Users browsing this forum: No registered users and 1 guest
Jolida JD9 phono preamp Upgrade Guide:
Intro: The JD9 is a very good phono preamp but with some easy upgrades it can perform well with the over $1,000 preamps out there. This guide will go through upgrading the JD9's tubes, opamps, caps, and installing dampening material into the case.
You can download the complete step by step guide at the url below:
Nifty mods there.Nice write up too. What made you decide to replace the opamps? Not being familiar with that circuit, I dont know what exactly is their function.
From what I can see those vents are pretty small, and even before you put the damping material in there seemed to be "tracks" going out indicating a heat issue, perhaps its supposed to be that way though. You mention that you took the shields off, those will keep in heat too, and so will the damping...not necessary a bad thing here, more heat can make them sound better, but the tubes just may not last as long. If the sound is that much better... a worthy tradeoff, I would think. Believe me I know how much of a pain it is to pull and put a piece of gear back into service, especially something like this that really relies on the rest of the system. What I really would of like to of seen though is a A B C comparison, to find out which mod made the most difference. Finally and before you hate and ban me....get a desoldering iron!! Makes easy work of literally sucking the solder out of the joint. That way not only does the old piece come out easy, you get to put new solder(and flux) in that joint. Oh...ok not finally(I'll pack my bags....lol), I do appreciate the symmetry of the leads on the new can caps in the back there, but that positive lead is pretty close to the can there. I dont know those specific caps, but if they are like most; the entire can is "ground" so a good jolt could cause that positive lead to contact the negative side....REALLY dont want to see that. With those types going flat like that(EXACTLY what I just put in my PV1 as a replacment), I will bend the negative right at its connection to give the positive plenty of room to breathe. Or if space is an issue go ahead and insulate that positive from the negative side, just to be safe. I'm sure the preamp "just sits there", but I have seen some very strange things happen to gear.
The opamps are involved with amplification circuit, also since the JD9 has highly variable input options to be compatible with just about any phono cartridge, it's an exceptionally important part of the JD9. One thing to remember about the JD9 is that it's an incredibly inexpensive unit. Unfortunately they do not use the highest end components (thus the price), but luckily there is a large modding community. If interested I would recommend you read this JD9 thread on audiokarma.org:
Acutally, heat is really not a problem for the unit. It does not consume too much electricity and the entire housing is made from metal and serves as a large heat sink. I would say even the vents are not really needed. If you run the unit for an hour and put your hand directly over the location of the tubes, it's just mildly warm at best. Plus, the tubes are located directly over the vents. The unit otherwise stays pretty cool to touch as is really oversized for the components (as you can see in the picture.
I specifically didn't do that on this thread as it is basically an upgrade guide, not a review. Many people have followed my guide but using different components. There is actually a fair bit of info on what specific components (tubes, opamps, caps, etc) people like in the audiokarma.org thread above. That thread has almost 800 responses! Dozens of caps and opamps have been discussed there in detail, so if interested you can read through there for opinions and reviews of specific upgrade components.
Although this was a pretty easy soldering project as there is plenty of room to work with and the board is very spacious, I completely agree, that would be a nice tool to have. I don't do too much soldering, but I'll keep it on the list of "things to get."
All good points and I agree. It's not too clear from the picture but there is actually very large clearances between all the leads and the actual caps are sitting on the dampening material that I installed. The entire caps are quite solid and don't wiggle with shaking or any motion (I checked). Originally I was going to fasten them down with plastic ties but since it was so solid I elected to leave them alone.
....and I still have an account....YAY!! lol,
will check the mod page on karma. Right now I have a Parasound SS ZPhono that works alright with my HT upstairs(all parasound. avc1800 to two hca 855 to "custom" speakers all around that are going to be replaced with some matched customs(9.2 system if my math is right...hehe...also have a parasound CSE 6.1 "system expander" that I have yet to play with)...will make my own thread for those...fairly straight forward though. The TT is going down with the CJ gear one of these years. The PV1 does have a phono input, but I plan on having a second MC table or just arm on my TT. We'll see, I have plans for a custom TT, though that is still in the sketching stage. again...another thread...lol
Again very nice write up, very sorry if any feathers ruffled....just had a seat of my pants response basically, again will read the whole mod page and may follow suit.
Everything is fine, no feathers ruffled. Quite the contrary, I always welcome any comments, as well constructive criticism.
If you are looking for an inexpensive phono preamp and are handy with a soldering iron, you can really make this unit compete with the multi-thousand dollar phono preamps, IMHO.
ACK!! a quick search on fleabay....$600 is a deal for something that will rival something costs twice as much or more(I whole hearted agree), but way outta my meager price range(especially for something that I have to throw parts at)....will have to start hunting for one that is very well "used"(or broken) that can be had for much less. I am in no hurry as I have what works now(and no MC cart either, for that matter), but will definitely put out feelers and start reading the mod thread on karma for tips. I do like the looks and design from what I can tell from the pics....even if it isnt *CJ*....
I do usually find that there are some out there that do similar mods, get tired of the gear and want to quickly move on..... and in reality they decrease the value of the unit(never know who has been soldering on what...lol). Just have to watch the boards.... Perhaps that would be a better route for me. Thanks for the info though.
Don't be fooled by the $600 price tag, you can get it for less than that. I paid $340 for mine 2 years ago (new). I think I just read on the audiokarma.org thread that somebody had just bought one for $400. It's a bit expensive, but once again, I think the true value is that for under $500 (and some mod work) you basically get the equivalent of a multi-thousand dollar sounding unit. Price is definitely a concern for me as well, but I am willing to spend a little extra for something that I don't feel the need to upgrade in the long run. I absolutely love the JD9 (modded), and it's one of the most versatile phono preamps available (in terms of cartridge settings, as well as easy modifications).
The price of the JD9 has gone up significantly in the past 3 years (relatively), you could actually get a new unit for under $300 just three years ago. There has been a huge demand for it as word has spread. There are almost no "used bargains" to be had and most of the stuff on ebay is either new units, or modded units that they sell for a hefty premium. If you really are looking for a good phono preamp that you could probably use for the next 20 years, you may really want to take a serious look at the JD9.
Of course I also highly recommend the Conrad Johnson TEA2 phono preamp (but that's $3,000).
Yeah I got about 6 pages into the mod thread you linked. Will finish it later tonight. Someone was ordering straight from Jolida for Like $400 back in 2011. ahh, if only I would of gotten in then. $400 I could possibly swing but they do seem exceedingly popular, just have to see what I can find, a quick search on audiogon was even worse...pros selling already modded versions.
Best case is I can find someone who wants to trade, I have lots of stuff. Hate giving fleabay/paypal a third of anything I sell to raise funds. Havent been around local audio circles in years, might have to eek my way back in....lol.
Still have furniture to move sometime today too. I do plan on getting the PV1 hooked up to my MV52 today, depending on time and energy, will rebuild some KLH speakers as "bookshelf" monitors. Also have JBL 4301 with the original woofer needing refoam...but right now they are the temp mains in my main HT. Need to build those speakers to replace the JBL...ahh, a vicious circle....
Who is online
Users browsing this forum: No registered users and 1 guest