Amp recommendations

@z32kerber,
The 300b is a marvelous output tube in either SET,PSET or push pull mode if well implemented in an amplifier design and build. You’ve been happy with your amplifier and speaker pairing 23 years, that speaks volumes for certain.

After such a long time of satisfaction ("loved the sound") what makes you believe or suspect that you need a higher power amplifier? 25 watts of push pull 300b is not meager IMO. It would be interesting if you’re curious enough to compare to higher power amplifiers using KT 150, KT 88, el 34 , 6550 etc.

You may or may not prefer these indirectly heated Pentode type tubes to your DHT type 300b. Some here have also suggested solid state amplifier alternatives. I’m very partial to 300b and other DHT tubes (Just so beautiful sounding with my beloved jazz in particular 😊). But of course personal taste varies greatly amongst us all. I have no doubt that you’ll get things sorted out one way or the other. BTW what tube type were used  in your 40 watt Cary amplifier? Are you considering 75-100 watt power range?
Best of luck,
Charles

You might take a look at Don Sachs’ KT88 amp.  Best of luck. 

@charles1dad 
thank you again for your fantastic insight. The 40 watt mono blocks I had were Cary 40Ms. They used EL-34 tubes. My preference in music is like yours - jazz.  
Some history. In 2017 I did some retubing. I replaced the Cetron 300Bs with Genalex Gold Lions. In late 2018, I was having some issues with the amp and took it to a recommended shop here in the Portland Oregon area to have it checked out. He found that the rectifier tubes needed replacing and replaced them with JJ 5U4GBs. He also found come caps that were bad. He bench tested it and set the bias. I had been busy with projects and other things for the last couple of months and hadn’t listened to my system. Last week I went to power it up. I always let things warm up before playing any music. When I went back 15 minutes later to play something I noticed only 1 of the the 300Bs was glowing and not that much. The others were stone cold and the 1 that was glowing wasn’t that warm. One thing that I noticed was that when I powered it down, the “plate voltage” light stayed on for a long time. When things were fine, the light would go away after a minute or so when powering down. Not sure if this has anything to do with my situation.
I wasn’t overly satisfied with the shop I took my amp to in 2018. He’s a one man shop and super busy. It took him 2 months before he actually looked at my amp. Then it was only a couple of days before it was done. It felt to me like he rushed through my job. So my plan is to try and find another shop nearby (might have to go to Seattle or possibly ship it somewhere), that can figure this out and get it repaired. 

@z32kerber,
Well given that story it does seem quite possibly that the Portland repair tech was overwhelmed with work and not as thorough as he might have been. I do get the sense that there’s a straightforward solution to getting your amplifier fixed. Your stated plan to address this is on the mark.

You’ve had the Cary-Chapman pairing for 23 years of listening enjoyment. During this period did you ever feel as though you were lacking amplifier power or was that concern generated by some of the replies on this thread?

As a number of people here have written there are definitely good options available given your budget range. It could prove to be informative to hear other  amplifier topologies. I believe that your Cary 300b is formidable and not easily surpassed on sonic quality. As you certainly know the 300b can sure reproduce music in a very organic manner.
Charles

I would start by calling Cary Audio.  I think you will find they know their products very well and will be more than happy to work with you.  You might also try reaching out to Dennis Had directly.  He is no longer associated with Cary Audio but started the company, was the designer of your amp and I believe will be more that willing to render an opinion on best way forward.