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Old 10th April 2003, 12:58 AM   #21
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Then, going back to my second post in this thread, Frank..

Which would you choose?

-Maz
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Old 10th April 2003, 02:31 AM   #22
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Quote:
Originally posted by Saurav

pedroskova said:

" Mr. Joppa designed the RIAA network to accept the ccs with no changes(the riaa curve is barely effected)."

I'm confused. Are the two statements talking about different things? If not, then it looks like the RIAA circuit was designed keeping a future CCS in mind (assuming it is possible to design that way), right? Just trying to understand if the two of you are talking about the same thing or not.
I don't represent Mr. Joppa or Bottlehead, but yes, this circuit was designed with a ccs load in mind. From what I understand, the grid resistor of the second stage ameliorates any changes in the first stage's source impedance. If I remember correctly, the addition of the ccs actually improves the riaa curve...which makes sense, if one is aware of the tweaking habits of Bottlehead customers. This doesn't mean that the stock unit is inaccurate(it's within 2% of the ideal curve), it only means that the ccs's results are more accurate.

...anybody with experience with the "Bottlehead philosophy" will understand.

Others won't.
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Old 10th April 2003, 02:59 AM   #23
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Quote:
From what I understand, the grid resistor of the second stage ameliorates any changes in the first stage's source impedance.
Can you explain this? Normally. the source impednce of the first stage forms the R part of an RC pole. It's unclear to me how the load resistor can "ameliorate" the change in source R. The way I'm reading what you're saying is that they design for best RIAA accuracy with a CCS and then accept the error when a simple plate load resistor is substituted.
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Old 10th April 2003, 03:01 AM   #24
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Default Choices, If Must Be.

Hi,

Quote:
Which would you choose?
The Hagerman.
And for the same justified reasons SY prefered it.
I'd rather perfect a circuit I'd have a view on than talking about something I don't know at all.

If you have a preference for a 6DJ8 based phono stage, no problem, you can have plenty of those too.

If the 12AX7A has a "raison d'etre" it is here and little place else assuming it is being fed by a MM cartridge and NOT an MC.

All this assuming you want to stick to either one, if you were to design from scratch my response would be a different one altogether.

Cheers,
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Old 10th April 2003, 03:11 AM   #25
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Quote:
Originally posted by SY

The way I'm reading what you're saying is that they design for best RIAA accuracy with a CCS and then accept the error when a simple plate load resistor is substituted.
They designed for both in concert. You're in Napa Valley, why don't you post on their forum asking to hear it? Someone nearby is sure to invite you into their abode: then it won't be theoretical.

oops, that wouldn't be fun.
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Old 10th April 2003, 03:21 AM   #26
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Hi,

Quote:
From what I understand, the grid resistor of the second stage ameliorates any changes in the first stage's source impedance. If I remember correctly, the addition of the ccs actually improves the riaa curve...which makes sense,
Well, I don't know it all but this I know: you either phrase it very badly or you don't get it at all.

No big deal as long as you understand that:

No grid resistor (assuming a gridstopper here) is going to "ameriolate anything but HF stability and... the addition of a CCS is going to influence the RIAA curve one way or another, be that designed in from the start or not, some customer is going to end up just a little disappointed...remember I said it was a "breaker"?

I often say that designing a phonopreamp is much harder than a half decent amp...

Guess you start to see why?
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Old 10th April 2003, 03:22 AM   #27
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This isn't a "listening" thing, we're talking about an objective measurement (RIAA eq accuracy). In this case, I'd want to stick my precision inverse RIAA on the input and check the changes in EQ when switching between the two circuits. Since I'm not out to buy one of these (I like my phono preamp just fine, thank you), I'm unlikely to take the time to do such. But in absence of an explanation, data from the guy selling the product, or at the minimum, a schematic, I'd still recommend that Magnetmaz look elsewhere.
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Old 10th April 2003, 03:28 AM   #28
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Default GAME OVER.

Hi,

Quote:
They designed for both in concert.
Nah,nah...that would never work...which doesn't mean they didn't....

Either way is wrong but this is a budget thing isn't it?

Phewww,
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Old 10th April 2003, 04:19 AM   #29
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I give up. I'll never win a nuts and bolts argument...especially when I've never seen the schematic.

Having said that, I'll put my money on horses that I've seen in action...and, given the intial question of this thread, I'll stick to my guns.

Hagerman(sp?)- supply your own chassis, but never think of improving the circuit(PC board).

Bottlehead - build this(probably as good or better that the Hagerman circuit)...and here's an improvement...and there's an improvement...

I know that this is meaningless to the ivorytowerwinesippingwags, but in a time where high fidelity equals MP3(not to be confused with E=MC^2), I think that it's refreshing to see kits made in the "Bottlehead way", and further...oh, never mind

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Old 10th April 2003, 04:20 AM   #30
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I appreciate everyone's opinion.


In my particular case, the reason it falls down to either one of the two i mentioned at the beginning ( or any other fitting the following criteria that you may be able to suggest )

1) I have a tube based system so far ( 300b amp and foreplay), and i would like to continue the trend with a tube based phono stage. I've seen a handful of all solid state phono stages and they dont inspire me. I'm somewhat Anti-solid-state right now...stuck in a tube obsession with a need to create something else utilizing the medium.

2) I've only had 6 months experience in reading, and not much hands on building experience. (really, just the foreplay ) I certainly couldn't design my own. I'm still in the beginning stages of this hobby and I don't really have the knowledge to deviate from a project with somewhat detailed instructions. ( the instructions for both Seduction and Cornet are in depth and designed for someone of my level ).

3) Budget : both cost around $250. I couldn't spend much more than this right now being unemployed.


If you can think of anything else that falls within these constraints, let me know.

-Maz
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