How good is the Marantz phono stage?

[WhiteBeard]

Hello everybody!

I'm considering going ahead and ordering a Marantz PM6005 amplifier for my Rega RP1 turntable and Denton Wharfdale speakers.

I also own a Rega Fono A2D that I got together with the turntable. But now that I'm about to buy the Marantz, I was wondering how good the built-in phono stage is on the amplifier?
Anybody has any experience with this amp?

In other words, can I return the Rega Fono (it is still returnable, no charge) and have a cleaner interface with just the Marantz, without loosing audio quality?

Best regards,
Nat

 

[sqlsavior]

Your own evaluation will be far more valuable than someone else's. I would not return it yet...

Edit: I confused it with the Fono MM, which I would definitely save for comparison. The A2D will do something the other two won't, however. Keep it if your computer has no (or poorer) A2D capability.

 

[ETI_5000]

Signal to noise ratio, dB A-weighted, for 5mV input:
Marantz 83, Rega 78; winner Marantz by 5dB

RIAA accuracy, dB, 20Hz-20kHz:
Marantz ±1, Rega not specified(Rega policy for losing sales - don't provide the useful specifications that everyone else provides, so they choose the competitors' products!); winner Marantz for providing
the figure, which Rega haven’t)

Overload, mV:
Marantz 100, Rega 70; winner Marantz by 30mV

Input capacitance, pF:
Marantz not specified, Rega 100pF; Winner Rega. The Rega's capacitance is a good choice for modern MM and MI cartridges, but Marantz want us to guess whether their figure's good (less than 120pF) or bad (over 200pF) for most modern MM/MI cartridges.

My assessment? Neither are the greatest phono stages, but the Marantz is significantly quieter, has a much better overload figure, and doesn’t leave out the RIAA accuracy figure, but spoils its almost perfect record by leaving out one of the most crucial specs in how a cartridge will sound - the input capacitance. Unless you really need the USB output, return the Rega, and keep the Marantz, because on phono it beats the Rega in several crucial areas. Hopefully Marantz designers are clued up enough to provide a usefully low input capacitance, even if their manual writers don't provide it.

 

[Jim Creek]

I've owned my Marantz PM8004 for a couple of years. The phono stage is made of discrete circuity (no ICs) . It is quiet, REALLY quiet. The PM6005 is no doubt similar.

Here's a review of the amp in THE ABSOLUTE SOUND. The review of the phono stage is glowing.

http://sales.dmh-global.com/Shared ...duct Reviews/Absolute Sound_PM8004 review.pdf

 

[lini]

Jim: I wouldn't rely on that. Unfortunately I couldn't find a schematic/service manual on a quick search to verify, but I wouldn't be surprised, if the 6005 only sported "the usual op-amp-based implementation" around a comparatively cheap JRC/NJR op-amp type, 'cause that would nowadays seem more usual for a Marantz in that budget range...

Greetings from Munich!

Manfred / lini

 

[ETI_5000]

The Marantz PM6005 and PM8004 have entirely different phono stages, and I can say that without even looking at the circuits (which I can’t find, either). The PM8004 justifies its extra cost by having closer adherence to the RIAA standard than the PM6005 (±0.5dB versus ±1.0dB), and a quieter phono stage (87dB versus 83dB). So they almost certainly don’t share exactly the same phono preamp stage, because of the different specs.

By the way, I wouldn’t hesitate to use op-amps if I was designing a cost-no-object phono preamp, rather than entirely discrete components. Good op-amp designs are very low in noise and distortion. So saying something uses fully discrete circuitry means nothing – it might appeal to snobs, but it will probably be more expensive as a result, and won’t necessarily produce better performance than a good op-amp design.

In fact, a relatively low power (40W RMS per channel) older Proton receiver owned by another member, that I was looking at a few days ago, beat the PM8004’s ‘fully discrete’ phono stage noise figures by 5dB, despite using op-amps. Admittedly it did use expensive ultra-low noise transistors at the phono inputs to reduce noise, similar to some very expensive amps, but the Proton designers had done an excellent job and it was much quieter than the Marantz fully discrete circuit phono stage, as well as having a more accurate RIAA response (±0.2dB)! So despite using op-amps rather than discrete components, it was a significantly better phono stage, even if the un-educated snob reviewer thinks discrete components are better. A little knowledge is better than snobbery when designing good electronics….

That's not to say that the Marantz amps don't have decent phono stages, by the way - just that another (excellent) design was better.

 

[Jim Creek]

In fact, a relatively low power (40W RMS per channel) older Proton receiver owned by another member, that I was looking at a few days ago, beat the PM8004’s ‘fully discrete’ phono stage noise figures by 5dB, despite using op-amps. Admittedly it did use expensive ultra-low noise transistors at the phono inputs to reduce noise, similar to some very expensive amps, but the Proton designers had done an excellent job and it was much quieter than the Marantz fully discrete circuit phono stage, as well as having a more accurate RIAA response (±0.2dB)! So despite using op-amps rather than discrete components, it was a significantly better phono stage, even if the un-educated snob reviewer thinks discrete components are better. A little knowledge is better than snobbery when designing good electronics….

That's not to say that the Marantz amps don't have decent phono stages, by the way - just that another (excellent) design was better.

Wow!
You must have some pretty sophisticated testing equipment.

