AudioNervosa

Systemic Development => Amplification and Preamplification => Topic started by: rollo on January 04, 2019, 07:45:15 AM

Title: Do We Need Linestages ????
Post by: rollo on January 04, 2019, 07:45:15 AM
   Depends. If playing LPs then a linestage or preamp/phono is required. However sometimes for digital a passive is a very good choice. It may not have the body and weight of a good active however offers more transparency and less noise.
   There are parameters for passive use such as; Digital output must be 2V minimum, preferably 3V or more. The amp should have an input sensitivity of [1] or less for optimal results. More than [1] is OK just need more volume.
    A passive IMO is more useful with SET amps and a high output DAC or CD player. To date the Stevens & Billington trannie [ copper ] based passives and th Dave Slagle Autoformers are the ones to have. Those are NOT thin sounding which is a trait of resistor or LED based  passives.
    Just another way to bring us the music.


charles
Title: Re: Do We Need Linestages ????
Post by: Nick B on January 04, 2019, 09:06:22 AM
   Depends. If playing LPs then a linestage or preamp/phono is required. However sometimes for digital a passive is a very good choice. It may not have the body and weight of a good active however offers more transparency and less noise.
   There are parameters for passive use such as; Digital output must be 2V minimum, preferably 3V or more. The amp should have an input sensitivity of [1] or less for optimal results. More than [1] is OK just need more volume.
    A passive IMO is more useful with SET amps and a high output DAC or CD player. To date the Stevens & Billington trannie [ copper ] based passives and th Dave Slagle Autoformers are the ones to have. Those are NOT thin sounding which is a trait of resistor or LED based  passives.
    Just another way to bring us the music.


charles

Charles,
I’ve never used a passive in my system. I’ve heard of the Slagle and S & B, but I wonder  if you have
any experience with the Tortuga? Our forum member Gary has one and likes it.
Nick
Title: Re: Do We Need Linestages ????
Post by: steve on January 04, 2019, 09:48:02 AM
It depends upon how good of sound quality one wishes, and the expense. How much is one willing to compromise?
The problem now is that no one has the knowledge or is capable of doing it, so compromise is the deal of today.

First, a certain amount of gain is needed in a system. Too low of gain and the volume control has to be turned 
all the way up. Too much gain and noise, hum, more gain stages are used than needed, with each gain stage (or buffer stage) deteriorating the sonics.

A question to ask; how good is an analog gain stage in a cd player? I have not heard one yet that was all that great. Synergy will only go so far.

What about an integrated amp, one with the preamplifier included in the basic amplifier? And then using an external passive volume control. Well, one runs into real problems with capacitance, resistance, resonance problems etc, all which take away from the quality of the music. This includes resistance and transformer types. LED types are included.

Integrateds have the problem of musical feedback through the power supply as well.

Another problem with integrateds is how is it listening tested for accuracy/naturalness, simply auditioning? That is not going to cut it. See saw? Well, that is better than nothing, but one is expending tons of money on different purchases.
Look at everything for sale on the forums. That is good for a laugh, but too sad to do so.

Let's take separates. The preamplifier can be specially listening tested for accuracy/naturalness due to the lower gain of each. The amplifier can also be, but who knows how, or is willing to do so? The 28db gain amplifier pretty much excludes itself because of its integrated, way too high gain nature.

Why all the companies/designers who don't have the know how to provide the best sonics? Why are they still in business? If only the competent were in business, they would have more business, since the amateurs would be gone, and the customer would have a better product.

I guess the conclusion is to do the see saw principle and hopefully get a loaner.

cheers

steve
Title: Re: Do We Need Linestages ????
Post by: Nick B on January 04, 2019, 12:54:35 PM
It depends upon how good of sound quality one wishes, and the expense. How much is one willing to compromise?
The problem now is that no one has the knowledge or is capable of doing it, so compromise is the deal of today.

First, a certain amount of gain is needed in a system. Too low of gain and the volume control has to be turned 
all the way up. Too much gain and noise, hum, more gain stages are used than needed, with each gain stage (or buffer stage) deteriorating the sonics.

A question to ask; how good is an analog gain stage in a cd player? I have not heard one yet that was all that great. Synergy will only go so far.

