Need Some Educated Advice...For a Newbie Tuber

I have the same amp (JD1000A) that also had stock tubes. I gave Jim MCShane an email and he set me up with some input/driver tubes based on what I told him I was looking for. 4 tubes for < $100. The difference was surprising to me, well worth the money.
Also - I have my amp on the bottom shelf (effectively on the floor) and as Tobias said, this made a difference for me. But the other position is on the top shelf of a not-very-stable rack.
Regarding the Jolida - I think it's a fine amp. Plenty of power to drive Martin Logan Ascents, sound is very good especially with the NOS tubes.

hi, I suspect what you are hearing is lack of power with your tubes, lack of power or clipping the amp almost always sounds exactly what you are discribing. you should check the impedence curve of your speakers, they might suck up lots of power. if so you need a higher power tube amp. if you can afford it try a rogue audio m150 monoblocks, they put out 150 wpc and can drive most speakers out there. another thing to try is bi amping with the tubes on the tweeter mids, and your adcom on the bass, if the problem is lack of power , no feet or nos tubes are going to help, good luck , chrissain

I did a quick check and there seems to be a lot of Jolida for sale on Audiogon. My guess would be that people are starting with Jolida gear and then upgrading to other gear.

I suggest that you listen to your Jolida for a while and decide if you really like tube sound. If you do but aren't quite satisfied with the Jolida sound, rather than spending money on the Jolida, I would upgrade to a better amp.

I like the Primaluna gear. It has an autobias feature which saves you the trouble of wondering if the output tubes are properly biased and ensures that you're always getting the best sound out of your tubes. There are many reviews and threads on the Primaluna amps and generally people like them.

So my advice is listen, read and then decide on your next move.

There are trusted tube dealers who you will probably read about in your studies who can advise you on better tubes at a reasonable price. Tubes can have a pretty significant effect on the sound you get. Good luck!

The above notes on the minor tweaks initially listed are sure good ones. I too would begin there.

Cabling thereafter. Interconnects mainly.

Then a good rack.

Then… what ever and where ever you wiah to spend some dough.

I owned that adcom amp many years ago...very harsh sounding but powerful...if you haven't done so run a dedicated 20 amp line for your gear. tube gear is susceptible to vibration so use good isolation techniques........footers, decent rack etc.....if you have not treated your room you should do so since the "shrillness" might just be your room acoustics.....after all that's done I'd experiment with tube rolling to see if you can get the exact sound you want...the 34 tube is pretty inexpensive and there are lots of options.

Spin some LPs

I don't own a Jolida amp but all the tube amps I have owned have benefited from certain special kindnesses.

The first is to get them down to the floor if you can. Bass gets better. Next is footers. Some swear by brass cones or spikes, others by soft footers, I use brass cones myself, bought from EdenSound. You can put the footers between the amp and the floor or you can spring for a rock maple platform and put the amp with its footers on that.

Herbie's tube dampers, first on the drivers, then the output tubes, come next.

Last comes a premium power cord.

Now I purposely didn't mention NOS tubes. The small driver tubes make a lot of difference, but if you're a NOS beginner, it's a jungle out there. Your 12AX7s are among the most expensive. 12AT7s are a little easier on the wallet. You can look for NOS output tubes if you like but you need 8 of them -- a pretty penny if you must have, for example, vintage Mullards.

I'd start with the footers -- look into brass cones or maybe Herbie's Iso-cups -- and meantime do some research on the NOS tube side.

Have fun !