How it sounds was the original question in post #1
All "answers" were off subject.
if not judging mainly by collector's "value" of an iconic audio piece, then building the bare bones circuit with similar power supply should provide a clue more than reviews and opinion at the fraction of the cost of a surviing unit.
It is what is is.
Power supply execution and coupling cap type will influence the subjective impression as will associated amplifier, speakers, room, listener's hearing accuity, mood, music played, etc.
A Dyna PAS phono stage could be wired with the same feedback RIAA - the cathode follower would be gone (a good thing maybe)
Conrad-Johnson's PV1 was a fair knockoff IIRC. Other circuits may image diferently. A stripped down Stu Hegeman type based in Citation I and IV, with "anode follower" high level stage could be fun too if one wishies to explore the old ways of the golden age of Hi Fi.
One thing which facinates me - as time moved on towards solid state, designers like Stu Hegeman with his HAPI preamp and Grommes designer Al Hart, did not seem to consdier their solid state work to be inferior to their tube era designs.
It is what is is.
Power supply execution and coupling cap type will influence the subjective impression as will associated amplifier, speakers, room, listener's hearing accuity, mood, music played, etc.
A Dyna PAS phono stage could be wired with the same feedback RIAA - the cathode follower would be gone (a good thing maybe)
Conrad-Johnson's PV1 was a fair knockoff IIRC. Other circuits may image diferently. A stripped down Stu Hegeman type based in Citation I and IV, with "anode follower" high level stage could be fun too if one wishies to explore the old ways of the golden age of Hi Fi.
One thing which facinates me - as time moved on towards solid state, designers like Stu Hegeman with his HAPI preamp and Grommes designer Al Hart, did not seem to consdier their solid state work to be inferior to their tube era designs.
tubes do not have a sound by themselves, you have to stick it into a circuit to listen out....
i built a lot of Broskie's CCDA and Aikido, and have listened to the SP3 and the Marantz 7.....Broskie gets my thumbs up, and between the CCDA and the Aikido, the CCDA gets my nod...
unless you drop the tube to the floor from a height, you will hear its distinct sound, "pook" clearly......
i built a lot of Broskie's CCDA and Aikido, and have listened to the SP3 and the Marantz 7.....Broskie gets my thumbs up, and between the CCDA and the Aikido, the CCDA gets my nod...
unless you drop the tube to the floor from a height, you will hear its distinct sound, "pook" clearly......
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Can you give some examples of pro-preamps (so non-consumer pre-amps) that use the EF86 in pentode mode for the MM phono input?
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FYI
pentodes can be noisier than triode cascodes for phono, so some people prefer cascodes
pentodes are more microphonic than triode cascades, hence their use in combo guitar amps by vox was limited to their initial low power models
I’d like an original M7 because it is a piece of history, of course I would not modify it!
And same goes for a Jaguar E-type, I’d love one of those too, the point being you can not compare with a modern car or you simply miss the whole point.
pentodes can be noisier than triode cascodes for phono, so some people prefer cascodes
pentodes are more microphonic than triode cascades, hence their use in combo guitar amps by vox was limited to their initial low power models
I’d like an original M7 because it is a piece of history, of course I would not modify it!
And same goes for a Jaguar E-type, I’d love one of those too, the point being you can not compare with a modern car or you simply miss the whole point.
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See below-
Design I'm currently building is Dynaco ST35. My current design is pentode pre in (6GH8A).. changing to 12DW7(7247), which I understand is half 12AX7 half 12AU7. Have mag pickup phono, so we'll see about lower gain effect. This design touted by some as 'Quietest amp ever'- So of course I have to build it- lol.
Jim
ps. I don't think filaments are connected to gnd as shown- doesn't make sense to me, so I'm deleting that part. If someone thinks they should be, pls let me know.
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Peter is right, the original question was how it sounds.
There is a "cult" in Japan about the Marantz 7.
Australia now makes the ALU-7, "a remarkably modern approximation of the perfect pre-amp, the Marantz 7".
The Uesugi BROS-1 is also a copy of the 7. Not well known outside Japan, Uesugi Brothers have a cult following in Japan for their electronics. The ‘brothers’ were instrumental in running tests on lot of famous Japanese Hi-fi exotica while being employed at Stereo Sound magazine in Japan..
The best clone so far is the Chriskit. This rare preamp has specifications very similar to the Marantz 7, in fact it uses the same valves 6 x ECC83 12AX7 and the same configuration for which if you consult the Marantz 7 data card the Christkit is similar.
