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crazy bill the eel killer  
#1 Posted : Saturday, November 20, 2010 6:55:27 AM(UTC)
crazy bill the eel killer

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Hello all,

New here and looking forward to eventually building one of your DAC's and the reason for this post, the Ventus headphone amp ( I need this soon ). TBH, I'm a tube and vinyl guy, but I listen almost exclusively to cans now ( Senn HD650 or AKG 701 ), and the background silence of digital is beguiling through the phones. I actually enjoy well recorded CD's now.

My problem.

I want to build the Ventus, but I notice it's got balanced inputs and all my sources are single ended. Eventually I'll hook it up on the back end of one of your DAC's, but for now I want to feed it w/ my tube preamp, which is actually a buffer ( cathode follower ) with an output impedance of approx 1K. So my question :

1). What is the input impedance of the Ventus. Is it too low for my preamp, or will the combo be OK ?
2). Can the inputs be configured to accept unbalanced inputs w/o using an input transfo to convert to balanced ?
3). I didn't see any reference for power requirements. I noticed the supply needs to be +-, but no values are given. What voltage range would be acceptable, and would one of your supplies work. Eventually I would like to use battery supplies for this.

I thank you in advance for your help.

Cheers, Crazy Bill
Russ White  
#2 Posted : Saturday, November 20, 2010 7:16:36 AM(UTC)
Russ White

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Actually the Ventus can be used for balanced input, or it can be setup as an ordinary non-inverting or inverting amp with SE input.

When setup as a non-inverting amp the input impedance can be very high. 100K (set with a resistor) would be fine.

The supply rails should be 15V.
eitancoh  
#3 Posted : Saturday, November 20, 2010 10:01:29 AM(UTC)
eitancoh

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Hi

if using the ventus with a buffalo (or opus for that matter) with a volumite, will it require a pot to control volume? will such a combo be enough to drive low impedance headphones with the need to amplify the sound?

Thanks

Eitan
Russ White  
#4 Posted : Saturday, November 20, 2010 2:57:06 PM(UTC)
Russ White

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Do you understand the purpose volumite? ;)

The Ventus is designed to drive headphones even 16ohm headphones. :)
crazy bill the eel killer  
#5 Posted : Saturday, November 20, 2010 7:23:29 PM(UTC)
crazy bill the eel killer

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Hello Russ,

Thanks for the quick reply. I've had my three year old grandson all day, so opening the computer is OK only if I want to watch Batman, Spiderman, or Toy Story. Sorry it took so long to get back.

I'm totally new at SS, and fairly new at tubes. So am I correct that when you say the rails should be 15v that you mean +- 15v,and that the Placid BP with the 15v transformer would be appropriate here ?

As soon as you tell me that The Placid BP w/ the 15v transfo is correct, I'll place the order and get going.

I'll then have a bunch more questions, as I'm sure laying out quiet SS circuits is significantly different than laying out quiet tube circuits.

Thanks for all your help.

Cheers, Crazy Bill
Russ White  
#6 Posted : Saturday, November 20, 2010 7:50:25 PM(UTC)
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Hi Bill,

You are correct. Placid BP or LCBPS would both be solid choices for power supply here.

Also a dual 15V secondary to get +/-15VDC out of the bipolar supply is exactly what you want.

Very glad to help. Have fun!

Cheers!
Russ
crazy bill the eel killer  
#7 Posted : Saturday, November 20, 2010 8:58:27 PM(UTC)
crazy bill the eel killer

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Thanks Russ,

Ventus, Placid BP and transfo ordered. I can't tell you how excited I am to get this project underway. I've been using my NAD 3020A to drive my cans since I took my SE EL84 amp apart, and while very good, I have no doubt that your circuits are in a completely different league altogether.

I'm presently using a tube buffer ( Decware ZSLA-1 Sig ) as a preamp. While very good, it can be improved upon. I plan on building a new tube preamp to drive the Ventus, so I need a couple of specs to get started.

If it's possible, could you please provide the following:

1). Maximum input voltage ( rms or pk-pk )
2). Sensitivity for 1mw or full output ( please specify which, again, rms or pk-pk ).

Again, many thanks for all your help,

Cheers, Crazy Bill

crazy bill the eel killer  
#8 Posted : Saturday, November 20, 2010 10:12:27 PM(UTC)
crazy bill the eel killer

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Forgot to add,

BTW, having fun is exactly what I am doing. Thanks for providing a product and service like this to us hopelessly addicted DIYers.

