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As opposed to my usual confused state.I just tested my new JoLida JD 9 phono preamp to see if both output levels use the tubes (JoLida test) and am now wondering how did they do that? What is going on inside that black box? (Silver boxes inside actually.)
Here's what I see inside. Input terminal box has all the dip switching circuits and then the signal goes to the ss board with the tubes integated into the board. From there the signal goes to the HI and LO output terminals (another smaller silver box) WITH ONLY ONE SET OF WIRES!
If I pull the tubes, the signal still gets to the outputs, but it's obviously not being powered by the tubes. The output is much reduced and noisy. So how do you get dramatically different output levels from one set of wires? Do the RCA interconnects when plugged into the output terminals serve as a passive switching mechanism for the amount of gain to feed through the tubes and into the output terminals?
(As Rodney Dangerfield whispers to the movie audience during class in Back To School: "Nice guy. Really seems to care. About what I have no idea.")
Tom
Follow Ups:
Back in the day, when CAT and Audio Research were duking it out for the best vinyl sections on earth, a little company called Precision Fidelity released the C7 and C7A preamps.According to TAS, this was the best phono section they had ever heard. The design allowed you to leave the power off and it functioned as a passive preamp. Power it up and it was a tube preamp.
Precision Fidelity went out of business and slid into obscurity.
However, some engineers recognized genius when they saw it, and the Jolinda is a modern version of the venerable C7 and C7A preamps. This is a very good thing!
Hope this helps some.....
By the way, my modified C7 is still my favorite phono preamp by a long shot, and I have heard a great deal of preamps in my life. I have had some mega buck preamps at my home, and none have produced a better sound stage, more accurate timbral accuracy and more smiles per miles.
Tube rolling can be lots of fun with my preamp. Right now I am using 4 12AX7 Groove Tube Mullard copies, and two Holland Amperex Buggle Boy 6Dj8's. I just love everything about the sound.
" ... Jolinda is a modern version of the venerable C7 and C7A preamps ..."You mention 6 tubes, the Joilida uses 2 (12AX7). Can't see how it could be very close?
> > > You mention 6 tubes, the Joilida uses 2 (12AX7). Can't see how it could be very close?Perhaps Jolida discovered the truth about tube sound and found they could use op-amps in place of most of the tubes and only use a couple of tubes to provide the requisite distortion to produce the tube sound.
Just an educated guess!
reluctance to appreciate what is possible with so-called ancient technology until first hand exposure, e.g. tubes, conical stylus cartridges, etc.No biggie! Mind you there are lost souls that can't even recognize good performance, their biases so resolute they are incapable. Those types can be fustrating, but that's not something open minded folk like you and I need be overly worried about!; truthfully there was a time when I had my doubts about you in this regard, now I know better.
Jolida has discovered something but they still make their best products using all tube circuitry. Their discovery is in this case "less is more" but it is not quite as it may seem or as you have suggested. It is simply about cost. Jolida has two goals, one being to faithfully reproduce the musical event in your home (not necessarily the recording but the actual event, a distinction that they are happy to point out); two being the most affordable product to do so. They may not hit a home run with every product they swing at but they have a good batting average.
The whole point of the JD9 is to build a unit that sounds very nice and that is quite affordable. Also one that fits into their system well. Their tube amplifiers are pure tube integrated amps with line level only inputs for the most part. The JD9 is very solidly built and is large enough to be used as a base for these amplifiers even with one of the heavy muthas such as a JD302B or JD502B resting atop. That gives them the required phono input with a separate power supply and substantial shielding (you can read about that in another post) without having the sound get too tubey as vinyl is already quite warm in many systems. Of course using an opamp design makes the cost much lower and packs quite a bit of function and reliability into a small space. I can't argue with them in this regard as I also favor SS phono designs as the critical first stage of gain. What they then choose to do is to warm-up the sound with a tube buffer that really makes the less expensive systems sound a lot bigger than they would otherwise have any right to.
So Jolida's big discovery is realizing what people want and being able to deliver it. That doen't make them the best in a crowded field but it does give them the edge in their market segment and it makes their customers very happy Buddahs indeed.