What about an integrated amp, one with the preamplifier included in the basic amplifier? And then using an external passive volume control. Well, one runs into real problems with capacitance, resistance, resonance problems etc, all which take away from the quality of the music. This includes resistance and transformer types. LED types are included.

Integrateds have the problem of musical feedback through the power supply as well.

Another problem with integrateds is how is it listening tested for accuracy/naturalness, simply auditioning? That is not going to cut it. See saw? Well, that is better than nothing, but one is expending tons of money on different purchases.
Look at everything for sale on the forums. That is good for a laugh, but too sad to do so.

Let's take separates. The preamplifier can be specially listening tested for accuracy/naturalness due to the lower gain of each. The amplifier can also be, but who knows how, or is willing to do so? The 28db gain amplifier pretty much excludes itself because of its integrated, way too high gain nature.

Why all the companies/designers who don't have the know how to provide the best sonics? Why are they still in business? If only the competent were in business, they would have more business, since the amateurs would be gone, and the customer would have a better product.

I guess the conclusion is to do the see saw principle and hopefully get a loaner.

cheers

steve

Steve,
As you only manufacture ic’s nowadays, have you heard other manufacturers’ amps, integrateds etc and, if so, can you render an opinion on which companies produce exceptional sounding products?
Nick
Title: Re: Do We Need Linestages ????
Post by: HAL on January 04, 2019, 03:57:41 PM
Or a phono stage directly into a balanced input ADC to the dspMusik running at 24bit/192KHz like my system. 

Adjustable gain in 6dB steps over an 18dB range for both the ADC and DAC with the 32 bit DAC 32bit volume controls doing 0.5dB steps, driving the amps directly and doing the digital crossover. 

Works for me.



 
Title: Re: Do We Need Linestages ????
Post by: tmazz on January 05, 2019, 07:05:28 AM

Why all the companies/designers who don't have the know how to provide the best sonics? Why are they still in business? If only the competent were in business, they would have more business, since the amateurs would be gone, and the customer would have a better product.


Steve that is spoken like a true engineer (I should know, I are one too.  :) ). You are equating success in the market place with designing the best product. Unfortunately this is not the case. Unfortunately success in the marketplace is not based on who designs the best or builds the best , it is determined by who sells the best. In most cases the reality is much to the chagrin of us engineers, most of the time in the retail world, success in the marketplace is more dependent on the marketing department than the engineering department. You can have the best product in the world, but if the word does not get out to the customer base nobody will know about it. This is especially important in this hobby in that a company needs to know which asses to kiss in order to get reviews, endorsements and product placement in the right places. Also marketing is more than just selling. A good marketing department will also guide the company in what types of product will sell in the marketplace. We here would all like to think that it is make the best sounding products and that's it, but there is much more to it than that. Especially in a high priced, luxury product market like high end audio there are many other factors that drive purchase decisions besides SQ.  Not the least of these is image. This can take on the form of brand reputation. How many people spend $350k on a sports car because they like the way it drives. I would postulate that a large percentage of those sales are driven by the desire to be able to in front of your friends say to the valet at the country club "Son, bring around my Ferrari."  Image can also extend to product decisions. In our hobby a phono cartridge can easily and safely be packaged in a simple cardboard or plastic box. But many high end cartridges  come in fancy polished wooden cases than can cost more themselves than many good quality cartridges simply because the marketing folks insist that you cannot hand a plastic box to a customer who just plunked down $10K for a cartridge (or a cable), no matter how good the product is. And to a large extent they are right.

I could go on, but the bottom line is that retail companies live and die not based on who has the best products, but rather who makes the most sales. And retails sales are dependent on many factors other than the product performance. It may not make sense to us as engineers, but that is the way it is with the rest of the world.

Wow, I just had a thought - Imagine if the world was made up entirely of engineers, our entire civilization would grind to a total halt as everyone sat around discussing every possible what-if and never made a single decision. (https://groups.tapatalk-cdn.com/smilies/1733/1534579953.0988-smiley.gif)

I guess that is the most important function of the marketing department, they give us engineers deadlines.  :duh
Title: Re: Do We Need Linestages ????
Post by: Triode Pete on January 05, 2019, 08:28:18 AM

Why all the companies/designers who don't have the know how to provide the best sonics? Why are they still in business? If only the competent were in business, they would have more business, since the amateurs would be gone, and the customer would have a better product.


