A little help please...I just bought a Chinese, Zero Zone preamplifier that purports to be a Conrad Johnson clone. It has four JJ ECC83S tubes currently. It sounds great! But if I wanted to roll some new/different tubes, what would you recommend? Do I gain anything in a preamplifier design with matched tubes? Sorry, I cant find a schematic anywhere on it's design topography.......Only this quote in the literature..." This preamp is reference the famous conrad-johnson CL Circuit , designed with double-single independent design, physically separated 100% left and right channels, independent hierarchical grounding." Thanks
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" This preamp is reference the famous conrad-johnson CL Circuit , designed with double-single independent design, physically separated 100% left and right channels, independent hierarchical grounding."
Very Chinesium and I wouldn't believe a word of it.
An ECC83 is a 12AX7. Knowing this type of pre amp I wouldn't think there will be any gain to trying different valves apart from some may have a quieter noise floor.
If you still want to spend money on valves, 12AY7 is different, sound wise, because it has different characteristics, as all of them do.
Ensure the heaters are wired the same way as the ECC83.
Very Chinesium and I wouldn't believe a word of it.
An ECC83 is a 12AX7. Knowing this type of pre amp I wouldn't think there will be any gain to trying different valves apart from some may have a quieter noise floor.
If you still want to spend money on valves, 12AY7 is different, sound wise, because it has different characteristics, as all of them do.
Ensure the heaters are wired the same way as the ECC83.
You might be interested in the videos about this preamp posted by Skunkie Designs on YouTube. It's the same Zero Zone pre that claims to be a CJ clone. She purchased the kit version, built it, and then measured it and compared its performance to two other Chinese preamps. She shows the build process in detail, step-by-step. I don't recall if she did any tube rolling or not or if she shows a schematic.
The other preamps in her shootout were an alleged clone of the Marantz 7C and a 6SN7 design.
Here's the first post in her Zero Zone CJ build series:
Lot's of excellent videos on her channel, check it out.
Thank You....The problem with these Chinese HiFi products (Among Many) is there are dozens of version of the same product. We have no idea what "Bag Of Parts" she received. This PREAMP I have does not have a model number anywhere on it or the shipping box, and of course, "Zero" instructions. The only place that calls out a model number is on one of the PCBs. If you do a search for that PCB model number, a whole bunch of Preamps pop up. All look alike externally, but when they show an internal photo you can easily see differing components and sometimes totally different topography. So when you order one, you have no idea what you are getting. Sure, you can send it back if not satisfied with a $150 shipping charge! I paid $200 and it was operating fine for the previous owner......I've lost way more than that in ten minutes at a casino! So far, it is a fantastic preamp with the First Watt F5 v2 amplifier and Magnapan MMGs or KEF LS50 Metas....... Very happy....
I would have turned these around, keeping the board and the input/outputs flush to the backside. Sliding
the board to one side the power cables can be routed to the power switch and transformer mounted at front.
The power cables could be screened to prevent noise leaking to the board. But the main point is
to keep signals as short as possible.
Huh?? I'm almost afraid to ask . . . but what are you talking about and what does it have to do with the preamp discussed in this thread, which has been dormant for over 8 months???
He's referring to OP's tongue in cheek response earlier about losing money.
I like the Gold Lion 12AX7s in the all-tube output stage of my DAC. They appear to be very well made and non-microphonic. I think they're one of the best new-manufacture 12AX7s, and I've tried quite a few. There's always Telefunken and Mullard, of course, but they are so expensive now. An alternative is the Brimar, which is a good bit more affordable. A friend uses them in the same DAC and he's pretty picky. He feels they're very similar to the Mullards. I have not tried the "new" Mullard reissues.
I strongly suspect CurbanZaklondi is setting up a spam blitz, probably for an online poker site. His other post suggests his whole family does it.
It really is..
You've done a super sano job on layout and construction...
Hats off Rb!!
Jim
Another rolling: the coupling cap Between the stages. Some give a slight delay hence bounce/overshoot with feedback on a square wave.
5751 is nice. Amplification slightly lower, so with feedback closed the distortion changes; soundstage often improves.
The black anode has a very nice build.
5751 is nice. Amplification slightly lower, so with feedback closed the distortion changes; soundstage often improves.
The black anode has a very nice build.
Back to the OP's question: As J/J ECC83S feature frame grids, hence represent the most recent step in tube development, I don't think theres any good reason for replacing it by others. Remember Telefunken's overly hyped and eye watering expensive ECC803S are of the very same technology.
Best regards!
Best regards!
Are you sure about the JJ ECC83S featuring frame grids? I searched for it on the JJ Electronics site but can't find it.
I think confusion is caused by manufacturing methods.
This from Watford Valves
"The JJ ECC83S uses the anode construction pattern of the frame grid designed Telefunken ECC803S. Though it is not a frame grid valve this design has many advantages when used in guitar amplifiers. The solid internal rigid structure which is internally braced makes this valve very low in microphonics".
1. The JJ ECC83S tubes have Spiral Filaments. A good thing for any AC powered small signal tube filaments.
Does your preamp have AC power, or DC power; but remember for all preamps that do have AC filaments Spiral filaments are best.
2. Eurotubes.com re-tests all the ECC83S tubes that they get from JJ in Slovakia.
Very importantly, that includes a test for Microphonics, Hum, and Noise.
3. Eurotubes also sells the ECC803S, it is the Long Plate version of the ECC83S.
They have Spiral Filaments too.
They also are re-tested the same way, after they come from JJ in Slovakia.
Your preference, or get both and try for yourself.
Does your preamp have AC power, or DC power; but remember for all preamps that do have AC filaments Spiral filaments are best.
2. Eurotubes.com re-tests all the ECC83S tubes that they get from JJ in Slovakia.
Very importantly, that includes a test for Microphonics, Hum, and Noise.
3. Eurotubes also sells the ECC803S, it is the Long Plate version of the ECC83S.
They have Spiral Filaments too.
They also are re-tested the same way, after they come from JJ in Slovakia.
Your preference, or get both and try for yourself.
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