Official Jolida JD9 thread
- Thread starter helios660
- Start date
Do you have the AD797? Did you test them in the JD9 in comperance with the OPA 627?
bobins08
Celebrating Life
The LT 1028/1128 were chosen for stage 1 because of their lower noise characteristics. Cost has nothing to do with it. There are a lot of folks who started with 627s in the first and second stage and some switched to 1028's in the first stage to make the unit quieter. I am reading that some are using them in the second stage as well.
I do think that 627's in all positions is a good way to go without obsessing over things. As with anything this is different stokes for different folks. We hear different and our systems are integrated to other components differently.
My JD9 sounds excellent but as I continued to refine all the components in my two channel system I found that the JD9 was a little bit hot and thin sounding when used in combination with my custom tube preamp and my tube power amp. I have better luck with SUTs and SS phono stages when using tube preamps and power amp stages.
I am running the JD9 in my home theater and it sounds fabulous. I can get very high quality vinyl playback with my Denon Surround Sound Receiver with the JD9 connected to a line stage.
cheers, Bob
burgerbasist
New Member
Question for all of you lovely Jolida people...
Has anyone ever seen a JD9 with only low outputs, no high outputs? I'm looking at buying one, and I don't know much about them, and I found one that has no high outputs. The spot is there, but instead of female RCA ports, there's just two holes where they used to be. The guy selling it inherited it and knows little to nothing about it, but he says he was told there was once a "low output only" version which I've been able to find no info on.
I'm wondering two things... First, was there a model from Jolida that came like that, or was this unit likely tampered with? Second, if the high outputs were removed, in theory, assuming one can solder and that's the only thing that's wrong with it, would that be fixable? It seems kind of shady to me, but it's close to my house so I could probably pick it up and take a look first, and the price is right, so if I can fix it, I might make the jump. Any insight would be greatly appreciated.
Thanks!
Has anyone ever seen a JD9 with only low outputs, no high outputs? I'm looking at buying one, and I don't know much about them, and I found one that has no high outputs. The spot is there, but instead of female RCA ports, there's just two holes where they used to be. The guy selling it inherited it and knows little to nothing about it, but he says he was told there was once a "low output only" version which I've been able to find no info on.
I'm wondering two things... First, was there a model from Jolida that came like that, or was this unit likely tampered with? Second, if the high outputs were removed, in theory, assuming one can solder and that's the only thing that's wrong with it, would that be fixable? It seems kind of shady to me, but it's close to my house so I could probably pick it up and take a look first, and the price is right, so if I can fix it, I might make the jump. Any insight would be greatly appreciated.
Thanks!
bobins08
Celebrating Life
I have never heard of a JD 9 in the configuration you speak of with one set of outputs. You can call Jolida and ask.
Can you take some pictures of the inside and we can tell you more? Most likely a modified unit.
My position on the JD 9 design is well documented here. There is a surplus of gain on the high outputs, making it hard to use with MM carts that have an output of >1.5 mv, which is most of them btw. Thus, the need for the low outputs. The low outputs are derived from the exact same circuit as the high, only passed through a voltage divider circuit that reduces the signal by ~20 dB. This extra set of discrete components causes a slight degradation in SQ but to be honest a properly modded unit sounds quite good with either set of outputs.
I am thinking that whoever modded this unit uses it only for MC, or they reduced the overall gain such that only one set of outputs is needed to support both MM and MC.
Listen to it and post pictures if possible.
Cheers, Bob
burgerbasist
New Member
Thanks for the info! I'm going to check it out today, so I'll see if I can get some pictures.
I know the JD9's not the best unit, but I have a modest setup, so I think it'll do me well. I'm currently running a Music Hall MMF2.2 SE, with a Music Hall Tracker cart, through an Audio Technica AT-PEQ3 phono stage, and then into a Melody/Onix SP3 tube amplifier. I'm interested in getting into some modding and tube rolling, which I've read can give you big sound gains with the JD9, so as long as this unit works, I think it's a decent move. Anyhow, pics to come (hopefully).
Thanks again,
Dan
burgerbasist
New Member
Alright, I ended up picking the JD9 up, and it works and sounds good. I've attached some pictures with the cover off. This thing has definitely been modified, as it came with a printout of an email that said the following:
"Hi,
So here is the list basically of the mods done of that unit.