Steve that is spoken like a true engineer (I should know, I are one too.  :) ). You are equating success in the market place with designing the best product. Unfortunately this is not the case. Unfortunately success in the marketplace is not based on who designs the best or builds the best , it is determined by who sells the best. In most cases the reality is much to the chagrin of us engineers, most of the time in the retail world, success in the marketplace is more dependent on the marketing department than the engineering department. You can have the best product in the world, but if the word does not get out to the customer base nobody will know about it. This is especially important in this hobby in that a company needs to know which asses to kiss in order to get reviews, endorsements and product placement in the right places. Also marketing is more than just selling. A good marketing department will also guide the company in what types of product will sell in the marketplace. We here would all like to think that it is make the best sounding products and that's it, but there is much more to it than that. Especially in a high priced, luxury product market like high end audio there are many other factors that drive purchase decisions besides SQ.  Not the least of these is image. This can take on the form of brand reputation. How many people spend $350k on a sports car because they like the way it drives. I would postulate that a large percentage of those sales are driven by the desire to be able to in front of your friends say to the valet at the country club "Son, bring around my Ferrari."  Image can also extend to product decisions. In our hobby a phono cartridge can easily and safely be packaged in a simple cardboard or plastic box. But many high end cartridges  come in fancy polished wooden cases than can cost more themselves than many good quality cartridges simply because the marketing folks insist that you cannot hand a plastic box to a customer who just plunked down $10K for a cartridge (or a cable), no matter how good the product is. And to a large extent they are right.

I could go on, but the bottom line is that retail companies live and die not based on who has the best products, but rather who makes the most sales. And retails sales are dependent on many factors other than the product performance. It may not make sense to us as engineers, but that is the way it is with the rest of the world.

Wow, I just had a thought - Imagine if the world was made up entirely of engineers, our entire civilization would grind to a total halt as everyone sat around discussing every possible what-if and never made a single decision. (https://groups.tapatalk-cdn.com/smilies/1733/1534579953.0988-smiley.gif)

I guess that is the most important function of the marketing department, they give us engineers deadlines.  :duh

Spoken like a true ENGINERD! LOL!  :rofl:
Title: Re: Do We Need Linestages ????
Post by: rollo on January 05, 2019, 11:34:14 AM
  Interesting replies so far. Steve right about most analog sections for DAC. Unless one pays for it. Ask Dan at Modright that is what they do. Replace the analog section.


charles
Title: Re: Do We Need Linestages ????
Post by: steve on January 05, 2019, 06:22:01 PM

Why all the companies/designers who don't have the know how to provide the best sonics? Why are they still in business? If only the competent were in business, they would have more business, since the amateurs would be gone, and the customer would have a better product.


Steve that is spoken like a true engineer (I should know, I are one too.  :) ). You are equating success in the market place with designing the best product. Unfortunately this is not the case.

Never meant that at all, I was not clear, my bad T. With hundreds of so called designers/engineers, each selling X components a year, that mounts to thousands of components that competent designers and manufacturers could be manufacturing and selling, staying in business, and giving the customer better product.

In fact, I hate the marketers because they use the fancy talk to push product while demonizing competent companies.
I hope I am more clear this time, T. :)

Quote
Unfortunately success in the marketplace is not based on who designs the best or builds the best , it is determined by who sells the best. In most cases the reality is much to the chagrin of us engineers, most of the time in the retail world, success in the marketplace is more dependent on the marketing department than the engineering department. You can have the best product in the world, but if the word does not get out to the customer base nobody will know about it. This is especially important in this hobby in that a company needs to know which asses to kiss in order to get reviews, endorsements and product placement in the right places.

I guess that is the most important function of the marketing department, they give us engineers deadlines.  :duh
[/quote]

Isn't that the truth. Marketing seems to almost always win over designing. I agree and wish I had expressed my post clearer. Even with the competent designers, there is model after model claiming closer to accurate, yet sonic differences. But at least the customer should obtain better product. Cross your fingers.

cheers
Title: Re: Do We Need Linestages ????
Post by: steve on January 05, 2019, 06:29:45 PM
It depends upon how good of sound quality one wishes, and the expense. How much is one willing to compromise?
The problem now is that no one has the knowledge or is capable of doing it, so compromise is the deal of today.

First, a certain amount of gain is needed in a system. Too low of gain and the volume control has to be turned 
all the way up. Too much gain and noise, hum, more gain stages are used than needed, with each gain stage (or buffer stage) deteriorating the sonics.

