigger "flight" dishwashers (boring) but they sure went with a BANG when they did blow, and not vain enough to not be willing to take advice... 

As you command...

Rob... had to get the pics "just so" for the teckies over on the Plexi site when I first went "live", oh-so-long-ago... Mark Huss was most helpful and I assured him I'd give him "first refusal" if I ever "lost my marbles"... 

and Dave... Perception... such a mighty thing... weird, considering my attitude to my instruments... 

[Pilgrim]

Shouldn't... but sometimes it's perceived as a difference.

The psycho-acoustics are always a factor.  If we want something to sound "different" or "better" or "worse", chances are that we will perceive it that way - regardless of actual performance.

[Highlander]

Oh so true...

[Chris P.]

Nice! And yeah, bringing you hear will haunt me for the rest of my life!

[Highlander]

You just don't know what you unleashed, Chris... 

Good luck with the projects and looking forward to when you can dip in again...

[Highlander]

Yes, this thread is old but it remains a warning for that expression... the road to hell, etc...

I went to a rehearsal with a guitarist I worked with a while back that was trying out a drummer and a vocalist and needed someone he knew could just "slot in" and I thought it would be nice to take the beastie out for a workout...

Yes, half hour in she just faded out and stopped working...

I'm sure this is the power caps - curiously enough I have had the pages saved for the spares (easier to buy a "kit" of all the required caps on "your" side of the pond than here, 4 miles from where my amp was born in DR's garage... anyway, hopefully I can report a repair here a bit sooner that the rebuids on my RD and my Demetriou...

[Psycho Bass Guy]

That sounds more like you've lost a cathode resistor somewhere in the preamp. Filter caps going south would give you major hum followed by blowing your main fuse, no puns intended.