 

[lini]

Don: Just fyi, in the PM7000/8000 Marantz also used an MM section with a pair of 2SK369s per channel in front of an NJM2214 - quite a fair implementation, unless one has the European variant, which has an input capacity of 1150 pF instead of 150 pF on the other variants and hence needs to be modified in order to actually be useful as an MM section. In the newer models the European variants don't have that much excess capacity for passing CE EMI regulations anymore, but still tend to be a bit on the high side...

Greetings from Munich!

Manfred / lini

 

[ETI_5000]

Wow!
You must have some pretty sophisticated testing equipment.

Actually, I was quoting the manufacturer's specifications. They are usually quite believable when reputable manufacturers use a certain standard - in this case the IHF A-weighted standard for phono preamps. After a look at the Proton's phono preamp circuit, which used two 2SC2602 transistors in front of an M5219C op-amp for the MM preamp, and switched in extra 2SC2602's in front of the MM preamp to provide extra gain for LOMC's, I can believe their specs, as they are of a similar order to specs from manufacturers such as Pioneer and Sony which used similar circuit configurations. An electronics magazine in Australia which used a similar design in several DIY projects from the 1980's and early-90's also had similar measured specs.

That's not to say that I believe all specs quoted - some supply specs which are quite unbelievable, based on the simple circuits they use, but they usually aren't sold by hi-fi shops.

 

[ETI_5000]

Don: Just fyi, in the PM7000/8000 Marantz also used an MM section with a pair of 2SK369s per channel in front of an NJM2214 - quite a fair implementation, unless one has the European variant, which has an input capacity of 1150 pF instead of 150 pF on the other variants and hence needs to be modified in order to actually be useful as an MM section. In the newer models the European variants don't have that much excess capacity for passing CE EMI regulations anymore, but still tend to be a bit on the high side.../QUOTE]

Yes, that's a good general phono circuit. However, I can't understand why they've messed that one version of the phono board up with super-high capacitance, when they put those two capacitors in! <<<Europeans Very strange.

 

[lini]

Don: Well, Marantz wasn't/isn't the only company to go that easy way for achieving CE compliance. For example, the Teac AG-790 receiver has 820 pF on its MM input - and that combined with an input impedance of 22 kOhm. But that's a very basic MM section anyway - so for owners of that Teac I'd rather suggest to use an Art DJPreII instead. Whereas in case of the Marantz PM7000/8000/7200 I'd suggest to mod the existing MM section, 'cause an external replacement on that quality level would cost roundabout 150 US$ or Euro, while the mod is only a couple of Euro and not much work...

Greetings from Munich!

Manfred / lini

 

[Sttaf]

Don: Well, Marantz wasn't/isn't the only company to go that easy way for achieving CE compliance. For example, the Teac AG-790 receiver has 820 pF on its MM input - and that combined with an input impedance of 22 kOhm. But that's a very basic MM section anyway - so for owners of that Teac I'd rather suggest to use an Art DJPreII instead. Whereas in case of the Marantz PM7000/8000/7200 I'd suggest to mod the existing MM section, 'cause an external replacement on that quality level would cost roundabout 150 US$ or Euro, while the mod is only a couple of Euro and not much work...

Greetings from Munich!

Manfred / lini

Lini,
I’ve got a Nagaoka PM 500 mounted on a Thorens TD 320 and actually when connected to my PM 7000 (1999 european version) it sounds metallic...medium on the higher frequency too strong...
When you say to modify, what do you suggest to do exactly? To Remove one of the 2 capacitors of 680pF and 470pF (maybe the 680pF)? I add a snapshot of Pm7000 service manual.

Thank you in advance for your reply!

 

[lini]

(...) To Remove one of the 2 capacitors of 680pF and 470pF (maybe the 680pF)?

Both, actually - i.e., you'd best remove both 2253/2254 and 2255/2256 and then replace the latter with two new caps between 100 and 150 pF.

Greetings from Munich!

Manfred / lini

 

[Sttaf]

Both, actually - i.e., you'd best remove both 2253/2254 and 2255/2256 and then replace the latter with two new caps between 100 and 150 pF.

Greetings from Munich!

Manfred / lini

Manfred,
Thank you very much for your useful suggestions: I removed the 4 capacitors in my Marantz PM 7000 and replaced them with two 100 pF ones and the result was the best I could have: finally my nagaoka MP 500 sounds as it deserves, with no more that “metallic” feeling, equilibrated medium frequencies and sharp but not fatiguing high frequencies. It seems I’ve changed cartridge!

Happy Easter!

 

[lini]

finally my nagaoka PM 500 sounds as it deserves

Nice to read, that the modification was successful.

Greetings from Munich & happy Easter to you, too!

Manfred / lini

 

[Engineria]

I know it's an old post, but I have an old Marantz 7200 amp.

The main amplifier is dead and sadly only lasted about 2 years after re-cap.

I am planning on harvesting the phono pre-amp circuit board though. I have the circuit schematics and it's easy to re-house it in another case with a small psu and some connectors.

I will probably upgrade the op-amp. The NJM 2114s (of which there are two in the amp) are not particularly quiet, when I replaced one in the volume/tone control board, the background noise disappeared and I couldn't tell if the amp was on, which was pretty scarey! Though this may be due to the PSRR rather than noise.

Does anyone have some suggestions for op-amps, or particular input capacitors?