I wish I could order free time from Mouser along with the rest of my project parts
Whoever figures out how to package and productize 'free' time will be a trillionaire overnight! ha
That's awesome news X, congrats!
I need a few more boards, I ordered some components to make a desktop version, and I would like to build a second 'desktop' version to use as a pre-amp for some upcoming amp builds (vhex, f5tv2, etc).
Best to order them from your etsy shop?
EQ and reverse polarity
So, I setup BRYTT’s EQ filters and/or convolution wav file in JRiver – and it works great for the OB-1's (Post 916). What I do not understand is the importance/use/value of the Reverse Polarity setting. According to BRYTT, when setting up these 25 filters, he recommends (in post 918): “also good idea when at it, to also set a filter that reverse polarity output to correct inverting source follower SE topology”. Does a source follower SE topology amp always reverse the polarity of the output channels? And if so – does it matter to the average man like me, or influence the SQ?
In a simple test last night I played some music in JRiver using the PCA and OB-1’s – and toggled the Reverse Polarity filter on and off while the music plays. I must honestly say that I could not hear a difference, or am I also missing something? I must confess that I fail to understand how software can actually reverse the polarity.
When using only BRYTT’s convolution file in JRiver (no other EQ filters enabled) the OB-1’s sound fantastic, and I am truly grateful to him for sharing that with us. I assume that the polarity is still reversed when only using the convolver – but does not seem to matter.
I am still hoping to get Equalizer APO working correctly for other Windows based music players. I see Equalizer APO can also employ convolution files, but I cannot seem to get it working yet. In Equalizer APO there is no command to reverse the polarity.
So, I setup BRYTT’s EQ filters and/or convolution wav file in JRiver – and it works great for the OB-1's (Post 916). What I do not understand is the importance/use/value of the Reverse Polarity setting. According to BRYTT, when setting up these 25 filters, he recommends (in post 918): “also good idea when at it, to also set a filter that reverse polarity output to correct inverting source follower SE topology”. Does a source follower SE topology amp always reverse the polarity of the output channels? And if so – does it matter to the average man like me, or influence the SQ?
In a simple test last night I played some music in JRiver using the PCA and OB-1’s – and toggled the Reverse Polarity filter on and off while the music plays. I must honestly say that I could not hear a difference, or am I also missing something? I must confess that I fail to understand how software can actually reverse the polarity.
When using only BRYTT’s convolution file in JRiver (no other EQ filters enabled) the OB-1’s sound fantastic, and I am truly grateful to him for sharing that with us. I assume that the polarity is still reversed when only using the convolver – but does not seem to matter.
I am still hoping to get Equalizer APO working correctly for other Windows based music players. I see Equalizer APO can also employ convolution files, but I cannot seem to get it working yet. In Equalizer APO there is no command to reverse the polarity.
Correct polarity simply means diaphragm pushes out corresponding to a pressure compression wave vs a rarefaction wave that happens when diaphragm pulls (sucks in). Byrtt said it probably won't matter on headphones. However, on room speakers it makes a difference for transient perfect speakers and sound kick drums etc. even in room it's a debate. Many people swear a second order crossover with tweeter inverted sounds as good as normal.
Software DSP invert simply makes all positive negative and vice versa.
Software DSP invert simply makes all positive negative and vice versa.
Ok, makes sense - so the +/- signal to the DAC is inverted. Anyway - I could not hear a difference. As long as my amp pumps beautiful music I don't care about reversing.
I just got a set of KZ ZS5 budget quad driver IEM's and gold braided upgrade cables. Dual balanced armature and dual dynamic drivers for under $40. Upgraded braided gold cables were $13. I only got them because my 5yr old Aurvana 3 dual balanced armature IEMs finally broke. Anyhow, playing it through the PCA right now and it's a real eye opener. Amazing clarity and sound stage like a good powerful 4 way speakers with a deep subwoofer. Complex music is made clear and articulate - very nice. I now hear infrasonic content I did not know existed on some tracks, and normallly only heard with big subs. It was quite odd to think I had a HT sub strapped to my head. It's quite a revelation to hear what this amp is capable of. Will listen more but initial impressions are just superb. Reviews say stock cable may have QC issues so I got the upgraded cable which is nice - tangle proof and very supple. The IEM is large but amazingly fits very well and is comfortable as it is very light and angled just right.
Cable:
Cable:
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All of a sudden I'm interested in IEMs for the first time. These look like a great value.
Could flipping the polarity back to normal be accomplished via a layout tweak to a future "Revision 2" PCB that routes the +/- output traces to opposite legs of the output jack?
I don't think I can hear the difference, even with speakers, unless only one driver has reversed polarity, which does weird phase cancellation.
Could flipping the polarity back to normal be accomplished via a layout tweak to a future "Revision 2" PCB that routes the +/- output traces to opposite legs of the output jack?
I don't think I can hear the difference, even with speakers, unless only one driver has reversed polarity, which does weird phase cancellation.