-Bill
Ah yes; "Ridiculous stupidity:""Perhaps Jolida discovered the truth about tube sound and found they could use op-amps in place of most of the tubes and only use a couple of tubes to provide the requisite distortion to produce the tube sound."
My whole system is a POS compared to everyone else's. But I sure am enjoying all the distorted sound coming from my POS speakers. It's a good thing I bought that expensive POS integrated amplifier too. We all know that integrateds suck. And that POS cartridge really should be taken off and melted down. It's so obviously shitty. And how stupid could I have been to buy such a poser turntable. It's not worthy of being called a turntable. What a POS tonearm and motor. I can't believe that such a hacker system could even produce sound let alone be recognizable as music. Man, I cannot believe how much money I've wasted on all this worthless stereo gear. I'm such an idiot.With a big smile on my face every time I sit down to listen to it all. Peace be with you.
You should update your system components in the user profile section to reflect your full-on crappy tastes! Jolida specifically makes gear to be fun to listen to and affordable, not to impress the graph readers or the Jones' ultra-fi crowd.
-Bill
That is really funny. Funnier even than "wooden tonearms that hang from a string". Wow. -stark
From Arthur Salvatore's Recommended Components...PRECISION FIDELITY C-7 (LATER MODELS)
I sold this model when my store opened back in 1981. How I could have forgotten it until now is something I would prefer not to dwell on, but it should have been here from the beginning. This is a "classic preamplifier", with a design far ahead of not only its own time, but even up to today. In fact, our current audio market is begging for an updated version of it.The C-7 was essentially a high quality (tube) phono-stage with two volume controls, a couple of extra (passive) inputs and no line-stage. This is "the dream design" of today's audiophiles who have phono-centric systems, like me. (My own preamplifier, the Jadis JP-80, was heavily modified to copy the basic design of the C-7.)
It's been some time since I heard one of them, but I remember their sheer natural quality and the cleanness and quietness that is consistent with no line-stage. The people who bought them, if they could live with the low-gain, loved them. (I'd love to hear a modified version, with the best caps available today. I would love even more to hear an all-out modern version of this design.)
I remember that the original C-7 had some design problems that translated into sonic problems, so look for the "A" or "Revised" versions. I don't know if the original can be converted. The C-7 should be modified with better capacitors, just like all the other preamplifiers from this era. They also require a high quality step-up device for low-output moving coils.
Recent- One reader just purchased a C-7 based on the above recommendation. His take:
"...soundwise - Wow! Lumi is taking a long rest. This thing sounds a bit dark (like most passives in my system, probably the amp), but it is so dynamic, immediate, transparent, and not greasy or euphonic or juicy. I'd venture to say it is rather accurate. Of all medium priced preamps that I've tried, and I've had many, including many Bruce Moore designs, this one is by far the best sounding, with great MM phono. It beats Magus by a wide margin and phono is a lot quieter (uses two solid state regulators). Thanks for a great suggestion..."
Bottom Line- If I was on "a strict budget" for a preamplifier, and with the choice of ANY model ever made, the C-7 (modified) would be my first choice.
I have posted the url on a response to Garth down below.I have the TAS article somewhere, but then again I am not sure I will ever be able to find it. He compared the PF C7 to the CAT tube preamp which at the time was considered the top of Class A. I believe this review was authored by Harry Pearson.
Question was circuit specific.Answer was a non-sequitur about something else entirely.
Now you cite some fluff-work from a couple of the major cranks in audio to support your non-sequitur.
Brilliant.
Admit it, you are out of your comfort zone on this matter.I never gave technical advice, just a historical perspective of the circuit design.
More than you provided by the way.
Please take the year off now, no one wants to hear your opinion any more.
views on Salvatore very far from universal. That said, you've every right to your opinion of course.However, I must admit that the exchanges here seem to have little bearing on proposed relationship between the C-7 and Jolida JD9. Could you comment on that, as a JD9 owner I'm interested in the connection.
You may agree with Salvatore or disagree with him, his opinion is simply a starting point for research.Anthony Cordesman, Harry Pearson and others also commented on the C7 and C7A designs, I just did not have their reviews handy last night.
Basically, Precision Fidelity was among the early designers to utilize hybrid technology for amps and preamps. The goal was to produce the best overall sound quality in the most natural sense.
