vintageHIWATTconvention.com

Hey guys so I'm having a little issue with my 79 DR103 (the one in this thread... LINK). Since I got it, I never thought it was as loud as it should be. Now that I have a 74 DR504 I can say with confidence that the 50watter is definitely louder! A friend of mine has recently de-modded the Canadian Distributer mod, changed the preamp back to early 70's stock, and replaced the filter caps (thanks VHR!). It definitely sounds the best it has since I got it but it is still not as loud as it should be... we are stumped as to why! When I bought it the guy told me it didn't work and that some tech told him the OT was blown. But... it did work. I figured they didn't understand the CDM (Canadian Distributer mod) and must of plugged into the bright channel with the normal channel all the way down. When you do this you don't get any sound because of the nature of the CDM being like a JCM800 cascading the input channels, so the normal channel volume needs to be up for you to have any sound from the bright channel. Now if the OT was blown there would be no sound from the amp right? FYI the power tubes in there right now are a quad of Winged=C= EL34's. I don't know were to go from here, I like the tone, but it's not as loud and clean as it should be. Any suggestions on things to try or look at to get it up to speed?

If you're comfortable poking around inside a live amp, you might want to check the voltages and compare them to the 1980 DR103 on this chart:
http://members.shaw.ca/house-of-jim/Html/Hiwatt.html

Any large discrepancies might help you pinpoint the problem(s).

Actually that's my buddy's site! I'll have to ask him if he tried that.

You could always wait until the weekend of the 27th... I hear there might be a guy in attendance that knows a couple of things.

Ya Clayton's been bugging me to bring it down there. I'm trying to travel light but I might bring it along.

Have you tried a different quad of output tubes? Are they all lighting up?

Are you sure the impedence selector is properly set (and that there's no oxidation on the contacts)?

Those would be a couple of easy things to check.

Dave

I have tried a different set of output tubes, same thing, lower than expected volume and they all light up. I've also tried a bunch of cabs at 4,8, and 16 ohms too. It's a mystery...

Just bring it down to Indiana.

--mark

Will do!