@artemus_5 you’re right, your internal resistors are 47 000 Ohm, your parallel RCA plug resistors are lower (100 Ohm and 470 Ohm) for MC.
My modified JLTi has internal resistors of 500k Ohm, so i can use 100k Ohm or 47k Ohm with parallel RCA plug resistors for MM. This is the reason why i have RCA plug 47k resistors (you don't need it).
You can’t use 100k Ohm, your limit is 47k Ohm when the RCA unplugged. Both values are relevant for MM only or for external SUT.
In your situation you can add 1000 Ohm, 10k Ohm or something like that.
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@chakster @pryso Since mine didn't come with a 47K plug I figured that was the default loading. I have it switched to high gain. Again with no problems. FWIW both my wife and I liked it better without loading. Bigger soundstage. The 470ohm plug offers a more focused sound which is somewhat alluring. But speakers do a disappearing act with no loading. Much wider and deeper soundstage.
I bought mine from Jay @ Audio Revelations shortly after the shootout with several other phono preamps, most a lot more expensive. Jay picked up that line shortly thereafter. I didn't buy the OB power supply because the cost was more than the benefit which everyone had said was a tradeoff at best. Thanks for your help Gentlemen. Guess I'll call Joe and check on the upgrade & PS.
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For those who own or consider buying a JLTi, off topic but a bit of advice.
I bought an early version in the black case when originally produced in Oz. At the time they claimed a wall wart worked fine with nothing to be gained by an outboard power supply. But an audio buddy who knew a lot about electronics insisted it would and built me a fully regulated PS for mine. That offered real improvements with more solid and extended bass, a larger soundstage, increased dynamics, and simply greater overall listening enjoyment.
Later JLTi offered their own OB PS so apparently they realized the wall wart was not the best answer. So if you have a LJTi without an OB PS then I suggest you are nor experiencing the full enjoyment possible.
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Yes, mine is not the latest, but just previous (without special power supply). Anyway, i asked joe for a mod. I can go higher than 47 000 Ohm for my MM (mainly 100 000 Ohm). But for MC it is nice to have many optional RCA plugs with different load resistors. If you have 100 ohm and 470 ohm, you must have 47 000 Ohm too (for MM). So you can switch to high gain and use 47 000 Ohm for your MC. We have a club of 47k lovers for MC here.
P.S. Joe is a nice guy to talk to, i wish every manufacturer do the same for their customers. |
@chakster I thought you also had the JLTi. I was using the 470 ohm plug which came with mine. I also got a 100 ohm with it. So I may be good
I think you have the later JLTi from Australia. I see Mr Rasmussen has "updated" the JLTI. I’ve wondered if the new one is better? He offers an upgrade of the older ones. Of course, I suspect he will say it is much better than mine. So I haven’t asked him. Do you have any insight?
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I also have JLTi phono, so all you need is cheap RCA connectors to solder some cheap resistors and you can make many with different value to try what you like.
Now you have 100 Ohm and 47 000 Ohm
You need something in between such as 500 Ohm, 1000 Ohm, 3000 Ohm and 10 000 Ohm for example.
In this case you don't know yet what is the best. Just buy cheap resistors to try different loading.
You can upgrade the resistors after you will understand what value do you need for your Zyx |
Yes, definitely upgrade to metal films for this application. You don't need 1/2 watt either. |
The main factor in choosing resistors for this application is keeping the noise as low as possible as any noise will be amplified in the following gain stages. Any resistor adds an amount of noise (called Johnson noise) regardless of the conductor material, as well as that each material has its own excess noise (apart from wire wound, but that's has its own inductive properties that rule that out). So that leaves thin film resistors, which in almost all applications are perfectly acceptable or bulk metal foil (like the Vishays suggested by @chakster ) which have exceptional noise performance and are very linear, albeit at a cost.
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@chakster OK I found my Zyx box and spec sheet. It listed >100 ohm which I assume means over 100. I was using the 470 ohm which came with the phono preamp. So I may not need to make any other plugs after all. Preamp (JLTi) came with 100 & 470 ohm plugs. Still. all info appreciated
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Buy Vishay Naked Foil resistors from Texas Components on ebay (it is the manufacturer), this is the best audio resistor in the universe for reasonable price, not a snake oil !
Actually ZYX recommendation is not more than 1000 Ohm, but more than 100 Ohm like any typical MC. You can pretty much ignore it and try whatever value you like!
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The phono input loading resistors are very critical sonically. The very best sounding in my experience are Audio Note 2w Silver Tantalums. Second best are nude Vishay bulk foils. Each is pretty expensive but well worth it in my opinion. |
@millercarbon, I pretty much knew the answer when I asked the question. But I had to ask just to make sure.
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If you bother to compare it will take all of like three seconds to realize what crap cheap resistors are doing to your music. All that measures is not all that matters. My first crossover was built with Radio Shack parts. When it sounded like absolute crap I called the designer who had given me the schematic to complain it sounds nowhere near as good as I heard in his shop. Second question he asked was what parts did I use? There's so many different choices, I haven't tried them all, but for sure the ones I have tried the more you spend the better they sound. Ten resistors for a buck from Radio Shack, and you really do get what you paid for, and it ain't much. |
Give it a try, but order better ones to hear the potential. FWIW, "Kiwame" sounds great & is my resistor of choice. |
