Pre-Amp Face Off: Crown IC150A, Accuphase C200 and Kenwood 700C

[PeterFCassidy]

Which one wins in a race determined by the quality of the phone pres?

Peter

 

[EchoWars]

Phone pres? Translation pls...

 

[yamahammer]

:ntwrthy: :ntwrthy: I think he means phono preamp

 

[PeterFCassidy]

Phono pres - Phonographic Pre-amplifiers

Sorry, shouldn't type while talking on the phone and drinking tea.

Phonographic pre-amplifiers is what I meant by Phone pres. Heard good things about all of these for the quality of their phonographic pre-amps.

Phone pres? Translation pls...

Peter

 

[Blue Shadow]

Wow, tea, that is not too strong, stay away from the egg nog!!

The Crown is known to be a harsh sounding pre. So I doubt it would be the best of these three.

 

[bully]

I think I would choose the Accuphase--and I believe it has Kenwood affiliation, as Kensonic was started by former Kenwood guys.
The 700C certainly has its proponents, too.

 

[theophile]

If I recall EW posted previously that in his opinion the best Kenwood phono stage is in the KA 9100.

 

[motorstereo]

With the money you made from selling your vaunted g8000 hell I'd buy all 3.

 

[EchoWars]

There's nothing wrong with the phono on the 700C, but truthfully I like FET input stages for phono, and the 700C has bipolar transistors. Still sounds quite fine. Might have to do with the +/-50V supplies, which borders on extreme.

I really like the phono stage on the KA-9100.

As far as the other amps you mention, I can't really comment, as I do not know them well enough. I will say that there is a lot more interaction between phono stages and MM cartridges than many would lead you to believe, which makes comparisons difficult and sometimes unfair. Best way to avoid the cart-phono stage interaction mess is to go to a low-impedence MC cart, and an outboard phono amp.

 

[PeterFCassidy]

The vinyl is more of a black art than I'd imagined

Gosh, you mean I will have difficulties getting a good result just because I am using a MM cartridge? I like the 681 EEE but I didn't imagine its very design would complicate things. Is the interaction of which you speak related to radiant energy from the cartridge itself? (I had one technician shield the interior of a cartridge shuttle with copper but I think that was to keep motor noise from being picked up by the cartridge.) What do you like in outboard phono amps? -PFC

There's nothing wrong with the phono on the 700C, but truthfully I like FET input stages for phono, and the 700C has bipolar transistors. Still sounds quite fine. Might have to do with the +/-50V supplies, which borders on extreme.

I really like the phono stage on the KA-9100.

As far as the other amps you mention, I can't really comment, as I do not know them well enough. I will say that there is a lot more interaction between phono stages and MM cartridges than many would lead you to believe, which makes comparisons difficult and sometimes unfair. Best way to avoid the cart-phono stage interaction mess is to go to a low-impedence MC cart, and an outboard phono amp.

 

[ron-c]

Accuphase of course.

Thanks,
Ron-C

 

[EchoWars]

Interactions are due to the high-impedance nature of the MM cartridges, and the high-impedance of the MM phono stages. It's just the nature of the beast. Here's what Dr. Leach has to say about it:

The output impedance of conventional magnetic cartridges is typically 2 kohm to 3 kohm resistance in series with 500 to 1000 mH inductance. This very large inductance causes the output impedance at high frequencies to become large. The input impedance to preamplifiers has a capacitive component at high frequencies. In combination with the inductive output impedance of the cartridge, this can cause a loss of high frequencies. Depending on the damping of the circuit, a resonant peak can exist in the high frequencies just below the rolloff frequency. This is one of the reasons that different cartridge and preamplifier combinations can sound so different.

One of the methods of minimizing cartridge preamplifier impedance interactions is to use use a cartridge with a very low output impedance. Such a cartridge is able to drive a capacitive load with no impedance interactions. A moving coil cartridge has this characteristic. Unfortunately, the output voltage is too low to drive a phono preamplifier directly.

Whereupon he proceeds to go into some designs of phono input stages. Link.

 

[PeterFCassidy]

Great Technical Write-Up and Ripping Yarn

Georgia Tech is an amazing institution. Their CS guys are also a gift to the art.
What a story about the fellow's circuit design being lifted by pirate audio companies! Thankest. -pfc

Interactions are due to the high-impedance nature of the MM cartridges, and the high-impedance of the MM phono stages. It's just the nature of the beast. Here's what Dr. Leach has to say about it:Whereupon he proceeds to go into some designs of phono input stages. Link.

 

[Jay Pemberton]

I have both an IC 150A and a Dynaco PAS 2 tube preamp. I changed the op amps from those old TL071s to Burr-Brown OPA134s (as I'm too skint to go with OPA627s). Much better, but there's still the shortcomings due to the old electrolytic caps in the 150's phono stage. That old Dynaco's phono stage is still superior (less background grunge; it was better-sounding than the 150 even with it's original, tired Pyramid coupling caps, but I replaced them several years ago with Sprague 'orange drops'). I would love to be able to afford such as Black Gate caps in all the right values, non-polarised, to replace all the polarised caps in the 150, and THEN listen to it.

Currently I'm using the phono stage of the PAS into the line section of the 150....

 

[ARRAY]

From what I understand of this pre-amp, it is a collectible model which specs out extremely well on paper but sounds like sheist warmed over. Perhaps it is collectible because of its tweakability.

 

[Brian]

Of those you mention, the Accuphase would get my vote but. there is better out there depending on your buget. The Crown isn't worth consideration at any price. It was as bad a preamp as I have ever experienced save thr Dyna PAT 4.