Topic: Bypassing a R-09 internal preamp. Is it possible?

[guysonic]

Using LINE input jack and setting deck gain to 8-13 seems like a 'unity' mode where neither + or - gain is being applied inside the deck's CODEC IC. 

This is your only tact to take for having no internal deck gain as far as I can see. 

[evilchris]

the CA pre is quieter than the r-09 pre, for sure.

Using LINE input jack and setting deck gain to 8-13 seems like a 'unity' mode where neither + or - gain is being applied inside the deck's CODEC IC. 

I'll split the diff and run @ 11 for the next show.  Thanks for the tip.

Now if I can figure out why my CA pre is so noisy when I turn the knob.

[Dede2002]

Using LINE input jack and setting deck gain to 8-13 seems like a 'unity' mode where neither + or - gain is being applied inside the deck's CODEC IC. 

This is your only tact to take for having no internal deck gain as far as I can see. 

Thanks Guysonic. Solid information, as usual

[Dede2002]

the CA pre is quieter than the r-09 pre, for sure.

Using LINE input jack and setting deck gain to 8-13 seems like a 'unity' mode where neither + or - gain is being applied inside the deck's CODEC IC. 

I'll split the diff and run @ 11 for the next show.  Thanks for the tip.

Now if I can figure out why my CA pre is so noisy when I turn the knob.

Noisy? 
You mean if turn the knob all the way up, right?

[evilchris]

Now if I can figure out why my CA pre is so noisy when I turn the knob.

Noisy? 
You mean if turn the knob all the way up, right?

No ... If I turn the knob, it create static while I'm turning it.  Almost as if there's something wrong with the knob itself.

I gotta talk to Chris about it.  I'm not sure what's going on with it.

[Dede2002]

Now if I can figure out why my CA pre is so noisy when I turn the knob.

Noisy? 
You mean if turn the knob all the way up, right?

No ... If I turn the knob, it create static while I'm turning it.  Almost as if there's something wrong with the knob itself.

I gotta talk to Chris about it.  I'm not sure what's going on with it.

Ah, understood. I'm sure Chris will take care of this issue. He's super fast and is always there for his customers. That's what I'm told...

[fransb]

I also experience this noise when turning the knob on my ST-9100 (as input to my H120) Chris told me he can't address this issue... 
By the way the noise is absent when switching the high pass filter to ON.

[evilchris]

By the way the noise is absent when switching the high pass filter to ON.

I'll test this tonight.  +t for the tip.

[guysonic]

I also experience this noise when turning the knob on my ST-9100 (as input to my H120) Chris told me he can't address this issue... 
By the way the noise is absent when switching the high pass filter to ON.

A potentiometer with DC voltage riding along with the audio can sound very noisy when adjusted. 

The high pass filter usually uses a capacitor blocking all DC voltages making knob adjustments noiseless.  This situation usually can be remedied with a circuit design change that reduces the DC component in the audio signal with/without the Hi Pass filter being on.

[Church-Audio]

AFAIK, the "preamp" is always there, whether mic in or line in.
Just the gain changes.  I don't know where the official "zero gain" is, but running line in at a moderate level,
say #15/30, might be a good guess.

Unlike Minidisc, for example, there is only one gain stage, marked "PGA" (programmabable gain) on the block diagram (*).  Minidisc has a separate mic gain stage, so basically two PGA stages, one for mic and a second for line.  So, putting line in on the MD you *do* avoid an extra gain stage, but not so on the Edirol.

(*) The chip is Burr Brown, "tlv320aic32", if you want to look at the specs in detail.  This is a single chip that does everything, mic/line in, ADC, MP3 compression (if applicable), headphone amp, etc.  The good news is there are no external parts for Edirol to mess up.  The bad news is no "mods" for me to do, lol.

  Richard

Great info. Appreciate it. 
I'd heard lots of things about the R-09 unity gain setting. I've seen 8, 13 and even 18. I really don't know what to think.
But I'd love to know.

I will do a test tomarrow and let you know what it is.

Chris

[evilchris]

By the way the noise is absent when switching the high pass filter to ON.

I'll test this tonight.  +t for the tip.

confirmed.  flipping the HPF on did the trick.  too bad i don't ever NEED the HPF. 

if my R-09 didn't make volume changes so obvious (you can almost hear the "click click click" from pushing the input adjustments), i probably wouldn't mind.  as it is, though, this is sort of irritating.

must ... find ... solution.

[Church-Audio]

By the way the noise is absent when switching the high pass filter to ON.

I'll test this tonight.  +t for the tip.

confirmed.  flipping the HPF on did the trick.  too bad i don't ever NEED the HPF. 

if my R-09 didn't make volume changes so obvious (you can almost hear the "click click click" from pushing the input adjustments), i probably wouldn't mind.  as it is, though, this is sort of irritating.

must ... find ... solution.

Its just part of the design. I have tryed to fix it and short of adding another gain stage.. I cant.. So what I suggest is think of my preamp as a gain block set the level on the preamp to 75 to 100% and leave it. Then when you need to make fine adjustments use your recorder. Really this preamp should have had a stepped gain control with resistors instead of a continuously variable knob.  But the pot was much cheaper and allowed me to keep the size/cost down..

