OLDER DECWARE GEAR SUPPORT >> TORII MK III >> Input attenuator setting with CSP3

Message started by qaztar on 03/04/21 at 14:37:12

Title: Input attenuator setting with CSP3
Post by qaztar on 03/04/21 at 14:37:12

Could anybody offer some advice about what to set the common input 'gain' pot to when using a CSP3 as an input? If I max it out with no amp input there is considerable hum. If I set it to where I normally would have it without a CSP3 leading, and then put the CSP3 in line, I notice considerable distortion at high volumes (whereas without the CSP3 I can take it very loud with no distortion). I can't recall if the Torii mk3 was ever offered with fixed gain, but if it was.. what would it be set to?

Title: Re: Input attenuator setting with CSP3
Post by Lon on 03/04/21 at 14:48:14

I've always found this description of the setup in the manual a helpful one:

Operation and Setup
To operate your CSP3, install the tubes, hook up the output jacks to the amplifier. Once you are sure the amplifier and preamp are securely connected together with a high quality interconnect cable between 1 and 5 meters in length you may plug both units into the wall outlet.
Before you turn either piece on make sure that all of the controls on the CSP3 are turned all the way down.
Turn on the CSP3 and let it warm up for one minute. Double check that all the controls are down all the way, including the volume and that the interconnect cables are securely installed into the output jacks of the CSP3 and the input jacks of your amplifier.
Turn on the amplifier. The amplifier should come on and if has a gain control on it, turn it up to the half way point. Your system is now on and at idle. Any noise or hum that you hear is your system reference. Make a note of it so that later when we connect our sources we can see if they added any noise or hum.
It is now time to connect your first source component to one of the input pairs on the CSP3. You can do this while the CSP3 and your amplifier are on and at idle, but be sure you havenít turned any of the controls on the CSP3 up yet.
If you didnít hear any hum or noise increase when you connected your first source that means that A) your cables are probably good and B) there is no ground loop between the components.
No add your second source if you have one and again listen for any increase in noise or hum. If with either source you DO notice an increase in noise or hum then it comes from cables or small ground loops between the components or both. The key here: is the noise or hum acceptable? For example if you have to put your face up to the loudspeaker to hear it, itís acceptable. If however you can hear it from the listening chair it is not acceptable and should be corrected before going any further.
Once everything is connected and warmed up and you are happy that there are no excessive amounts of noise or hum, you can set the controls on the CSP3 to match your amplifierís requirements:
1) turn up the input level controls all the way (clockwise). These are only adjusted during headphone use and only with headphones that get too loud.
2) turn on your source and get some music playing.
3) turn up the main volume control on the CSP3 to halfway.
4) slowly turn the output level controls up until you hear
music playing at a normal listening volume.
5) your preamp is now adjusted properly for your amplifier.
6) further experimentation can be made by adjusting the gain control on the amplifier if it has one relative to the output level settings on the CSP3.

Title: Re: Input attenuator setting with CSP3
Post by qaztar on 03/04/21 at 15:16:49

Thanks. I missed the instruction to initially set the mk3 volume to half way. I see you have a Zrock2 in your system .. do you have it installed before or after your CSP3? Mine is after.

Title: Re: Input attenuator setting with CSP3
Post by Lon on 03/04/21 at 17:32:29

I have used it both ways. Currently I have it before the CSP3 so that headphone listening benefits.

Title: Re: Input attenuator setting with CSP3
Post by Archie on 03/04/21 at 17:50:46

Steve posted an important chart a couple years ago showing CSP3 output voltage for various pot positions. †I use this to maximize my input into my amp while keeping some room to maneuver with the amp pot. †I have found that the maximum input that I can reasonably use into my amp gives me the best sound. †My main source is about 1 volt so I go by that table. †My typical CSP3 settings are Output pots = 10, Input pots = 8, Master pot = 10 and my amp pot between zero and 10 o'clock.

One thing. †I continually get confused by what is called "input" and "output" on the CSP3. †The two pots close to the front I set to 10 and leave whereas the two puts further back are the ones I adjust for output voltage. †The chart is also helpful when using a ZROCK2 after the CSP3 to track the voltage into the ZROCK2 so as to not overload it.


Note: †Outputs set to full, Volume set to full. †Input pots set to zero and charted through their range.


Position = †Volts
0 = 0V
1 = 156mV
2 = 492mV
3 = 1.53V
4 = 2.8V
5 = 4.0V
6 = 5.1V
7 = 12.22V
8 = 25.0 V
9 = 32.0 V
10 = 32.0V


Position = Volts
0 = 0V
1 = 60mV
2 = 200mV
3 = 552mV
4 = 1.05V
5 = 1.5V
6 = 1.9V
7 = 4.8V
8 = 7.7V
9 = 10.12V
10 = 10.12V

The max input voltage with the input control set all the way up is 3.38V. †At that point slight clipping is seen at the full 35V output. †If you trim the master volume down and the output control down, the distortion will become inaudible but it will still be there, just at 15 times lower level. †That means you can shove 10 volts into it but it will always sound better set to 3.38 or less.

