Hiwatt DR-103

[manray]

Hello,
I'm new to the site and I need some help. I just purchased a 1979 Hiwatt DR-103 that is bone stock except for replacement tubes. It sounds great but never hearing one in person I was wondering if it could sound better. I called a reputable tech in the Atl. area and he said it would need new caps and a bias pot installed but I am leary of adding anything to this head.
I would appreciate any advice in this matter.
Thanks, Manray

 

[stu42]

It depends on what you mean by "better". What are you looking for in terms of sound?

A lot of old Hiwatts appear to be stock but they often are modified so the normal channel cascades into the Brilliant channel - to stack the gain. This can be done without changing the exterior look of the amp and it works really well so, unless you're familiar with the operation of a stock amp compared to the modded amp, you may not be aware of it.

I know that the old Hiwatts often don't provide enough bias voltage to work properly with newer tubes. I don't know all the technical details but an excellent amp builder/tech (James Peters) I know told me this - it's not really a secret. He installed a bias pot and set it up so it would provide the necessary voltage and that can be done fairly simply There are a couple of ways to do it from my understanding but I don't know enough to describe them. Also, it's true that the can caps could be leaking or dried out as well. I know that once James was done with my amps they sounded considerably better than they ever had (I've owned three DR-103s and one DR-504).

In general, it would be a good idea to have it checked over by a good tech. It may improve the tone a lot. Simply making sure the tubes are biased properly could do a lot of good for the tone. This is a much under-rated necessity.

The nice thing about those heads is that, being hand wired - and extremely nicely at that - any mods that don't involve drilling holes or doing anything radical can be un-done fairly easily by a later tech. A good tech will make sure they maintain the vintage aspects of the amp while, at the same time, making sure it works properly with contemporary tubes.

 

[doctord02]

While the tech you called might be right, I'd be leary of anyone that knew what it needed without laying eyes on it or hearing for them selves. That said, a cap job and correct biasing *is* pretty much the standard thing to do with a vintage amp.

 

[manray]

It sounds good if the normal and bright volumes are below 12:00. Also, the master volume seems to be at 100% at about the 9:00 setting with no more apparent loudness the higher it gets, but only on the normal channel.
I tried the normal and bright volumes together and there seems to be no cascading effect.

 

[stu42]

While the tech you called might be right, I'd be leary of anyone that knew what it needed without laying eyes on it or hearing for them selves. That said, a cap job and correct biasing *is* pretty much the standard thing to do with a vintage amp.

Yeah...I was thinking the same thing (though I didn't say it). Good point.

 

[stu42]

It sounds good if the normal and bright volumes are below 12:00. Also, the master volume seems to be at 100% at about the 9:00 setting with no more apparent loudness the higher it gets, but only on the normal channel.
I tried the normal and bright volumes together and there seems to be no cascading effect.

That doesn't sound right to me. That amp should continue to get louder and louder as you turn it up. Granted, in my experience, once you turn it past about 2:00 on the master volume dial my amps never really got louder. At that point, they just got more and more saturated, thicker and higher-gain sounding. And...your amp should be insanely loud when it's cranked.

I'd get it checked if I were you.