Slewmaster - CFA vs. VFA "Rumble"

[thimios]

and make again loopback measurement, compare this with "clear" loopback. Results should remain unchanged, it should be the same picture as above. According your pictures, connecting input cable shield (so creating ground loop) worsen results more than one order of magnitude, for the same amp.

Do you mean something like this?

 

[BV]

Yes, amp should be on. How looks the same measurement with disconected conection to amp ground (output GND)?

 

[thimios]

Yes, amp should be on. How looks the same measurement with disconected conection to amp ground (output GND)?

I can repeat this soon .
This photo is from a previous amplifier measurement.
You want a loop test with and without connection to a power on amplifier gnd if i understand well.

 

[BV]

Yes, amp conected to mains and switched on.

 

[still4given]

Hi Thimios,

Which version of BV's mod did you do? I am trying to get the one attached to work and it won't. Today I built another board to see if maybe I had done something wrong with the first one and still it won't play nice. Would you or anyone have a look at the board and see if it looks like it follows the schematic properly. It may be that I just modified it wrong but I have been over it several times and I just can't find the problem. It sims fine but won't work right for me.

Thanks, Terry

 

[famousmockingbird]

I just got my PCB's today from Jason and plan on building a two channel stereo. I got two boards each:

Slewmonster 5P EF3 OPS

CFA-XH IPS

Are you guys running them off of standard dual-polarity (split) supplies?

Can somebody please recommend me a good "bang for your buck" transformer. It will be driving some Klipsch Heresy's so I don't need a lot of output power, they are 100 watt max, 94db, 8 ohm speakers.

Thanks

 

[gannaji]

2 thimios

Are somewhere asc file (and included models) available?

Post 800 ?

 

[still4given]

I just got my PCB's today from Jason and plan on building a two channel stereo. I got two boards each:

Slewmonster 5P EF3 OPS

CFA-XH IPS

Are you guys running them off of standard dual-polarity (split) supplies?

Can somebody please recommend me a good "bang for your buck" transformer. It will be driving some Klipsch Heresy's so I don't need a lot of output power, they are 100 watt max, 94db, 8 ohm speakers.

Thanks

I have one of these.
400VA Antek Power Transformers An 4234 | eBay
Pretty good bang for the buck. Will give you +-50V rails. The amp will run fine on that.

 

[famousmockingbird]

I have one of these.
400VA Antek Power Transformers An 4234 | eBay
Pretty good bang for the buck. Will give you +-50V rails. The amp will run fine on that.

Sounds like it is just what I need. I found another thread on here about Antek and it seems people had good experiences with them.

Thank you

 

[thimios]

Hi Thimios,

Which version of BV's mod did you do? I am trying to get the one attached to work and it won't. Today I built another board to see if maybe I had done something wrong with the first one and still it won't play nice. Would you or anyone have a look at the board and see if it looks like it follows the schematic properly. It may be that I just modified it wrong but I have been over it several times and I just can't find the problem. It sims fine but won't work right for me.

Thanks, Terry

Hi Terry
My last modification is according to pdf on post 2974.

 

[BV]

Thimios, I suppose (I hope..) you are using 24bit regime in measurments. And use ASIO.

 

[thimios]

Thimios, I suppose (I hope..) you are using 24bit regime in measurments. And use ASIO.

I will examine this soon ,i will try to find these adjustments in ARTA software.
Yes ,24bit
ASIO?
PS.This loop test ASIO used.

 

[still4given]

Hi Terry
My last modification is according to pdf on post 2974.

Weird, that is the same one I can't get to work. If you can find the time, would you please look over the modified board layout I posted and see if you find any errors?

Thanks, Terry

 

[Kindhornman]

Thimios,

What is ASIO (Audio Stream Input/Output)?

 

[thimios]

New configuration, asio driver

Asio driver based measurements.
The same with RMAA.
Amplifier is CFA simple.

 

[Bigun]

Amplifier is CFA simple.

Looks nice to me. Do we need more than a simple CFA....

 

[thimios]

Looks nice to me. Do we need more than a simple CFA....

Hi Bigun thanks for reply.
If this config. is ok i will try all my amplifiers.
I see your tests,what software you used?

 

[5th element]

How is that nice? The CFA should be more like 0.003% at 20kHz, thimios would almost be at 1%!

 

[thimios]

How is that nice? The CFA should be more like 0.003% at 20kHz, thimios would almost be at 1%!

Where are you see 1%?
BTW now we must be sure for test setup only.

 

[BV]

thimios
Try a loop test, as in #3092, but with connected loop shielding to amp GND..

Where you see 1%?

Measure with Fs=192kHz , so you can see distortion artefacts to 90kHz and do swwep 20Hz-20kHz.