Keep in mind these figures are with the CSP3 connected to my test gear which is 178KOhms so the output voltage will vary somewhat into different loads. †Also keep in mind the 120V at the outlet and the tubes you use will effect these results making them go up or down.


Title: Re: Input attenuator setting with CSP3
Post by Lon on 03/04/21 at 17:52:56

The two pots closest to the front are the Input pots.

Title: Re: Input attenuator setting with CSP3
Post by Archie on 03/04/21 at 18:39:47

So, I'm doing it backwards? †If so, it's a misunderstanding that I've had from the beginning. †I seem to remember the front pots were for regulating volume when using headphones.

I'll switch it up tonight and hopefully my sound will improve. †If it's as good as it is doing it backwards, maybe I'll get a real gift! † [smiley=50.gif]

Title: Re: Input attenuator setting with CSP3
Post by Lon on 03/04/21 at 18:49:08

Odds are you might have the best sound this way. According to the manual Steve does indicate that the input pots are for headphones and says leave them be if notusing those. (I never leave anything be though, in my other system and wtih a CSP2+ with the mods I have them on 7 or 8). In my CSP3 with the 25th Anniversary mods Steve bypassed the input pots and gave me a glass resistor. So I can only adjust the output pots. Using a ZTPRE, ZBIT and ZROCK2 before the CSP3 my output pots are generally low, 4 or 5.

Title: Re: Input attenuator setting with CSP3
Post by Archie on 03/04/21 at 19:43:02

Okay, maybe then I'm not completely hallucinating. †If your Input (front) are bypassed, that seems like me having mine on 10.

Title: Re: Input attenuator setting with CSP3
Post by JD on 03/04/21 at 22:25:52

I haven't used my Torii III in a few months but when I used it with the CSP2+ preamp I'm pretty sure I never had the Torii volume pot above half way unless it was party mode and clarity wasn't a concern.


Title: Re: Input attenuator setting with CSP3
Post by will on 03/05/21 at 01:49:19

My room is pretty big, but perhaps I have a different view being a gain rider for optimal sound, never using a pre specifically as volume. And I find I can get into distortion in many ways, by pushing any of my gains too hard in concert with the others being borderline.

I use the CSP3 in front of the Torii entirely for the best sound I can get from the CSP3-Torii interaction. Also, in my system/room, my Torii (and CSP3 to some extent) are toned back with milder tubes, so not full power. And with the HR-1s in this space, I can get close to distortion edges near my preferred serious listening levels no matter how I adjust the gains.... The way I have the pots on the CSP3 set, the Torii, CSP3, and ZBIT master gains all end up near or past 3 o'clock, and the Torii usually within a few notches of the top when doing serious listening.

Just to say, all this depends on a lot of things, and starting with known settings, and then experimenting was the best way to find your best gain balances and sound for me.

In case gain riding interests you, I am copying part of a post I made in another thread:

"I am a huge fan of two gain stages personally. In fact I typically use what are in effect three gains....a ZBIT (adjustable balanced out from DAC, wide open is the DAC voltage out, so gain adjustment is attenuation, but quite useful for balancing gains), a CSP3, and a Torii. I have never used my Zstage or CSP3 for a volume control, instead using them as gain balancing adjustments for "gain riding." In my case, the Torii IV sounds more-or-less neutral at different volumes, so to me it is the best "volume control." Whereas, the pre stages I use, especially the CSP3, there is a quite meaningful amount of tonal/density variation depending on the voltage out of the CSP3, and how that effects the amp sound. This can be a great tool if baseline gains are set between them to be about neutral, and then adjust the CSP3 to tune/optimize the signal intensity as a means of improving on the many different recording styles we hear.

Keeping an optimal listening volume while riding the gains between the CSP3 and Torii, more CSP3/less Torii, gives a more intense signal...more density, weight, dynamics, more bass and more lucidity....better for leaner recordings. And less CSP3/more amp gain, the signal goes lighter, leaner, less intensity of weight, bass, dynamics, lucidity.....better for thicker recordings. I have mine tuned so that I can go too lean and too intense, giving a wide range in the middle for gain tuning on the fly, often making a few little adjustments for most albums at this point."

Hope this helps some.


Title: Re: Input attenuator setting with CSP3
Post by Archie on 03/05/21 at 06:53:13

Playing with the Inputs vs the Outputs I honestly don't hear a difference. †For all I know, they are wired the same.

Title: Re: Input attenuator setting with CSP3
Post by will on 03/05/21 at 07:13:46

That has not been my experience, but I wonder.... I always use different tubes in the input versus the outputs. So though the input and outputs do different things in creating the sound, the input feeding the outputs does connect them, but they are different.... it makes me wonder if you are using the same tubes in both positions, making differences less notable?

Title: Re: Input attenuator setting with CSP3
Post by Archie on 03/05/21 at 17:02:27

I currently have 6N1P-EVs in all three positions. †I used to run a Tungsram PCC88 in the front slot but I had 2 go bad prematurely †(never when used in my ZMA though).

I need to play around more. †Last night I was only playing some Mozart symphonies and they may not have been the best music to notice changes.

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