Several of the current phono designs use just a single tube, with each section of the tube feeding the two channels.
I have heard great things about the Jadis, and I hope it brings you years of enjoyment.
That's it! Well let me remind you that in the post where you implied a relationship between the C7 and JD9 you also wrote ... "Back in the day, when CAT and Audio Research were duking it out for the best vinyl sections on earth, a little company called Precision Fidelity released the C7 and C7A preamps...".Well I don't know when the C7 was released relative to ARC SP9 but I can tell you most definitively that the SP9 is also a hybrid design (I owned a SP9 MK II for almost a decade), the first gain stage in the phono section is SS (FET based I believe), the second tube based.
So much for the strength of the relationship if the fact that they're both hybrid designs is *it*.
I wonder how many poor souls have actually wasted their hard-earned dough on "T4's" "expert" advice.The archives are beginning to burst at the seams with erroneous assumptions, useless tweaks, and bald-faced self-promotion that would make that fitness infomercial guy with the blonde ponytail blush.
Cmon, what's advice, really, but telling everybody else what your imagination tells you ?
And then swearing up and down you've got pretty serious experience to back it up ??(and then shutting up real quick if they figure it out)
Let's approach this without those nagging doubts presented by so-called "reality" .... okey dokey ?
You would remember that I have told everyone here at the asylum that I have no agenda, I am a musician first and an audiophile second. I have a DIY kind of personality and I love to tweak.So if I enjoy some very well designed and engineered vintage stuff, why degrade me personally?
I don't care what you own, as long as you like it FINE.
I buy things that have value, tweakability, and have the ability to sound like real live music.
When someone has a serious question about how a circuit works,try letting your imagination rest unless you have a serious, evidence-based answer .......
Do not try and imagineer an answer to a technical question -----
---just on the off-chance that someone else might really know.
Your answer here displayed a spectacular ignorance of the circuit, and the specifics at hand.
Grow up and become an adult.
Or give us another adolescent reply.
Just curious!
...a small fraction of those who were suckered into buying that squeaky little AT OC9 POS you used to tout ad nauseum.
Poor soles! Oh, well! Such is life!
.
.
Hey Fretless, I've got a challenge for you. I'll trade you my DRT XV-1 for your XX-2. I'll even send you my XV-1 first and you can mount it and listen to it. If you like it, simply send me your XX-2 for an even trade. If you don't like it, send it back to me. If you have any balls, send me your mailing address in email and I'll send you my XV-1 immediately.
Afterwards, when we're all done laughing our asses off.
How many hours do you think it has on it?
Lets take this off-line: Mail sent.
I received your email. It does not have your name or mailing address. It only asks me how many hours I have on my XV-1. I can tell you that I have way, way less hours on my XV-1 than what you claim to have on your XX-2.I can not send my cartridge to someone named Fretless with no mailing address. Either you have the balls to send me your name and address or you don't. Personally, I think you are totally full of bullshit. But, if you have any balls and want to trade an almost new XV-1 for a much more used XX-2, simply send me your name and address and I will mail my cartridge to you. It seems to me that you have nothing to lose but your identity.
If you want to take this off-line, simply send me your information or else quit.
Fretless and JD just like to criticize others opinions and recommendations. Then they try to impune our experience and our motives.
I'll send you my address.
.
"This is "the dream design" of today's audiophiles who have phono-centric systems, like me. Bottom line-If I was on a strict budget for a preamplifier, and with the choice of ANY model ever made, the C-7 (modified) would be my first choice."I think that this preamplifier sounds remarkably clean and accurate, with a very smooth and musical presentation-probably the finest phonostage I have ever listened to."
Arthur Salvatore
.
If so I'm glad I didn't buy one.
If you read the test post I mentioned that the signal without the tubes in place had much lower gain. The tubes are providing both amplification and that wonderful (to some) tube sound and versatility. That's a good thing if you're looking for it, right?I never intended for my questions about the JoLida JD 9 to become a competitive (or disparaging) comparison with other phono stages. I don't really care if the JoLida JD 9 is or isn't the best. Listening to home stereo music is not (normally) a competitive event. I merely was curious about it's design and circuitry. Between my conversation with a helpful JoLida Representative and the helpful advice and suggestions of several Inmates, I am quite confident that my JD 9 is working as it should and am very satisfied with the music I hear coming from my home stereo.