You could do this if the outputs were simply going to speakers with independent wires. However, it's going to headphone stereo jacks with a shared ground. Flipping polarity would mean a shared output from both coupling caps. This can be fixed with addition of another JFET or BJT "phase inverter" for a 3-transistor amp.
Update on the ZS5 IEM. They sound great still and really feel like I am taking some great music capability with me when on the road. Complex orchestral symphonies, and heavy metal now sounds really really good again (in addition to jazz, pop, classic rock).
Update on the ZS5 IEM. They sound great still and really feel like I am taking some great music capability with me when on the road. Complex orchestral symphonies, and heavy metal now sounds really really good again (in addition to jazz, pop, classic rock).
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Final round of my output cap comparisons posted over at the Head-Fi thread.
Spoiler: I love Panny FR!
Spoiler: I love Panny FR!
Thanks for the great review. I just built another amp with the FR 1000uF 25v on the output and no bypass with a 10uF 35v Silmic on on input.
No film caps anywhere.
Listening now and will give impressions later.
New KZ ZS5 IEM'a sound really nice. No problem driving 16ohm
IEMs with 106dB sensitivity.
No film caps anywhere.
Listening now and will give impressions later.
New KZ ZS5 IEM'a sound really nice. No problem driving 16ohm
IEMs with 106dB sensitivity.
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Also prefer post 916 correction from now on after Status Audio sent me new OB-1 full functional left channel : ) actual it looks the test convolution file was only excellent sounding when used on the defect set of cans : (
Regarding inverting signal or not when using PCA myself can't hear the difference in A/B test into OB-1 headphones but point is when we at it using DSP correction then why not correct back to standards. That said for many reasons think PCA should be stamped loud and clear it phase inverts because it can be important for many cases to know about that spec.
Hope you get APO up working sometime down the road.
They sent you a brand new set of cans or just a replacement driver? That was nice of them.
But you are saying you like the stock sound signature better? That's the sound that I liked and reason why I told people to get these phones.
Btw, check out those 4-way KZ ZS5 IEM's- they sound crazy good for $24 from Aliexpress. Get the gold cables while at it.
Original KZ ZS5 2DD+2BA Hybrid HIFI Earphones In Ear DJ Monito Super Bass Earplug Headsets Stereo Surround Earbuds For iPhone-in Earphones & Headphones from Consumer Electronics on Aliexpress.com | Alibaba Group
KZ Cable Gold Plated ZS5 Earphone Line 2pin 0.75 mm 4 core gold plated Cables upgrade Replacement Cable For KZ ZS5 ZS3 earphones-in Earphone Accessories from Consumer Electronics on Aliexpress.com | Alibaba Group
They sent you a brand new set of cans or just a replacement driver? That was nice of them.
But you are saying you like the stock sound signature better? That's the sound that I liked and reason why I told people to get these phones.
Btw, check out those 4-way KZ ZS5 IEM's- they sound crazy good for $24 from Aliexpress. Get the gold cables while at it.
Original KZ ZS5 2DD+2BA Hybrid HIFI Earphones In Ear DJ Monito Super Bass Earplug Headsets Stereo Surround Earbuds For iPhone-in Earphones & Headphones from Consumer Electronics on Aliexpress.com | Alibaba Group
KZ Cable Gold Plated ZS5 Earphone Line 2pin 0.75 mm 4 core gold plated Cables upgrade Replacement Cable For KZ ZS5 ZS3 earphones-in Earphone Accessories from Consumer Electronics on Aliexpress.com | Alibaba Group
Hi X,
Yes they ended up ship me a brand new set of cans because they at present ran out of driver units as a spare part, so ha ha can make me a OB center channel out of the defect sets right channel.
About OB-1 stock sound its much too hot and warm in lows for me, but with post 916 correction curve that transform to Harman curve their performance raise to sky-high in my eyes, also PCA seems happy to feed them but it had probably been even better if they were 250 ohms impedance as you designed for.
Enjoy those multy way devices and thanks sharing they simply looks fantastic and a great value, myself hate XO's and being a 4-way it gets very complicated so i stay out going modern this time and continue in good old full ranger land.
By the way for tech interested below is the new OB-1 cans probed for L/R channel impedance, the two upper ones are with original Litz wire and the about 2 ohms lower one is when mounted with my own 0,37mm diameter tinned solid cobber core.
Attachments
Thanks great sound study there.
Myself is also on low impedance cans in area 32-64 ohms and in that X designed for 250 ohms think down the road will try PCA as desktop version in style of nice build twocents showed at post 625, that should make space to have 5x higher value for output cap so as damping ratio and amplitude response will equal 250 ohm cans, will probably also raise bias because my own distortion test into low impedance was much far from the one at post 1.
Did a impedance study today attached below for Panasonic caps and one small value Elna, they far from linear and relative small values below 6800uF will not make it possible to have amp output impedance specs stay below 2 ohm as is all-round recommended, also amplitude comparison for same values into 50 ver 250 ohms is attached.