Cheers, Crazy Bill

Russ White  
#9 Posted : Sunday, November 21, 2010 8:11:35 AM(UTC)
Russ White

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crazy bill the eel killer wrote:
Thanks Russ,

Ventus, Placid BP and transfo ordered. I can't tell you how excited I am to get this project underway. I've been using my NAD 3020A to drive my cans since I took my SE EL84 amp apart, and while very good, I have no doubt that your circuits are in a completely different league altogether.

I'm presently using a tube buffer ( Decware ZSLA-1 Sig ) as a preamp. While very good, it can be improved upon. I plan on building a new tube preamp to drive the Ventus, so I need a couple of specs to get started.

If it's possible, could you please provide the following:

1). Maximum input voltage ( rms or pk-pk )
2). Sensitivity for 1mw or full output ( please specify which, again, rms or pk-pk ).

Again, many thanks for all your help,

Cheers, Crazy Bill



1) this will depend on the gain you want. :)
2) See #1 :)

If you are planing on using the Ventus non-inverting then just let me know what gain you would like and I will suggest resistor values for you to get that gain.

Cheers!
Russ

Edited by user Sunday, November 21, 2010 8:12:09 AM(UTC)  | Reason: Not specified

Russ White  
#10 Posted : Sunday, November 21, 2010 8:15:00 AM(UTC)
Russ White

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If you are planning on using a pre-amp in front of the Ventus you would probably want to setup the Ventus for unity gain. This is pretty easy.
NicMac  
#11 Posted : Sunday, November 21, 2010 11:07:16 AM(UTC)
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Talking about the Ventus.....
I'm planning to use it between a dual-mono Buffalo II/Legato combo and modified Hypex UcD modules (replacing the IVY III I'm currently using). My goal is to go fully discrete, eliminate caps in the signal path and to recover some of the gain I lost by modifying the UcD modules.
Q1: Can the Legato and Ventus be DC-coupled (bypassing the output caps on the Legato)?
Q2: Will the output of Ventus be DC-free (the bypassed UcD's are quite sensitive to DC offset)?
Q3: How and within what range can the gain of the Ventus be set? Manual for Ventus?
Q4: Better to increase gain on Legato, Ventus or both (I would like a total gain of 5-6)?
Thanks and keep up the good work!
Nic
szabokristof  
#12 Posted : Monday, November 22, 2010 5:57:22 AM(UTC)
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Hello Russ,

I'm planning to build a complete headphone system. This will be my primary music listening equipment. I have HD800 headphones. I decided to buy two Buffalo dacs for dual mono operation and two Joshua Tree for the balanced volume control. If I order a Ventus amp too, can I connect it directly to the buffalo dacs (to the JT) or should I use I/V stage? Can I use two Ventus per channel for balanced output to HD800? Is this amp class A? Is this amp a high end class device like B22 or is it better?

Thanks,
Kristóf
Russ White  
#13 Posted : Monday, November 22, 2010 7:50:51 AM(UTC)
Russ White

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NicMac wrote:
Talking about the Ventus.....
I'm planning to use it between a dual-mono Buffalo II/Legato combo and modified Hypex UcD modules (replacing the IVY III I'm currently using). My goal is to go fully discrete, eliminate caps in the signal path and to recover some of the gain I lost by modifying the UcD modules.
Q1: Can the Legato and Ventus be DC-coupled (bypassing the output caps on the Legato)?
Q2: Will the output of Ventus be DC-free (the bypassed UcD's are quite sensitive to DC offset)?
Q3: How and within what range can the gain of the Ventus be set? Manual for Ventus?
Q4: Better to increase gain on Legato, Ventus or both (I would like a total gain of 5-6)?
Thanks and keep up the good work!
Nic


1: Yes most likely. But see #2.
2: You should be able to trim out any offset using the pot on the Ventus. But it may drift slighlty with temperature changes (maybe a couple mv)
3: The gain can be just about anything you like, but the output swing will be limited by the load and the rails etc.
4: Set the gain at the Ventus. Legato works best at the stock gain.

Thanks for the kind words.
Russ White  
#14 Posted : Monday, November 22, 2010 7:59:13 AM(UTC)
Russ White

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szabokristof wrote:
Hello Russ,

I'm planning to build a complete headphone system. This will be my primary music listening equipment. I have HD800 headphones. I decided to buy two Buffalo dacs for dual mono operation and two Joshua Tree for the balanced volume control. If I order a Ventus amp too, can I connect it directly to the buffalo dacs (to the JT) or should I use I/V stage? Can I use two Ventus per channel for balanced output to HD800? Is this amp class A? Is this amp a high end class device like B22 or is it better?

Thanks,
Kristóf


You could go directly out the Buffalo II to the JT and then Ventus, but I would not do so. It will not be ideal because you will be using the DAC as a voltage source, and it works much better as a current source.