If your phono preamp is better than the JoLida JD 9 than I'm glad you found one you really like. But please don't knock JoLida unless you know for sure what you're talking about.
can confirm what you say.Basically the chromed metal box inside holds the initial stages of amplification. This is pure SS, op-amps based.
After that the signal goes to the tube stage. Hence the JD9 is a 'hybrid' phono stage, SS and tube, *not* pure tube.
From there, via a single path (as you have discovered), the signal goes to the outputs.
The HI outputs are connected directly to the tube output stage, the LO outputs go through what appears to be a passive network. It is my suspicion that this passive network is actually nothing but attenuation to lower the output level, i.e. to allow get the level down if using a MM or high-to-medium output (H-M) MC cartridge.
Hence, the JD9 would appear to be primarily a low output MC phono stage, with passive attenuation on the LO outputs to allow use with MM (or H-M MC).
The issue here is really the crappy manual. There would be no need for speculation if they simpply did a better job on the manual.
---
Anyway despite the confusion the JD9 is an outstanding phono stage IMHO. I use mine with a Denon DL-103 and am absolutely floored by the performance. The settings I use are: HI outputs, lowest gain setting, and 100 ohm loading. Teamed with a moderate gain line stage (10-12db) the next higher (JD9) output setting might be best; gain setting should be set by ear, forget the numbers.
IMHO the JD9 just as substaintial a bargain that the Denon DL-103 itself. The combination is very likely unbeatable at anywhere near the price.
I use the stock tubes. The only alternatives I've tried are the Sovtek LPS tubes. These make the JD9 obviously less noisy but I prefer the sound with the stock tubes ... I'm more interested in the music the system produces and a little extra noise for positive gains in musicality is a no brainer for me ... I'm that way.
The JD9 benefits from sitting on 'squishies'; I use the $4.00 each FocalPods from Parts Connection, I suspect VibraPods would be just as effective.
---
The Jolida JD-100 CD Player is just as remarkable as the JD9. I've had at least one CD player that cost twice as much (Arcam CD92) but have not enjoyed listening to CDs until I got the JD-100 ... it is *the* vinyl lover's CDP. With the JD9 and JD-100 serving front end duty my system is so scary good I am in a permanent state of awe. If I pretended to be any less impressed I'd be lying through my teeth. Nuff said!
I think I lucked out on this JD 9. I've never auditioned a phono stage and bought the JoLida sight unseen. Teamed up with my new turntable I'm hearing a richness and details in the music that I'd never heard before. A few times I've had to look up to see what I was listening to because the music sounded so much different (better) than I had experienced with my more modest gear.You're right about the product description. It's a bit confusing. After talking with the rep from JoLida the design and features all seemed to make sense (other than the tube circuitry). It's well thought out and quite versatile. All they'd need to do is take what he told me about the JD 9 and incorporate it into their user's manual and product description. His descriptions were clear and concise.
Tom
PS: The JD-100 is on my short list. In fact that's how I discovered the JD 9; looking at hybrid cd players but needing a phono stage.
Unplug everything and measure the resistance between the hot terminals of the hi and low RCAs.
Using an inexpensive multi-meter, and with the 1K Ohm meter adjusted to it's minimum (maximum?) range, (there's a small inset thumbwheel on the side that adjusts the ohm meter sensitivity and I have it set at it's most clockwise/upward position) I get a reading of 0.8 ohm. The ohm meter works opposite of the other meters, right? That is, it reads zero (to the far right of the meter dial) unless there is enough resistance to register?Thanks for taking the time, Mark.
> > > (there's a small inset thumbwheel on the side that adjusts the ohm meter
> > > sensitivity and I have it set at it's most clockwise/upward position)That is not a sensitivity control; it is a zero asjustment. You are supposed to touch the leads together and adjust the thumbwheel until the meter reads zero. You should do this each time you measure ohms and each time you switch to a different resistance range.
Tom
Tom
You are looking for a resistance bewtween the active terminals of the high and low level outputs. This might tell us what's going on.A photo would be useful also.
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