• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

PeeCeeBee V4H GB

Jump to Latest
#921
delange said:
In the meantime, my second channel is running. During setup I adjusted the mosfet bias to 110 mV across the 1R resistors.
After setup was complete I let the amp warm up again and checked bias current by measuring the voltage across the source resistors. And sure, about 50mA per mosfet.

Distortion measurements are the same as with the 100mA bias current. And the amp spits out 142 watts into 8 ohms just before clipping. Next up listening test: I honestly can't hear any difference between the two setups.
I think I'll bring down the bias current of my first channel too. The amp runs a lot cooler with 50mA bias (per mosfet).

Love the deeper base that the PeeCeeBee amplifier produces!
Click to expand...

Happy to know you liked what was the first of the motives behind designing the two amps - better bass. Thanks for sharing the info.

:up:🙂 :cheers:
 
#923
Hi Shaan !

I'm ready now to start populating my V4H boards (not the V4H Rev1), as I didn't have much time until now to work on this project.
I choose the Exicon option I got from Profusion.
My question is about the Revision 1 Mod option: should I do it or not ? Did you actually hear of people having problems with Exicons ?

Thanks for all

JM
 
#924
J.M.K said:
Hi Shaan !

I'm ready now to start populating my V4H boards (not the V4H Rev1), as I didn't have much time until now to work on this project.
I choose the Exicon option I got from Profusion.
My question is about the Revision 1 Mod option: should I do it or not ? Did you actually hear of people having problems with Exicons ?

Thanks for all

JM
Click to expand...

Hi JM.

You can install the rev1 mod with exicons without any problem. The drain-gate capacitors will now define the mosfets' Cgd and will be almost equal and constant in both polarities when rev1 mod is installed, resulting into better stability. So go ahead. 🙂
 
#927
J.M.K said:
You mean just keep the R27 through R30 t 100ohm resistors,
don't add the 6 47pF/500V and I'll be fine ?

No need to fear for unlikely problem ?

JM
Click to expand...

Those capacitors do not downgrade the performance in any way how I understood and improves stability of the amp why do you want to avoid them?
You get some silver mica quality caps for a couple of Euros and less headache at startup.
Especially if you are not set up with scope to do some measure if there is any oscillation. Of course, if you have a scope and you can measure it that is a different cup of tea.
I use Exicon mosfets, they are very well matched but I still use those caps recommended by Shaan.
All do I did not power my amp yet, I amp planning to do so the next couple weeks. 🙂
 
#928
gaborbela said:
Those capacitors do not downgrade the performance in any way how I understood and improves stability of the amp why do you want to avoid them?
You get some silver mica quality caps for a couple of Euros and less headache at startup.
Especially if you are not set up with scope to do some measure if there is any oscillation. Of course, if you have a scope and you can measure it that is a different cup of tea.
I use Exicon mosfets, they are very well matched but I still use those caps recommended by Shaan.
All do I did not power my amp yet, I amp planning to do so the next couple weeks. 🙂
Click to expand...

OK, I'll do that mod. I do have a good osilloscope, but you never know what could trigger a bad event in the future, better be on the safe side.
Thanks a lot

JM
 
#929
J.M.K said:
You mean just keep the R27 through R30 t 100ohm resistors,
don't add the 6 47pF/500V and I'll be fine ?

No need to fear for unlikely problem ?

JM
Click to expand...

Will exicons be stable without the mod? Probably.
Will exicons be stable with the mod? Definitely.

Install the whole mod, not part of it. 🙂

p.s. the resistors are lower value because the caps were installed. basically, the caps slightly slow down the amp, the resistors slightly speed up the amp. complementary action.
 
#937
I have a bunch of film caps in my parts bin, but they are either too big to fit (ERO) or in bigger values. Can some of this be used in 100nF bypass positions?
 

Attachments

  • Film-caps-.jpg
    Film-caps-.jpg
    384.1 KB · Views: 358
You must log in or register to reply here.
Top Bottom