Hi Shaan,
Would like a pair of each version,V1.1,V2 and V3, if still available.
Thanks for the generous offer 🙂
Would like a pair of each version,V1.1,V2 and V3, if still available.
Thanks for the generous offer 🙂
Hi members.
Important notice:
Because the number of available PCBs is not same for all three versions and I have received more booking requests than the numbers allow, I have temporarily paused sending invoices/PM with payment details for balancing out demand and supply.
As this is a giveaway, naturally these PCBs are available as first-come first-served basis.
Members to whom payment details were sent and payment is still pending, Please Note: Booking will be cancelled if payment is not made within 12 hours from the time this post was created. Cancelled members, if still interested, will have to re-send PM to me for re-joining as long as PCBs remain to be spared.
I will publish updated booked members list, available number of PCBs in all three versions and resume sending PM to interested members from after the aforementioned time.
Important notice:
Because the number of available PCBs is not same for all three versions and I have received more booking requests than the numbers allow, I have temporarily paused sending invoices/PM with payment details for balancing out demand and supply.
As this is a giveaway, naturally these PCBs are available as first-come first-served basis.
Members to whom payment details were sent and payment is still pending, Please Note: Booking will be cancelled if payment is not made within 12 hours from the time this post was created. Cancelled members, if still interested, will have to re-send PM to me for re-joining as long as PCBs remain to be spared.
I will publish updated booked members list, available number of PCBs in all three versions and resume sending PM to interested members from after the aforementioned time.
Giveaway update:
Prasi - 2xV1.1 + 2xV2 + 2xV3 - Booked
avesbilal - 2xV1.1 + 2xV2 + 2xV3 - Booked
Rajesh - 2xV1.1 + 2xV2 + 2xV3 - Booked
CB89 - 2xV1.1 + 2xV2 + 2xV3 - Booked
potepuh - 2xV1.1 + 2xV2 + 2xV3 - Booked
vasillis - 2xV1.1 + 2xV2 + 2xV3 - Booked
Joshvi - 2xV1.1 + 2xV2 + 2xV3 - Booked
Boyet0173 - 2xV2 + 2xV3 - Booked
Sashi - 2xV1.1 + 2xV2 + 2xV3 - Booked
gannaji - 2xV1.1 + 2xV2 + 2xV3 - Booked
Sonal Kunal - 2xV1.1 + 2xV2 + 2xV3 - Booked
🙂
Prasi - 2xV1.1 + 2xV2 + 2xV3 - Booked
avesbilal - 2xV1.1 + 2xV2 + 2xV3 - Booked
Rajesh - 2xV1.1 + 2xV2 + 2xV3 - Booked
CB89 - 2xV1.1 + 2xV2 + 2xV3 - Booked
potepuh - 2xV1.1 + 2xV2 + 2xV3 - Booked
vasillis - 2xV1.1 + 2xV2 + 2xV3 - Booked
Joshvi - 2xV1.1 + 2xV2 + 2xV3 - Booked
Boyet0173 - 2xV2 + 2xV3 - Booked
Sashi - 2xV1.1 + 2xV2 + 2xV3 - Booked
gannaji - 2xV1.1 + 2xV2 + 2xV3 - Booked
Sonal Kunal - 2xV1.1 + 2xV2 + 2xV3 - Booked
🙂
Hello Guys.
I'm currently testing a V3 that during testing I had some wiring issues and my V3 was oscillating.
now the wiring is correct and I got good thd results on 1khz measurements.
However imd of 1k-5.5k and thd measurements of 3khz and 5khz are considerable worse than I expected.
THD:
1khz : 0.007%
5khz : 0.079%
imd:
1k - 5.5k : 0.079%
Tests are against a 4ohms on 5 vpp.
this v3 is running at 28.8v with a vas bias of 18ma and mosfet bias ~120ma
So. What component could make high frequencies to be so bad?
Ps. drivers and mosfets were replaced after the oscillation issue was resolved.
my drivers and bcs are matched under 5% hfe.
I'm currently testing a V3 that during testing I had some wiring issues and my V3 was oscillating.
now the wiring is correct and I got good thd results on 1khz measurements.
However imd of 1k-5.5k and thd measurements of 3khz and 5khz are considerable worse than I expected.