I wanted to just make it fixed but, I figured it would be nice to be able to set it from unity gain or 11'oclock to +20 db full. Its very hard to make a preamp this size and get the same exact parts all the time. I had to not only design the preamp so that it would work and be very high performance. I also had to design it so that I could always get the exact same parts and build them exactly the same way. All 3.0 preamps are the same right down to the last resistor.  All v3.2 preamps are exactly the same. When your a very small company like me, you have to build things based on the availability of a continuous supply of the same parts... Is the 9100 perfect NO, but its not $500 its $179 and I think at that price point its a pretty good product. I have always worked hard to do updates to the circuit but this is one thing I just cant fix with out spending a lot of money and changing the size of the box. Two things that most of my customers dont want.


Chris

[evilchris]

Is the 9100 perfect NO, but its not $500 its $179 and I think at that price point its a pretty good product.

Agreed.  Sorry if you felt like I was being overly critical.

I have always worked hard to do updates to the circuit but this is one thing I just cant fix with out spending a lot of money and changing the size of the box. Two things that most of my customers dont want.

+T for the honesty.  Is this a problem across all of your pre-amps?  Something to be addressed in the transformer-based pre?

[Church-Audio]

Is the 9100 perfect NO, but its not $500 its $179 and I think at that price point its a pretty good product.

Agreed.  Sorry if you felt like I was being overly critical.

I have always worked hard to do updates to the circuit but this is one thing I just cant fix with out spending a lot of money and changing the size of the box. Two things that most of my customers dont want.

+T for the honesty.  Is this a problem across all of your pre-amps?  Something to be addressed in the transformer-based pre?

I totaly dont feel like your being over critical at all. You had questions and I have answers. Everything I sell has been looked at by me 1000 different ways.. Objectively there is not much I can do to fix this would out increasing the price and size of the product. But I cant expect everyone to understand unless you design and build things and sell 1000's of preamps all built by hand one at a time.

Its hard for me to do this business because I cant buy 1000 potentiometers at a time.. I cant wait 2 months for a company to make them for me. So I am limited by what is available and I rely heavily on my suppliers to stock parts so that when the demand is there for my product, I can pick up the phone and with in 5 days have enough parts to build what ever is needed.

I am just at the level where I really should have someone else working for me. But where I live there is no people that I could hire that would have the skills.. So I stay low profile I dont advertise as much as I could. Right now I build about 30-40 preamps a month.. That's a lot for one person I also sell about 25 pairs of mics a month. All built by me. I cant really build to much more then that by hand.

So I have to stay the size I am until its time to do my next major move.. Mass production of certain things. Luckily I have great customers like you * not trying to kiss your ass * people that are willing to wait for my product and I am very grateful for your business and your comments. They push me to do better. I remember when people wanted a clip light on my preamp.. I resisted and said I really could not do that. Well its done.. Its there a clip light does not sound like a big deal, but to me it was because all of the parts of that circuit had to fit inside my existing preamp enclosure and my existing circuit board and they had to have ZERO effect on the performance of my preamp. I will work on this problem.. I will try to find a solution because of people like you my products are better.



This problem is only with the st-9100 preamp and not with the ugly or the 9000 preamp.
The transformer based preamp will not have any issues because its a no compromise product.

Chris

[Dede2002]

Is the 9100 perfect NO, but its not $500 its $179 and I think at that price point its a pretty good product.

Agreed.  Sorry if you felt like I was being overly critical.

I have always worked hard to do updates to the circuit but this is one thing I just cant fix with out spending a lot of money and changing the size of the box. Two things that most of my customers dont want.

+T for the honesty.  Is this a problem across all of your pre-amps?  Something to be addressed in the transformer-based pre?

I totaly dont feel like your being over critical at all. You had questions and I have answers. Everything I sell has been looked at by me 1000 different ways.. Objectively there is not much I can do to fix this would out increasing the price and size of the product. But I cant expect everyone to understand unless you design and build things and sell 1000's of preamps all built by hand one at a time.

Its hard for me to do this business because I cant buy 1000 potentiometers at a time.. I cant wait 2 months for a company to make them for me. So I am limited by what is available and I rely heavily on my suppliers to stock parts so that when the demand is there for my product, I can pick up the phone and with in 5 days have enough parts to build what ever is needed.

I am just at the level where I really should have someone else working for me. But where I live there is no people that I could hire that would have the skills.. So I stay low profile I dont advertise as much as I could. Right now I build about 30-40 preamps a month.. That's a lot for one person I also sell about 25 pairs of mics a month. All built by me. I cant really build to much more then that by hand.

So I have to stay the size I am until its time to do my next major move.. Mass production of certain things. Luckily I have great customers like you * not trying to kiss your ass * people that are willing to wait for my product and I am very grateful for your business and your comments. They push me to do better. I remember when people wanted a clip light on my preamp.. I resisted and said I really could not do that. Well its done.. Its there a clip light does not sound like a big deal, but to me it was because all of the parts of that circuit had to fit inside my existing preamp enclosure and my existing circuit board and they had to have ZERO effect on the performance of my preamp. I will work on this problem.. I will try to find a solution because of people like you my products are better.



This problem is only with the st-9100 preamp and not with the ugly or the 9000 preamp.
The transformer based preamp will not have any issues because its a no compromise product.

Chris

+T for honesty. That's why I keep bugging you all the time 
I'm really impressed. Your costumers ( and I'll be one of them, that for sure) are always by your side. This is what counts.
Take care, keep up the great work and, please, let me know about my request . I must have the 9100.