98RT......need some help!!!

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Hi....New guy here...

I have an old 98RT that has been in my dad's garage for years(15+). It was originally mine but it quit working and I just stored it and forgot about it. Back then I was into hard rock and (early)Alt rock and didn't appreciate what this amp is. Now I do. Here's the deal.....#1: it has a sticker inside that says '98RT 568' ...that's all I can find. Any way to date this thing? #2 all the tubes light up and you can hear the tremelo pulsing but no sound....anyone have any insight as to what may be wrong? I plan to take it to a tech to be cleaned up-restored. Are there any issues that anyone has run across with this? ie tubes/parts no longer available....and can it be reved up to a bigger output....i believe they are 15 watters but could be wrong. I play blues, country and roots rock type stuff these days and would really love to have this baby back in commision.

Any help or advice will be deeply appreciated...

Slim
 

dapmdave

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Welcome to LTG, slim.

I'm not an amp expert, but we do have a few very knowledgeable folks here that will likely pop in pretty soon to give you lots of good info and help.

Dave :D
 

capnjuan

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Hi Slim; welcome to LTG and congratulations on re-discovering your 98RT.

Date: not much reliable information around ... but it's probably in the '61-'64 ballpark ... plus or minus ... sort of ...

No sound: too many things to guess but your amp has electrolytic capacitors that dry-out over long periods of no use. Unless they can be proven good, replacing them is usually the first step in an overhaul.

Tubes/Parts: just about everything necessary to make that amp run like new is available somewhere in the aftermarket.

Bigger output: Power out is mostly a function of the power transformer. Most 6V6 amps are nominally rated at 15 watts but if you want to increase it's rating, you'd have to change the power transformer, output tubes, output transformer, and redesign the bias. If the amp is in fair condition, you could do you chances of selling it one day more harm than good by re-engineering it.

Despite their charm, there isn't a great deal of interest in 98RTs in original working condition and there will be less interest in one that's been messed with. You might think about getting it in good running condition and, if it still doesn't give you want you want, sell / trade it for something closer to the mark.

Good luck with your new (old) amp!
 
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Thanks for the advice....I think I'll have it restored to original specs and then mic it up and put it through the PA.

Glad this sight is here!!!

Thanks again
 

capnjuan

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Hi Slim; if you or your tech needs a schematic; our member Emperor-TK has put one up on the web: see link in this thread. If/when you get it running, you can get some tone variation by switching 6V6s in and out; older brown base / smoked glass '50s tubes will put out a darker, meatier, more compressed tone. The newer 6V6s particularly JJs will run at nearly 500V ... way more than you will have in your power supply ... but the JJs are purpose-built to sound a little more like 6L6s; cleaner, brighter, a little tinklier.

I don't know whether the 98RT lasted long enough in the product line to get done over with 12A_7s instead of the 6__7s in the schematic. The 6__7s do the same thing as 12A_7s but have octal bases ... no drop-in substitutes but there are lots of 6__7s available as NOS and are pretty cheap. The bad news is that, statistically, you might be more likely to find a clunker or two in whatever you buy but the good news is that they are pretty cheap which will allow you to buy / test / discard until you find several that hit you just right.

Finally and if you get a chance, take and post a few pics; outside and chassis interior; (directions for posting pics here if you need them). Good luck and best wishes; John
 
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