Simple Killer Amp - Listening impressions

[lineup]

Originally posted by ShinOBIWAN
Eh? What the....
Are you calling Greg a queen because I absolutely see no relevance to your post.

Everybody can not see everything. At least not at once .....
You can smoke whatever you want, ShinOBIWAN

[tja]

Originally posted by ShinOBIWAN


It says 'account disabled' near his avatar. Find one of his post's and you'll see. If he was active it would 'DIYAudio Member' and if he was sinbinned it would likewise say just that.

Perhaps a mod could clear up exactly what has happened to Greg.

If he was banned it would say 'banned', not 'account disabled'. Maybe he has disabled it himself?

Take

[SY]

Queen? Oh, lord.

"Speculation in the absence of data is a capital mistake," or so said my childhood hero, Sherlock Holmes.

As members, we have the obligation to follow the rules of the community, or we don't participate. Everyone has that choice- moderators and admins are no exception. Nor does being in the industry give one a free pass. Other industry participants seem to do fine under our strictures.

Now, what was the actual subject of this thread again?

[ShinOBIWAN]

Originally posted by lineup


Everybody can not see everything. At least not at once .....
You can smoke whatever you want, ShinOBIWAN

Ouch it must have hurt.

[ShinOBIWAN]

Originally posted by SY

Now, what was the actual subject of this thread again?

Talking about the finer points of Greg's design in his absence?

[anatech]

Hi ShinOBIWAN,
It's just like any other amp discussion. The creators are not always here but it's still worthy of a talk.

I think it's good you can share your opinions and experiences about the equipment.

-Chris

[ShinOBIWAN]

Originally posted by anatech
Hi ShinOBIWAN,
It's just like any other amp discussion. The creators are not always here but it's still worthy of a talk.

I think it's good you can share your opinions and experiences about the equipment.

-Chris

I know Chris.

Its a true land of freedom that we live in.

[KLe]

Hi Greg
Its an excellent VASless design (unless, its hiding?), and, I have placed my order for a pair of your GB300D (300W Class AB MOSFET) amplifier module kits
Is a 300VA transformer, and +/-70V supply rails, per channel sufficient/ok I know of a nice +/-60V SMPS. Perhaps, I could change the PS to it at a later date.

thanks again
KL

[Miles Prower]

"Its an excellent VASless design (unless, its hiding?)"

Not really VAS-less since that function is incorporated into the first stage LTP by bootstrapping it for higher than usual gain. I've seen similar designs that accomplish the same thing by using active loads with the first stage LTP.

[AndrewT]

Hi Kle,
if you want to copy how the CHEAP manufacturers assemble their amps then go ahead and put in too small a transformer.
However if you want a reasonably balanced assembly then I recommend that you use a transformer with a VA rating =1.5 times the maximum output power i.e. 450VA.
GB300 is very efficient in terms of output power vs Vrail potential according to the designer/manufacturer.
On this basis +-70Vdc (2*50Vac) is far too high.
I would expect somewhere between +-60Vdc to 65Vdc to achieve your 300W into 4ohm. Try to find a pair of 2*45Vac 500VA transformers. If 45Vac are not available, it is easy to add extra windings to the secondaries to achieve the higher voltage. An advantage in adding extra turns is that the thicker wire in a 40Vac with the extra turns will have a slightly lower Isquared R loss than a plain 45Vac 500VA.

As an aside, the peak current into 4ohms is about 12.2Apk. I recommend +-2mF per Apk for your main smoothing capacitors. This requires +-25mF 75V per channel. If you use 40Vac then 63V caps will just do. Personally I would use +-3mF/Apk/channel