THD:
1khz : 0.007%
5khz : 0.079%
imd:
1k - 5.5k : 0.079%
Tests are against a 4ohms on 5 vpp.
this v3 is running at 28.8v with a vas bias of 18ma and mosfet bias ~120ma
So. What component could make high frequencies to be so bad?
Ps. drivers and mosfets were replaced after the oscillation issue was resolved.
my drivers and bcs are matched under 5% hfe.
Last edited:
Hi Bruno.
From a Class-AB amplifier with around 80dB open loop gain, the 1KHz THD performance seems normal. However, more information is needed for answering your questions about the problematic readings correctly.
What output voltage level did you take the measurements at and what is load resistor value? Can you test the THD and IMD of your signal source and share a couple screenshots of the source FFT?
From a Class-AB amplifier with around 80dB open loop gain, the 1KHz THD performance seems normal. However, more information is needed for answering your questions about the problematic readings correctly.
What output voltage level did you take the measurements at and what is load resistor value? Can you test the THD and IMD of your signal source and share a couple screenshots of the source FFT?
Hey Shaan.
Thanks for the questions.
So I did measure thd of my source :
1khz 0.0038%
imd( 60hz - 1khz ) 0.0081%
I did measure 1k - 5khz imd on other amplifiers using the same PSU the same parameters.
amp1 - 0.0074%
amp2 - 0.014%
the parameters are load of 5 vpp @ 4ohms
So the problem seams to be on my v3.
correction the imd(1khz-5.5khz) of v3 is 0.039%
Thanks for the questions.
So I did measure thd of my source :
1khz 0.0038%
imd( 60hz - 1khz ) 0.0081%
I did measure 1k - 5khz imd on other amplifiers using the same PSU the same parameters.
amp1 - 0.0074%
amp2 - 0.014%
the parameters are load of 5 vpp @ 4ohms
So the problem seams to be on my v3.
correction the imd(1khz-5.5khz) of v3 is 0.039%
Attachments
Interesting. I haven't taken IMD measurement of V3, and your readings make me want to. I got some free time tomorrow and a couple channels, so will check on it myself. 🙂
Thanks for the info.
Thanks for the info.
Hi Bruno. Here it is.
Pic 1 - 1000+5100Hz Source IMD, 0.025%
Pic 2 - 1000+5100Hz V3 IMD, 0.044%
I guess nothing's wrong with your V3. 🙂
Attachments
Hi Bruno.
I have more news, hopefully good.
Changed file playback source from PC to phone which has lower noise floor and also lower THD than my PC's onboard line output, and the graphs changed, significantly! Take a look.
Pic 1 - 1000Hz+5100Hz Source IMD, 0.0039%
Pic 2 - 1000Hz+5100Hz V3 IMD, 0.0047%
I have more news, hopefully good.
Changed file playback source from PC to phone which has lower noise floor and also lower THD than my PC's onboard line output, and the graphs changed, significantly! Take a look.
Pic 1 - 1000Hz+5100Hz Source IMD, 0.0039%
Pic 2 - 1000Hz+5100Hz V3 IMD, 0.0047%
Attachments
Hi Bruno. Please ignore my last messages. Read on to know why.
I spent the whole day to find out why the IMD reading was such unrealistically low in the last measurements as this amplifier, in its default config, simply can't have 0.004% IMD.
Turned out I made a mistake in my measurements; told ARTA to measure for 1000Hz+5500Hz while signal played was 1000Hz+5100Hz. As a result it showed erroneous IMD reading.
The correct readings are attached below. 5VPP into 5R (two 10R in parallel).
Pic 1 - Source 0.021%
Pic 2 - V3 IMD 0.029%
This is a more realistic IMD reading which is also consistent with the design's limits.
I spent the whole day to find out why the IMD reading was such unrealistically low in the last measurements as this amplifier, in its default config, simply can't have 0.004% IMD.
Turned out I made a mistake in my measurements; told ARTA to measure for 1000Hz+5500Hz while signal played was 1000Hz+5100Hz. As a result it showed erroneous IMD reading.
The correct readings are attached below. 5VPP into 5R (two 10R in parallel).
Pic 1 - Source 0.021%
Pic 2 - V3 IMD 0.029%
This is a more realistic IMD reading which is also consistent with the design's limits.
