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Cover plate and caps

Posted: Wed Sep 02, 2009 2:43 am
by steve
I'm working on a newly acquired '73 DR103 and I hope someone with one of these can provide some info for me.

With the chassis removed from the cabinet, there is a large rectangular piece of sheet metal that is currently held in place with electrical tape to cover the chassis components. When the chassis is slid into the cabinet, the plate sits between the bottom of the cabinet and the chassis. Did the original Hiwatt's use this plate? How was the plate attached originally? I don't have anything to compare to and cannot find a picture online. It seems it should be glued somehow to the bottom part of the cabinet so the chassis just slides over it, but I don't think this was ever glued :?

Also, the DR103 has a 16+16 cap, and I noticed my SA112 has a 16+32 cap. VHR's standard cap kit has the 32+32 cap. Is the 32+32 an appropriate replacement because it can filter better than the original 16+16 or 16+32? Or is it better to recap with the same cap values?

I know these questions sound a bit basic, but I'd appreciate some input.

Thanks all.

Re: Cover plate and caps

Posted: Wed Sep 02, 2009 3:26 am
by OldSchoolDave
Steve,

The plate is there to shield the circuitry from radio interference. It may have had a "scribble" of glue originally to hold it down but, usually, it's just the chassis bolts that keep it in place. Doesn't have to be a perfectly sealed / secured joint.

I'll let others speak to the caps, though I do know that VHR stocks a couple of varieties for those who want to match original values as closely as possible.

Dave

Re: Cover plate and caps

Posted: Wed Sep 02, 2009 12:07 pm
by Dr.HI-TONE
The 32+32, 16+32 and 16+16 are completely interchangeable. I doubt anyone can tell the difference by listening to an amp that has one value vs. another. As far as amp performance is concerened, I have not noticed much if any difference between the different values.

We started offering the lower values so that people could “drop in” the exact value as what was installed originally. Some of us are more sticklers for accuracy than others.

Re: Cover plate and caps

Posted: Wed Sep 02, 2009 12:22 pm
by mhuss
OldSchoolDave wrote:The plate is there to shield the circuitry from radio interference. It may have had a "scribble" of glue originally to hold it down but, usually, it's just the chassis bolts that keep it in place. Doesn't have to be a perfectly sealed / secured joint.
+1
Dr.HIWATT wrote:The 32+32, 16+32 and 16+16 are completely interchangeable. I doubt anyone can tell the difference by listening to an amp that has one value vs. another.
+1, even dog ears will never hear the difference in a double-blind test. With typical electrolytic cap tolerances of +40/-20%, a "16" and a "32" could be *really* close in value and still be in spec. From a technical point of view, bigger is better (up to a point), as this will reduce hum.
Dr.HIWATT wrote:Some of us are more sticklers for accuracy than others.
"Sticklers for accuracy" -- is that the P.C. term nowadays? :lol: :lol: :lol:

--mark

Re: Cover plate and caps

Posted: Wed Sep 02, 2009 12:26 pm
by Dr.HI-TONE
:lol:
it sounded better than "extremely anal retentive" or EAR, which I seem to recall you referring to me as such....... :lol:

I can't help it!!!!

Re: Cover plate and caps

Posted: Wed Sep 02, 2009 12:30 pm
by mhuss
Dr.HIWATT wrote::lol:
it sounded better than "extremely anal retentive" or EAR, which I seem to recall you referring to me as such....... :lol:
I never!! Well, I don't remember saying "extremely" anyway. :lol:

--mark

Re: Cover plate and caps

Posted: Wed Sep 02, 2009 12:33 pm
by Dr.HI-TONE
well, if the shoe fits........... :lol:

Re: Cover plate and caps

Posted: Wed Sep 02, 2009 4:41 pm
by steve
Thanks for all the help!