First One - mosFET amplifier module

[Lazy Cat]

Running in for now. I am thinking about SMPS dual supply. Hmmm.

Two SMPS1200A400, you won't regret, huge difference.

 

[Lazy Cat]

Strangely, cannot get it running hum free with a shared between the channels linear supply... the strange part is that the VSSA had no probs.

Member Hose4 has mono SMPS and no hum or his whatsoever.

Try to isolate earth connection of your preamp from mains, maybe loop is over earth connections between two chassis?

 

[Lazy Cat]

I could try the SQ difference between 10k pot between DAC (approx. 50 Ohm output impedance) and FO in comparison with DAC directly. But if the outcome of this comparison is likely to be in favour of no pot, I will look for a solution in that direction.

In my DAC I can quite easily adapt volume control before line stage.

2 Pcs. SMPS1200A400 ordered up!

Mark.

Yes, volume controle in front of an output buffer is a correct way.

Two SMPS1200A400

 

[Lazy Cat]

L.C. which speakers are you using for your tests?

Many of them, will prepare the list later. One cannot test on a single pair to get correct impression, also few other persons have to follow the tests, otherwise no success. It is my regular practice to evaluate the amp.

 

[scoutOne]

My current setup is only meant to test if 4 modules are best utilised as a two channel balanced/bridged amp or a 4 channel bi-amp. Once this gets answered it will probably end up as a dual mono. Still, baffled and perplexed about the ground loop sensitivity.

Very interested by your conclusion about balanced / bi-amp question

 

[Mark Verhoeven]

Yes, volume controle in front of an output buffer is a correct way.

It's a tube stage, so with moving the volume control before the output stage, I will introduce more noise in situation where the output is attenuated. That's the only disadvantage I can think of.

Looking at the gain of your amp, I will not need massive attenuation for "normal" listening levels, as my DAC max. output voltage is quite low.

P.S. Received the FO modules this morning!

Mark.

 

[Lazy Cat]

L.C. which speakers are you using for your tests?

Some of them you can see here, two PD.2450 subhorns sub my living room. Avangarde Acoustic Trio + Sub Horn, Focal Scala.

Others for testing purposes are on pics: Zu Audio Soul Supreme, Thiel CS2.4, Gallus Audio Staccato.

 

[danny_66]

Nice collection !

Should be sufficient to evaluate the capabilities of an amplifier
Maybe add another hard coned

 

[BYRTT]

LC that's a serious earth quake simulator under floor your living room thanks showing link. May i ask whats F3

 

[irribeo]

I guess that simulated high pass filter could make a difference

 

[Esperado]

Avangarde Acoustic Trio + Sub Horn,

Multi amped or passive filter ?
Why this strange position of them in the room in your photos , facing each other ?

 

[Mark Verhoeven]

Why this strange position of them in the room in your photos , facing each other ?

Probably while he is using either the La Scala or the Avantgarde. Avantgarde not used to listen at that moment?

 

[Lazy Cat]

It's a tube stage, so with moving the volume control before the output stage, I will introduce more noise in situation where the output is attenuated. That's the only disadvantage I can think of.

Looking at the gain of your amp, I will not need massive attenuation for "normal" listening levels, as my DAC max. output voltage is quite low.

P.S. Received the FO modules this morning!

Mark.

Well if it's tube stage, noise floor level will be set by its performance, hopefully it is not higher than -80 dB.

Usually preamps have volume control in the middle of topology ensuring low Zout by output buffer.

 

[Lazy Cat]

LC that's a serious earth quake simulator under floor your living room thanks showing link. May i ask whats F3

F3

 

[Lazy Cat]

Multi amped or passive filter ?
Why this strange position of them in the room in your photos , facing each other ?

I could not remove them out of the room when Scalas plays.

Trios passive, Sub horns active.

 

[BYRTT]

F3

Bass system achievable -3 dB LF roll off, guess it's not 35Hz. Envious all the man toys you have.

 

[Mark Verhoeven]

Well if it's tube stage, noise floor level will be set by its performance, hopefully it is not higher than -80 dB.

Usually preamps have volume control in the middle of topology ensuring low Zout by output buffer.

Didn't measure, but noise is very low.

 

[back]

wow and i thought i am the only one.

 

[Lazy Cat]

wow and i thought i am the only one.

I know what bass is.

 

[BYRTT]

You serious guys , LC have subs under floor filling several square meters, back has monster driver line placed in wall, guess seen somewhere Esperado run 18", i go home now .