A question to ask; how good is an analog gain stage in a cd player? I have not heard one yet that was all that great. Synergy will only go so far.

What about an integrated amp, one with the preamplifier included in the basic amplifier? And then using an external passive volume control. Well, one runs into real problems with capacitance, resistance, resonance problems etc, all which take away from the quality of the music. This includes resistance and transformer types. LED types are included.

Integrateds have the problem of musical feedback through the power supply as well.

Another problem with integrateds is how is it listening tested for accuracy/naturalness, simply auditioning? That is not going to cut it. See saw? Well, that is better than nothing, but one is expending tons of money on different purchases.
Look at everything for sale on the forums. That is good for a laugh, but too sad to do so.

Let's take separates. The preamplifier can be specially listening tested for accuracy/naturalness due to the lower gain of each. The amplifier can also be, but who knows how, or is willing to do so? The 28db gain amplifier pretty much excludes itself because of its integrated, way too high gain nature.

Why all the companies/designers who don't have the know how to provide the best sonics? Why are they still in business? If only the competent were in business, they would have more business, since the amateurs would be gone, and the customer would have a better product.

I guess the conclusion is to do the see saw principle and hopefully get loaners.

cheers

steve

Steve,
As you only manufacture ic’s nowadays, have you heard other manufacturers’ amps, integrateds etc and, if so, can you render an opinion on which companies produce exceptional sounding products?
Nick

The deHavilland Ultraverve is pretty darn excellent, years ago tested, with the NOS tubes as far as preamplifiers. At least one audio show, their system was excellent for the setup, so I don't know about her amplifiers because of room and speakers used. But the Ultraverve is just super. (Don't know the NOS brands used though, sorry.) Herron was pretty darn good as well.

Amplifiers, the Pass 30.5 and Belles Reference 350 were fabulous. Make sure the Belles says "reference 350", not just 350. Don't know about lately brands.

I would definitely recommend these Nick.

Cheers

steve

Title: Re: Do We Need Linestages ????
Post by: Nick B on January 05, 2019, 08:53:25 PM
It depends upon how good of sound quality one wishes, and the expense. How much is one willing to compromise?
The problem now is that no one has the knowledge or is capable of doing it, so compromise is the deal of today.

First, a certain amount of gain is needed in a system. Too low of gain and the volume control has to be turned 
all the way up. Too much gain and noise, hum, more gain stages are used than needed, with each gain stage (or buffer stage) deteriorating the sonics.

A question to ask; how good is an analog gain stage in a cd player? I have not heard one yet that was all that great. Synergy will only go so far.

What about an integrated amp, one with the preamplifier included in the basic amplifier? And then using an external passive volume control. Well, one runs into real problems with capacitance, resistance, resonance problems etc, all which take away from the quality of the music. This includes resistance and transformer types. LED types are included.

Integrateds have the problem of musical feedback through the power supply as well.

Another problem with integrateds is how is it listening tested for accuracy/naturalness, simply auditioning? That is not going to cut it. See saw? Well, that is better than nothing, but one is expending tons of money on different purchases.
Look at everything for sale on the forums. That is good for a laugh, but too sad to do so.

Let's take separates. The preamplifier can be specially listening tested for accuracy/naturalness due to the lower gain of each. The amplifier can also be, but who knows how, or is willing to do so? The 28db gain amplifier pretty much excludes itself because of its integrated, way too high gain nature.

Why all the companies/designers who don't have the know how to provide the best sonics? Why are they still in business? If only the competent were in business, they would have more business, since the amateurs would be gone, and the customer would have a better product.

I guess the conclusion is to do the see saw principle and hopefully get loaners.

cheers

steve

Steve,
As you only manufacture ic’s nowadays, have you heard other manufacturers’ amps, integrateds etc and, if so, can you render an opinion on which companies produce exceptional sounding products?
Nick

The deHavilland Ultraverve is pretty darn excellent, years ago tested, with the NOS tubes as far as preamplifiers. At least one audio show, their system was excellent for the setup, so I don't know about her amplifiers because of room and speakers used. But the Ultraverve is just super. (Don't know the NOS brands used though, sorry.) Herron was pretty darn good as well.

