PeeCeeBee V4H GB

[Medisinmannen]

For comparison you can see my linear PS with old Hegel(norwegian amp brand) torroid. My cabinet is quite full, and it looks like we have the same from modushop. For my next AB build I will try SMPS. Still have a krell ksa50 to complete tho... 😛

My V4H has been rocking for 1 year (after stability was fixed) and Im very happy with it!

Thank again shaan for sharing your design!

 

[bambadoo]

Looking sharp.
Anyway. My V4h rev1 is now playing wonderfully on both channels.
With +-45V connex smps (x2)

On my test speakers (I guess about 87dB sensitivity). Not a single hiss, thump anything when turning on/off or when idle.

Will test on my main speakers later (around 96dB sensitive).

I tested with scope one channel and it showed almost perfect squarewave up to at least 18khz.

The amp seems very "fast"?

 

[shaan]

🙂 🙂

 

[shaan]

Looking sharp.
Anyway. My V4h rev1 is now playing wonderfully on both channels.
With +-45V connex smps (x2)

On my test speakers (I guess about 87dB sensitivity). Not a single hiss, thump anything when turning on/off or when idle.

Will test on my main speakers later (around 96dB sensitive).

I tested with scope one channel and it showed almost perfect squarewave up to at least 18khz.

The amp seems very "fast"?

It is indeed a somewhat "fast" amp. It is usually very silent in 87dB-ish speakers, however there will probably be some noise in the 96dB speaker.

I see no speaker protection; IMHO it is better to use one even with the friendliest of amps. Better safe...

Bests

 

[ckwong99]

These transistors are usable upto 35V but seems to have a low-ish hFE of 100-200 while the BC pair has around 350. The lower gain may introduce more distortion. Other than that there should be no problem.

Bests.

Thx Shaan your professional comment. I will stick with BC one

 

[bambadoo]

It is indeed a somewhat "fast" amp. It is usually very silent in 87dB-ish speakers, however there will probably be some noise in the 96dB speaker.

I see no speaker protection; IMHO it is better to use one even with the friendliest of amps. Better safe...

Bests

Yes I know about the speaker protection issue. BTW. Have 4 boards of your PSU also and some trannies so I might built linear PSU to see if it has any benefits 🙂

BTW: Mosfet bias is dialed in at 215ma as according to the manual (using 1ohm resistors in series with the psu. )

After 3 hours of playing the amp dont get hot at all. Not even hand warm. (3 u modushop chassis).


Would it be any benefit to juice up the bias some more or should I just chill and relax?
If I should recheck bias, do I have to mount the resistors once more or is it an easier, better way?

 

[shaan]

Yes I know about the speaker protection issue. BTW. Have 4 boards of your PSU also and some trannies so I might built linear PSU to see if it has any benefits 🙂

Okay. 🙂

BTW: Mosfet bias is dialed in at 215ma as according to the manual (using 1ohm resistors in series with the psu. )

After 3 hours of playing the amp dont get hot at all. Not even hand warm. (3 u modushop chassis).

If the heatsinks are cool although bias reads 215mA or more then all is well. The sinks are doing their job well, and their temperature is a function of 1.ambient temperature, 2.radiating surface area and 3.airflow between the fins. If 1 is low, 2 is high and 3 is not facing problem, then the sinks will dissipate the heat quickly and won't get warm.

Would it be any benefit to juice up the bias some more or should I just chill and relax?

If it feels like there's nothing wrong with the sound, like no thinness or fatigue after a hour of listening or no feeling of less definition in high frequency, then sit back and enjoy. 🙂

If I should recheck bias, do I have to mount the resistors once more or is it an easier, better way?

Yes you will have to mount them back. It is not the easier way, but better.

 

[bambadoo]

Thanks for your quick response 🙂

 

[bambadoo]

Ok, testing with my main speakers now.
15inch coax drivers in Onken cabinet. Around 96dB sensitive.
Not a single turn on/off thump. No hiss, hum or anyting. Actually dead silent even putting my ear inside the 15inch woofer to the tweeter. This is really good.

Thanks Shaan for a great product.

 

[shaan]

 

[bambadoo]

Just a quick and small measurements.
1khz, 10khz and 20khz squarewaves into a 6.8ohm load.

Only a 12bit picoscope used.

 

[redjr]

C9 and C10 ??

shaan,

Can you verify if C9 and C10 (V4H) have a voltage rating of 6.3vdc, or is that a typo on the BOM, and should be 63vdc.

 

[shaan]

shaan,

Can you verify if C9 and C10 (V4H) have a voltage rating of 6.3vdc, or is that a typo on the BOM, and should be 63vdc.

Hi.

C9 and C10 are 2200uF 6.3V capacitors, as shown in schematic and BOM.

 

[ckwong99]

Hi Shann, does it a feedback cap help with easy tunning the 0V DC output at SPK ?

 

[shaan]

Hi Shann, does it a feedback cap help with easy tunning the 0V DC output at SPK ?

Yes it does.

The capacitors block DC, so there is only unity gain at DC. Meaning any DC imbalance at the input's upper and lower halves will not be amplified by the amplifier's nominal gain set by the 4k7+100r network. This significantly brings down sensitivity of the output offset voltage towards variations in input offset voltage. This is also why compared to the previous peeceebee versions, v4 and v4h don't require thermal coupling of the input pair to keep output offset under control.

🙂

 

[redjr]

Hi.

C9 and C10 are 2200uF 6.3V capacitors, as shown in schematic and BOM.

Thanks for the clarification. That's what I had ordered.

 

[shaan]

Yup!

V5 coming this summer.

 

[redjr]

V5 coming this summer.

You can't tease us like that shaan and walk away! 😉 Any details? Improvements you can share?

 

[jorgovanko]

Yes... Size of the new PCB will be the same? Mounting holes? Thx

 

[gary s]

Yes shaan, a few details would be nice on your upcoming V5, especially where it might be an improvement on the previous release - or are you thinking of adding more options I wonder.