The Jolida amps are a nice simple design that are easily upgraded. Yes some swapping of parts will bring this amp to a new level. They are much better as an amp only removing the volume control and adding a active preamp.
Some may argue that modding doesn't improve the amps but it does. The coupling caps are cheap 10 cent Chinese CBB caps. Some decent coupling caps would be a good place to start.
If the modification results in the amp being a keeper for you, Detredwings' advice might be spot on. I know people who have been very happy with Jolida mods. If however, you're seeking advice regarding the next step on the path to audio rapture, a modification is not advisable. It is very unlikely that you will see a reasonable return on your investment when you try to sell. Frankly, I don't understand the preamp into the Jolida rationale so I won't go there. More and more high end manufactures are building quality integrateds. If you're squeezing dollars, I would stay that course for the time being.
As Phaelon said if your paying to have the mods done think it through. You will loose money if you want to upgrade. I got a 502 for a steal and did the work myself.
I know the preamp didn't make much sense to me at the beginning either. It would seem that your just adding something to the signal path. The Jolida is basically a amp with a volume pot. But after reading about it in some forum's I tried it. An it made everything better. Sound stage wider and deeper, extension on both ends. Even my wife who loves music but thinks I'm a little nutty with this hobby sat and listened. Her first words were wow that sounds amazing. Doesn't sound like the same amp.
I'm not one to put things into the signal path. On the contrary. In fact I took out balance and selector controls. You can try it by putting your volume to about the 12:00 position an plug in the preamp. Not as nice as the volume control removed but it will give you a good idea.
Assuming I were to buy a used preamp to be used with the Jolida, any recommendations? To make it fairly easy, I'd be looking for tubes, a remote and under $800. I doubt there are many good contenders given those requirements.
So, to restate my original question, I am wondering if in the price range of around $1500 used is there better value in tube separates or an integrated amp? Maybe this is too vague a question, I realize there are a lot of variables. It does not sound like upgrading my Jolida is the way to go (since I can't do the work myself, the return won't likely be worth it). Can I get something that's a HUGE step up from the Jolida for $1500, or would I have to go higher for that to be a slam dunk?
if you plan to keep the jolida, changing to better parts would definitely improve.
If not, suggest you purchase a better int amp.
"Can I get something that's a HUGE step up from the Jolida for $1500, or would I have to go higher for that to be a slam dunk?"
Nobody can answer that question for you Nolitan. Getting the best sound possible out of a system involves so many variables it's almost mind boggling. You might relocate your speakers and get the type of results your looking for. On that subject, matching your speakers with the correct amp is about as critical as it gets. If you want to play complex music, your amp must be able to provide power on demand, and some speakers are much more demanding than others.
I'm sorry Nolitan, my response was intended for Meskandar.
Very fair point on the speakers question. I am using Triangle Comete XS speakers on sand filled stands. I've had them for years and love them. They are easy to drive, very fast, and believe should be able to do what I want when paired with the right electronics.
I was told by several sources that these speakers match very well with EL34 based tube amps (part of why I bought the Jolida). They are a good match I believe...just not getting the goods on complex music.
Meskandar if you know someone who does a little soldering the mods are not difficult. Here is a link that shows what needs to be done. It's for a 302, the mod would be virtually the same. http://www.audiocircle.com/index.php?topic=17354.0
If not see what a local tech would charge. I think Dave wrote the article a few years ago it was less than $120 in parts. More stuff could be added but it would get you most of the way there. You would probably be very happy.
Don't think about the preamp now. Just my advice. If you can have someone change the parts for you, it would be worth it. But if you need to send it in to have it done? You can also look for one that's modded to come up for sale.
The 302/502 are the same amps with different bias resistors. I have not looked at the 202 but I believe it is the same with different/smaller transformers? Good luck and as other said you won't know until you try.
I would suggest a different (and easy) test - try a different set of speakers. I like Triangle Comete speakers, but I doubt that anyone will describe them as bass slamming or ass kicking. They excel at exactly what you say they excel at: female voices and small instumental music.
Depending on your musical tastes, your room, your front end (analog or digital) and most importantly your ears; it's hard for any of us to conclusively advise you on how to proceed.
A new integrated amp - maybe. New speakers - maybe. Mod your Jolida - I would vote no. Any conversions will likely equal or exceed the value of the unit, and will severely lower the resale value. Better to replace, IMHO.
A person asks for help with some restrictions, and in our eagerness to provide that help, in keeping with those restrictions, we sometimes dance around the truth.
"clarity, ability to handle complex music/speed and bass"
Those represent the nuts and bolts of what makes music sound like music to me. And so far, in my experience, real gains in those areas, and not just little finesse moves, have been achieved at significant expense. Again, just my experience.
Unfortunately my line of thinking falls along with what Phaelon said. I'm looking for a significant change, anything else to me just wouldn't be worth the expense/bother. I can roll tubes, upgrade my front end (Music Hall cdp and computer audio through Music Steeamer+), etc...but what I am really after might have to wait until I have more means.
I am thinking something along the lines of a Cary or Rogue integrated is sure to best the Jolida in all areas. This will be a large expense for me, but probably where I am heading.
Meskandar, Whatever you decide, until you do, your time will be much better spent, out in the field, listening to as many systems as possible, instead of relying to heavily on these forums. Listen; discuss what you hear; listen some more; discuss... it's a process. It can be a lot of fun.
Also, I think that you are showing good judgement in trying to avoid moves that might essentially prove to be lateral. Even buying used, over the long run, each move chips away at your finances, so that when a significant opportunity comes along, you might not be able to seize it.