I would use IVY-III prior to the JT to do the I/V conversion for your app. You can indeed use two Ventus per channel, but I can tell you from personal experience that the IVY-III can actually drive HD600,HD650, and HD800s very well all by itself. It sounds incredible.

I would also probably go with the Volumite over the JT here but that is purely your call. Either will work very well.

All you really *need* for awesome headphone use is BufII, IVY-III, and Volumite + PSs etc. Adding either 2 or 4 ventus would make driving low impedance cans (say < 100Ohms) incredibly awesome. :)

Cheers!
Russ
stephen1212b  
#15 Posted : Monday, November 22, 2010 1:15:42 PM(UTC)
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Stock fed balanced from an IVY what is the overall gain?
Russ White  
#16 Posted : Monday, November 22, 2010 1:50:19 PM(UTC)
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With stock parts it is unity gain. But that is easy to adjust to your liking.
szabokristof  
#17 Posted : Tuesday, November 23, 2010 6:50:41 AM(UTC)
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Russ White wrote:
szabokristof wrote:
Hello Russ,

I'm planning to build a complete headphone system. This will be my primary music listening equipment. I have HD800 headphones. I decided to buy two Buffalo dacs for dual mono operation and two Joshua Tree for the balanced volume control. If I order a Ventus amp too, can I connect it directly to the buffalo dacs (to the JT) or should I use I/V stage? Can I use two Ventus per channel for balanced output to HD800? Is this amp class A? Is this amp a high end class device like B22 or is it better?

Thanks,
Kristóf


You could go directly out the Buffalo II to the JT and then Ventus, but I would not do so. It will not be ideal because you will be using the DAC as a voltage source, and it works much better as a current source.

I would use IVY-III prior to the JT to do the I/V conversion for your app. You can indeed use two Ventus per channel, but I can tell you from personal experience that the IVY-III can actually drive HD600,HD650, and HD800s very well all by itself. It sounds incredible.

I would also probably go with the Volumite over the JT here but that is purely your call. Either will work very well.

All you really *need* for awesome headphone use is BufII, IVY-III, and Volumite + PSs etc. Adding either 2 or 4 ventus would make driving low impedance cans (say < 100Ohms) incredibly awesome. :)

Cheers!
Russ


Hi Russ,

Thank you for your answer. I have just a few questions. :)
Why did you offered Volumite and not the JT for the volume controll? If I use the Volumite to the BuffII do I control the volume in the digital domain, or is the ESS chip has an analog volume controll module? If it is in a digital domain don't you think the resolution will be a problem in a low volume level?
Can I do (modify) something in the IVY-III to make it more better (best headphone amp)?
And finaly :) you wrote that the Buff+IVY+Volumite will be awesome, and adding a Ventus for low impedance cans will be incredibly awesome. If I add ventus for the HD800 (high imp.) will be any difference like between awesome and incredibly awesome? :) (Oh, one more thing. Is the Ventus class A in the LME49600?)

Thans a lot!
Kristóf
crazy bill the eel killer  
#18 Posted : Monday, November 29, 2010 4:28:25 PM(UTC)
crazy bill the eel killer

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Hello Russ,

Pkg arrived Friday, and I must say I'm impressed by the quality offered in this kit.

First newbie question.
I have no SS experience other than a cascode FET CCS in my tube circuits ( haven't actually built it yet though ), and of course they are static sensitive. Are any of the active devices in your kit static sensitive, or can I handle them w/o fear of damage.

Also, I've read all I can find on the net about the Ventus, and I should be able to figure out how to set the gain at whatever I need. I'll assess my gain structure and figure out where I need to be, do the calcs, and then ask here before I actually solder. I have great flexibility in the gain of the tube preamp, so I have the option of having the preamp provide all of the gain, having the Ventus provide all of the gain, or anywhere in between. So the question this prompts is :

In your experience ( or anyone else feel free to chime in ), have you noticed any difference in how the circuit sounds between being configured purely as a buffer or using gain. There are significant sonic differences in how I configure the tube preamp, so I have some flexibility to fine tune between the two.

I thank you in advance for your help.

Cheers, Crazy Bill
Brian Donegan  
#19 Posted : Monday, November 29, 2010 5:01:01 PM(UTC)
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Quote:
Are any of the active devices in your kit static sensitive, or can I handle them w/o fear of damage.


Nothing in the kit is overly static sensitive. Nothing to worry about.
crazy bill the eel killer  
#20 Posted : Monday, November 29, 2010 6:38:20 PM(UTC)
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Thanks Brian

Appreciate the quick answer. That will help, of course, as I haven't a clue how to handle sensitive devices anyway.d'oh!

One less thing to Google.

Cheers, Crazy Bill
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