Amplifiers, the Pass 30.5 and Belles Reference 350 were fabulous. Make sure the Belles says "reference 350", not just 350. Don't know about lately brands.

I would definitely recommend these Nick.

Cheers

steve

Thanks, Steve!
Title: Re: Do We Need Linestages ????
Post by: steve on February 15, 2019, 09:24:40 AM

Why all the companies/designers who don't have the know how to provide the best sonics? Why are they still in business? If only the competent were in business, they would have more business, since the amateurs would be gone, and the customer would have a better product.


Steve that is spoken like a true engineer (I should know, I are one too.  :) ). You are equating success in the market place with designing the best product. Unfortunately this is not the case. Unfortunately success in the marketplace is not based on who designs the best or builds the best , it is determined by who sells the best. In most cases the reality is much to the chagrin of us engineers, most of the time in the retail world, success in the marketplace is more dependent on the marketing department than the engineering department. You can have the best product in the world, but if the word does not get out to the customer base nobody will know about it. This is especially important in this hobby in that a company needs to know which asses to kiss in order to get reviews, endorsements and product placement in the right places. Also marketing is more than just selling. A good marketing department will also guide the company in what types of product will sell in the marketplace. We here would all like to think that it is make the best sounding products and that's it, but there is much more to it than that. Especially in a high priced, luxury product market like high end audio there are many other factors that drive purchase decisions besides SQ.  Not the least of these is image. This can take on the form of brand reputation. How many people spend $350k on a sports car because they like the way it drives. I would postulate that a large percentage of those sales are driven by the desire to be able to in front of your friends say to the valet at the country club "Son, bring around my Ferrari."  Image can also extend to product decisions. In our hobby a phono cartridge can easily and safely be packaged in a simple cardboard or plastic box. But many high end cartridges  come in fancy polished wooden cases than can cost more themselves than many good quality cartridges simply because the marketing folks insist that you cannot hand a plastic box to a customer who just plunked down $10K for a cartridge (or a cable), no matter how good the product is. And to a large extent they are right.

I could go on, but the bottom line is that retail companies live and die not based on who has the best products, but rather who makes the most sales. And retails sales are dependent on many factors other than the product performance. It may not make sense to us as engineers, but that is the way it is with the rest of the world.

Wow, I just had a thought - Imagine if the world was made up entirely of engineers, our entire civilization would grind to a total halt as everyone sat around discussing every possible what-if and never made a single decision. (https://groups.tapatalk-cdn.com/smilies/1733/1534579953.0988-smiley.gif)

I guess that is the most important function of the marketing department, they give us engineers deadlines.  :duh

Spoken like a true ENGINERD! LOL!  :rofl:

I resemble that remark.  :rofl:

Cheers

Steve
Title: Re: Do We Need Linestages ????
Post by: mfsoa on February 15, 2019, 04:37:26 PM
I just got to the point where it just didn't make sense to go with a conventional preamp anymore. Sold my VAC and my CAT. I use my phono rarely and have many digital sources competing for air time. To keep using an analog preamp would have meant denying my reality - I need to switch between digital sources, not analog.

It just made too much sense to go with a Brooklyn DAC+straight to Tommy's latest Megaschino, for what I am up to lately.  Super simple. And flashy VU meters!! :rofl: Can I hear room for improvement? Sure... Who's buying? :thumb:

Clean, very quiet and I'm not chasing that last nth % anymore. I get a bigger thrill from achieving a lot with a little than I do with getting even more but with lots more money! Hence the Raspberry Pis and Allo stuff.

Now I have a large pile of expensive analog interconnects I just don't need.

Would it sound better going into a nice pre? Quite possibly. Do I want to spend the $$. No, not now.

-Mike



Title: Re: Do We Need Linestages ????
Post by: HAL on February 15, 2019, 05:29:38 PM
The setup here is PC via USB to DSP crossover to amps and speakers.

Any analog sources like phono preamp, tuner, etc. go to the 32bit/192KHz minimum phase balanced input ADC. 

The 4 DAC's all have 32bit, 0.5dB/step level adjustment tied to remote volume control.
Title: Re: Do We Need Linestages ????
Post by: mresseguie on February 17, 2019, 04:11:07 AM
Both of my tube preamps make my music sound more pleasant. I prefer to have a preamp over having a DAC/pre combo.
Title: Re: Do We Need Linestages ????
Post by: rollo on February 18, 2019, 11:12:46 AM
Both of my tube preamps make my music sound more pleasant. I prefer to have a preamp over having a DAC/pre combo.