Input Stage-
-Wima film caps replaced all small coupling caps
-Nichion audio grade gold label electrolytic caps replaced all Chinese electrolytics
-Revox Film caps replaced the generic orange drop main film caps
-All wired in Cardas Teflon wire
Output Stage-
-All resistors replaced with Caddock Film MK types one Halcro resistor used
-Main output caps replaced with Dynamicaps cheap Chinese orange caps removed
-All wired in Cardas Teflon wire
-All "Quick connects" removed and direct silver soldered to board for wiring harness
Power supply-
-All Electrolytics replaced with a mix of Black gate and Nichicon caps, then bypassed [] Fast cap Film caps
-All Diodes replaced with Schotkey fast recovery rectifiers
-One RFI ferrite clamp added to transformer wire harness
-Fuse has a Ceramic slow blew replacing the base glass fuse
Chassis Damped with dynamat type sheets.
Thanks, good luck"
Note that where those brackets are the email went off the page, so I think there's a word or two missing.
Also, it's a good deal louder than my last phono stage (I'm running my tube amp at about half the volume I was before with the sound coming out of the speakers at the same level), and he had it set for MC, while I'm using MM. I'm wondering if the single input could be high output, but I haven't been able to be sure yet.
Anyhow, if anyone would be willing to chime in with any opinions or information about the above or the photos, anything would be appreciated. I'm doing research myself, too, but I'm pretty new to this, so the more info I can get the more I'll learn.
Thanks again, you guys are awesome!
Dan
bobins08
Celebrating Life
^^
Hey Dan,
Looks interesting. What Cartridge are you using? One of the pictures shows gain switch 1 up. Since you mention it is much louder try all switches down.
It appears that the prior owner did a lot of good things to reduce noise and blacken the background which is one of the weaknesses of the stock JD9 IMO.
He replaced the wires going to the output RCAs with Cardas and got rid of the entire voltage divider network for the LOW Outputs. This is not a bad move if you plan on running only MC carts or other carts with 1.5 mv or less output.
I cannot tell if his mods anything to change the overall gain. If he left all the resistor values the same and is still using 12AX7’s on the output stage then the minimum gain with all switches down is ~ 55dB. If you are running a MM or MI you will have a lot of gain, probably too much.
Can you take the cover off of the big rectangular box and take some pictures to show us what changes in the solid state section? While in there please take note of the p/n’s for the 6 op amps (they are IC installed in sockets). Upgrading them is a big benefit.
Also take note of the tubes and tell us what is in there. My experience is that good NOS 12AX7s sound much better than both the stock Chinese tubes or today’s production tubes.
Thanks, Bob
Hey Dan,
Looks interesting. What Cartridge are you using? One of the pictures shows gain switch 1 up. Since you mention it is much louder try all switches down.
It appears that the prior owner did a lot of good things to reduce noise and blacken the background which is one of the weaknesses of the stock JD9 IMO.
He replaced the wires going to the output RCAs with Cardas and got rid of the entire voltage divider network for the LOW Outputs. This is not a bad move if you plan on running only MC carts or other carts with 1.5 mv or less output.
I cannot tell if his mods anything to change the overall gain. If he left all the resistor values the same and is still using 12AX7’s on the output stage then the minimum gain with all switches down is ~ 55dB. If you are running a MM or MI you will have a lot of gain, probably too much.
Can you take the cover off of the big rectangular box and take some pictures to show us what changes in the solid state section? While in there please take note of the p/n’s for the 6 op amps (they are IC installed in sockets). Upgrading them is a big benefit.
Also take note of the tubes and tell us what is in there. My experience is that good NOS 12AX7s sound much better than both the stock Chinese tubes or today’s production tubes.
Thanks, Bob
burgerbasist
New Member
Thanks for the info, Bob!