Check this link and scroll down and look at the whole page you will see that there is a Marantz 7 and under the Chriskit also the same is connected to a Macintosh
2019?
2000??
There is a "cult" in Japan about the Marantz 7.
Australia now makes the ALU-7, "a remarkably modern approximation of the perfect pre-amp, the Marantz 7".
The Uesugi BROS-1 is also a copy of the 7. Not well known outside Japan, Uesugi Brothers have a cult following in Japan for their electronics. The ‘brothers’ were instrumental in running tests on lot of famous Japanese Hi-fi exotica while being employed at Stereo Sound magazine in Japan..
The best clone so far is the Chriskit. This rare preamp has specifications very similar to the Marantz 7, in fact it uses the same valves 6 x ECC83 12AX7 and the same configuration for which if you consult the Marantz 7 data card the Christkit is similar.
Check this link and scroll down and look at the whole page you will see that there is a Marantz 7 and under the Chriskit also the same is connected to a Macintosh
2019?
2000??
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Marantz valve gear is legendary for a reason, they made some really good stuff. Even Ken Shindo had designs, in the early days, which were inspired by Marantz (although some get defensive at the suggestion).
That's fine, the filament feed winding should close the circuit to ground, if you don't connect it, no current will flow.
Perhaps you could modify the supply from AC to DC with a pair of diodes ...
I had the opportunity to audition an original Marantz 7 in my high efficiency audio system and it sounded good, especially it had the touch of very old radio gear. Sound was dark but lacking some transparency. There is a mix of transparency, real midrange sound (which is almost combined with tubes and old passive parts) and smooth highs that I'm after. The Marantz strength was for sure its midrange. Otherwise nothing special was noticed by me. A good sounding tube gear that lacks some refinement and (especially for me) the wow factor that makes a componend a real stunner. I think its a collectors item, a little overpriced today.
Still I would like to know from you: Can you give some examples of pro-preamps (so non-consumer pre-amps) that use the EF86 in pentode mode for the MM phono input?
His phono sections could be described as refined versions of Marantz 7 but its much improvement been done from him to fine tune the whole pre including complete different line sections (he didn't use ECC83 for outputs).
What he came up first was his phono versions of famous studio tube preamps.
Must have profound knowledge to improve on those, think he did his job well to learn and copy the best.
more off topic:
The 150kOhm / 0.22uF between 1st / 2nd stage cathodes in the ST35 is * positive * feedback, which boosts the gain beyond what the tube's mu/rk/rp would allow.
In this case the gain of this stage w/pos fb is about 40dB (100x) whereas w/o fb it would be just 30dB (30x).
The 150kOhm / 0.22uF between 1st / 2nd stage cathodes in the ST35 is * positive * feedback, which boosts the gain beyond what the tube's mu/rk/rp would allow.
In this case the gain of this stage w/pos fb is about 40dB (100x) whereas w/o fb it would be just 30dB (30x).
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This reveals a lack of understanding by whoever Kato-san is. So you go from ~900 ohm output impedance with an AX7 cathode follower to ~90 ohms with a 6DJ8. That ain't too shabby, but the big difference is that you can run a whole lot more current through the 6DJ8 compared to the 12AX7, and this is incredibly useful, especially if you plan to drive a solid state amp or two.
Can you give some examples of non-consumer preamps that have MM inputs?
There are plenty of pro sound microphone preamps with EF86s in them...
Robert,
there has been an armada of them. But first you'll have to understand, those studio pre tube gear wasn't mostly specialised in phono but in mic input.
Thats why the circuits mostly miss the RIAA encoding network. This could be added, of course, but in original circuit they were mostly general high impedance, high mu amplifiers build to studio standards, not for home consumer gear standards like Marantz.
So we can start with the famous TAB V76, V72
Langevin 103, 117 and many more
WE: same as Langevin but some different amps, too
Klangfilm KL V002 and some more
Maihak B-V41, 42, 72 and many more
Neumann: famous U47
Siemens V77, V78
Telefunken V41a
EMI: REDD 47 (Beatles!)
Westrex: some of the british preamps
Collins: 212 broadcast preamp
Leak and Mullard use EF86 for their famous tube preamps (real phono pre's)
Neumann: WV2
EMT: V54/5
Shindo Labo: Petrus mono, some other models and incarnations
The list is a who-is-who of the finest tube era studio gear, mostly european and german amps. Thats because the pentode was invented in europe in the Netherlands.
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I conclude: You can't give an example of a "pro-preamp" with an EF86 in pentode mode for mm phono input.