   Spot on !

charles
Title: Re: Do We Need Linestages ????
Post by: pursuitofnow on March 14, 2019, 08:31:08 PM
The amps I use require 2 volts and sound even better with 4-8volts. Everything from dynamics, density, and imaging are just better. So I would think it really depends on your amp to determine if linestages are "needed".
Title: Re: Do We Need Linestages ????
Post by: P.I. on March 14, 2019, 09:58:59 PM
It has been my experience that both voltage output of > 3v is essential along with adequate drive current.

Some years ago I listened to my passive driven by a Cary 306 and also a preamp with a lot of current at the same voltage.  The pre was decisively betterin terms of PRAT.

A big part of what makes it all work are output and input impedance IME.
Title: Re: Do We Need Linestages ????
Post by: rollo on May 15, 2019, 08:28:58 AM
  Agree Dave it is essential to have >3V from source and low input sensitivity of less than 1V for ultimate passive pre performance.
Doug a great preamp, a classic when working.  :-P


charles
Title: Re: Do We Need Linestages ????
Post by: steve on May 16, 2019, 03:23:29 PM
I am a little confused. Do you gents mean greater than 3 or 4 volts output capability, when using a passive control, or another condition? 

Probably a stupid question, but I ask because usually that kind of actual signal voltage output will have the cones parachuting to the floor.   :rofl:

Cheers

steve
Title: Re: Do We Need Linestages ????
Post by: steve on June 02, 2019, 08:57:29 AM
  Agree Dave it is essential to have >3V from source and low input sensitivity of less than 1V for ultimate passive pre performance.

charles

I missed your post Charles, which answers my question, and I agree.

cheers
steve
Title: Re: Do We Need Linestages ????
Post by: rollo on June 11, 2019, 07:40:25 AM
   ARGHAH !! DAC with 3V or more is what the Doctor ordered when using a passive Pre.

charles
Title: Re: Do We Need Linestages ????
Post by: steve on June 12, 2019, 07:41:50 PM
   ARGHAH !! DAC with 3V or more is what the Doctor ordered when using a passive Pre.

charles

Yes, we already agreed with you. Upset?

cheers
steve
Title: Re: Do We Need Linestages ????
Post by: Response Audio on June 12, 2019, 08:53:31 PM
Not a fan of using a source straight into an amp. Even with a passive pre, you dont get the dynamics and impact you would with a preamp. Looses emotion in my opinion.
Title: Re: Do We Need Linestages ????
Post by: rollo on June 20, 2019, 08:55:56 AM
Not a fan of using a source straight into an amp. Even with a passive pre, you dont get the dynamics and impact you would with a preamp. Looses emotion in my opinion.

   Great point which I agree with. After fooling with several passive designs the active preamp is KING for me. When all the bases are covered with a passive one may get more clarity however looses the soul and emotional impact.


charles
Title: Re: Do We Need Linestages ????
Post by: P.I. on June 20, 2019, 08:53:58 PM
Not a fan of using a source straight into an amp. Even with a passive pre, you dont get the dynamics and impact you would with a preamp. Looses emotion in my opinion.

   Great point which I agree with. After fooling with several passive designs the active preamp is KING for me. When all the bases are covered with a passive one may get more clarity however looses the soul and emotional impact.


charles
+1... unless the source has enough voltage and current to adequately drive the amp input at a friendly output impedance through the passive.
Title: Re: Do We Need Linestages ????
Post by: steve on June 23, 2019, 07:13:33 PM
I agree, and of course use a line stage preamp. As we all know, external passive controls that use an interconnect cable have that evil capacitance.

I did a little calculating, and with 4 volts rms musical signal, using a 100k ohm volume control,
the signal current through the pot is only 40 ua (microamps, or millionths of an amp); not much.

With 4 volt rms musical signal, 10k pot, 400 ua, or 0,4 ma (milliamp) through the pot; again not much.
10k is also about as low a resistance load as one can use with capacitive output preamplifiers as bass
response starts or is already dropping.

It is imperative to minimize capacitance in this signal path. With an input volume pot in the pre or the
amp, the capacitance is basically, Miller capacitance, with a smattering of input and stray capacitance.

cheers
steve