I'll grab those pics this evening. As far as my cartridge, I'm currently using a Music Hall Tracker. It's MM with specs as follows:
frequency response 20Hz-20kHz±3dB
channel balance 2dB @ 1kHz
channel separation 20dB @ 1kHz
sensitivity 5mV±2dB
static compliance 16mm/N
equivalent tip mass 0.7 mg
stylus type elliptical (user replaceable)
load resistance 47 kΩ
load capacitance 150-400pF
internal inductance 560 mH
internal resistance 700 Ω
weight 4.2g
tracking force 1.5-2.0g (1.7g recommended)
I tried to match the gain switches with the load resistance. I'll try it tonight with no gain switches on.
Thanks again!
Dan
burgerbasist
New Member
AFAIK it was not replaced with anything. He said he was selling his uncle's stuff, who passed away.
bobins08
Celebrating Life
The gain switches are the bank of 3 and are independent of the load resistance. Put them all down for MM. That will give you more volume control with your pot ands reduce some sizzle in the sound.
On the bank of 8 set it 47 K (Sw 4 up) and 100 pf (Sw 6 up). All other switches down.
burgerbasist
New Member
Ok, I'll try that tonight. Should I look at lower output MM carts, as well? I can cut my output in half (down to 2.5mV) by moving to a Rega Carbon for dirt cheap.
tlarwa
Vinyl Lover
The answer to this question may be in this thread somewhere, but I don't seem to be able to find it through the search function...
Can I run two tables through the JD9, one connected to the high outputs and one to the low outputs? I just picked up a second table (VPI HW-19 MkIII) and want to be able to switch between that and my Marantz TT15S1. I realize that the cartridges will have to both work with the dip switch settings. And obviously only one table would be powered on at a time.
Anyone? Thanks!
Can I run two tables through the JD9, one connected to the high outputs and one to the low outputs? I just picked up a second table (VPI HW-19 MkIII) and want to be able to switch between that and my Marantz TT15S1. I realize that the cartridges will have to both work with the dip switch settings. And obviously only one table would be powered on at a time.
Anyone? Thanks!
bobins08
Celebrating Life
No. You are mixing up inputs and outputs.
The JDP has one phono input and two possible outputs. The outputs are derived from the same input source; the low output has a voltage divider network that reduces the gain of the high output by ~20dB.
You select which output to use by first determining how much gain you need going to your preamp's line input. In general, MC will use the high output and MM will use the low output. You set the switches for the one cartridge that it is supporting.
Cheers, Bob
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Madskaman
Member
I actually tried this. I ran 2 inputs to the Jolida via a y connector. This was not successful. I ended up "loading" one cartridge with the other. Another issue is that my Sony turntable has a muting circuit that grounds the signal when it's not being used. That ground ended up grounding both carts at the same time. I'm sure there are plenty of other reasons why this did not work. What I ended up doing was making a separate box to control both tables and route that output to the Jolida. I suppose you could do all that inside the Jolida with a switch of some type. Ultimately, I ended up with a second phono pre.
Madskaman
Member
I've been playing around with power supplies lately and I've decided to go back and take a look at my Jolida JD9. I've always been unhappy with the bridge rectifier on the solid state board. I'm going to make a bridge out of some ultra fast, soft recovery diodes. I'm also considering adding larger power supply caps outside of the case. Has anyone tried this?
Madskaman
Member
I went ahead and modified the power supply to the solid state board. I made a bridge from ultrafast, soft recovery diodes and added some 1000uf Elna Silmic ii capacitors inline with the stock power lines going to the solid state board. I then completely removed the diode bridge on the ss board and bypassed it. This way I was able to use the same power connector now with +/-24 volts and ground rather than AC.
I'm very happy with the improvements. Much quieter and more dynamic. It's still a bit on the lean side. I'm not sure if my cartridge needs some more break in time or if I'll have to revisit the coupling capacitors on the ss board to address this. I have the first one bypassed and it may be costing me some warmth. Regardless, I'm very happy with this simple tweak.
I'm very happy with the improvements. Much quieter and more dynamic. It's still a bit on the lean side. I'm not sure if my cartridge needs some more break in time or if I'll have to revisit the coupling capacitors on the ss board to address this. I have the first one bypassed and it may be costing me some warmth. Regardless, I'm very happy with this simple tweak.
bobins08
Celebrating Life
Sounds interesting. Pictures would be appreciated if possible.
I would look at the coupling caps for the issue with lean sound.
Cheers, Bob
