Not necessarily, the measured 50Hz peak could simply be a measurement artefact rather than being something that the amplifier actually suffers from.
I will say again NO hum/buzz even if you come very close to the speaker.
Terry - Great American DIY audio-er
So true.
I can't understand why you are so glad when we have some troubles.
I can't understand why you are so glad when we have some troubles.
thimios,
I think LC likes to see his VSSA creation appreciated and I don't think he relishes the trials and tribulations of others. We are all experimenting and learning together here but sometimes thing don't go to plan. I appreciate your enthusiasm and pioneering spirit so don't be upset, keep building and dothe show and tell.
Terry,
Holy stacks of stuff...I'm jealous.
I have boards coming. I plan to use a stereo pair to drive the woofers in my OB set up. The load will be 4 ohms. This amp will go in place of a crown ce2000...big shoes to fill. I think I will need all the output pairs available as well as a large power supply. Time will tell.
Evan
Holy stacks of stuff...I'm jealous.
I have boards coming. I plan to use a stereo pair to drive the woofers in my OB set up. The load will be 4 ohms. This amp will go in place of a crown ce2000...big shoes to fill. I think I will need all the output pairs available as well as a large power supply. Time will tell.
Evan
Hi Evan,
You may be right. My JBL's are apparently easy to drive because even Jason's VSSA with a +-25vdc SMPS is very impressive. I will have to start including some different speaker combinations in some of these listening tests. I have a few different nearfields and some bookshelfs as well. Maybe with tougher loads it will separate the amps a little more.
I'm attaching the pic with some labels on some of the amps I've built. I know diamond plate is not for everyone but I think it's purdy.
You may be right. My JBL's are apparently easy to drive because even Jason's VSSA with a +-25vdc SMPS is very impressive. I will have to start including some different speaker combinations in some of these listening tests. I have a few different nearfields and some bookshelfs as well. Maybe with tougher loads it will separate the amps a little more.
I'm attaching the pic with some labels on some of the amps I've built. I know diamond plate is not for everyone but I think it's purdy.
Attachments
Last edited:
Exactly.
The issues I described above don't usually present themselves as hum anywhere, it's all internal to the amplifier itself.
That said, if you're not getting any hum from the amp in normal use and the spikes only appear on the FFT when connected to the computer, then it will be a ground loop that causes it. A loop that only exists when the amplifier itself is connected to the computer.
It isn't easy to get good measurements from a PC unless you have isolated gear. My amplifiers have ground loop breaker circuits and the computer is galvanically isolated from the signal source. This, in general, keeps ground loops to a minimum, where if the galvanic isolation wasn't present the measurements would be screwed up (I know this because the isolator was put there specifically to break this loop). USB powered sound cards, connected to battery powered laptops, are often the easiest way around this. But certainly not an option really unless you already own a laptop.
I can't understand why you are so glad when we have some troubles.
Hi thimios
I meant from the bottom of my heart, truly admiring to Terry of what he achieved.
I apologize to be misunderstood.
Subjective banter ??
(below) are 2 more .lay's for JK to make pretty.
Current mirrors are face to face - but the same as the one thimios built
(they work).
(AND I already am working on 3 more) ... CFA was just a experiment.
VFA is the way.
PS - when I build , I bet I could get the "spooky" to beat em' all.
Edit - what I mean about the heading .... The EF3 would likely sound different
on both pairs of my speakers (missions or AV123's) , some IPS would be best
on my tangband subwoofer .The speaker/ops/ips combo is what ultimately determines SQ.
OS
(below) are 2 more .lay's for JK to make pretty.
Current mirrors are face to face - but the same as the one thimios built
(they work).
(AND I already am working on 3 more) ... CFA was just a experiment.
VFA is the way.
PS - when I build , I bet I could get the "spooky" to beat em' all.
Edit - what I mean about the heading .... The EF3 would likely sound different
on both pairs of my speakers (missions or AV123's) , some IPS would be best
on my tangband subwoofer .The speaker/ops/ips combo is what ultimately determines SQ.
OS
Last edited:
sorry my point being at -54dbv it would be at an audible level so if there is no hum, the issue is on the input side of the sound card. This is 100% a low level grounding issue. Having said that it probably wont shift the THD results much.
Last edited:
Thank you, sir OS. The Spooky Leach is next on my hit list, but am not sure if the Wolverine or Symasui should come after that. Anyway I'm hoping to pull the trigger on a new IPS in a week or so.
That said, is there any interest in a different number of outputs for the OPS in addition the the five pair ones? Post your suggestions please...
That said, is there any interest in a different number of outputs for the OPS in addition the the five pair ones? Post your suggestions please...
Luxifer ....
No problem , JK ...
Might bring back the "mighty" luxman 120a (below 1/2).
REAL FET input pair ... I think I need more CLG.
This was my first hawksford ... it sure sounded good 5 years ago.
I'll keep it simple and try to find a easily sourced fet w/good specs.
OS
No problem , JK ...
Might bring back the "mighty" luxman 120a (below 1/2).
REAL FET input pair ... I think I need more CLG.
This was my first hawksford ... it sure sounded good 5 years ago.
I'll keep it simple and try to find a easily sourced fet w/good specs.
OS
Attachments
So in your opinion, going for a CFA is a waste of time? Or did I misunderstand your comment?
It would seem that most of the VFAs do offer superior numbers.
Member
Joined 2009
Paid Member
What I can say is that my TGM7 (high CLG) which can be built as CFA or VFA was first built in VFA form. It sounded so darn good I never got around the CFA version. Actually, I was hoping Fab or somebody would try it - I don't appear to have the time or focus that Terry has to spend on building !
You only wish. It's actually vice versa.
Who's experiment?
You said you'll make one and compare ... so it was a prank.
Other peoples experiments. Even as I am designing them , I sit on the "sidelines"
..watching the builds and impressions.
I can't afford to build multiple amps like terry . Only one chance ...
So , I had to find a way to make my hobby affordable (modular). I shared
it in the hopes of others to do the real building (since I can't afford it).
I am glad no one was "exploded" or was stuck with a "bomb".
At least I know my 1 chance at an amp will be successful.
Unlike you... my motives are not $$$ , LC .
5'th ... I do not say CFA is a worthless endeavor , but is just an alternative
to VFA.
Edit - #'s are not everything !
!
My CFA/VFA comparisons will be far more objective. I'll try both on my
multiple sets of audiophile full range speakers and as a sub driver.
This is what I've spent my $$ on since Xmas - speakers (and found 2
receivers - the H/K and sansui)
If I can not perceive a great difference , I will tell it "as so".
PS - I not $$$ rich like y'all , My software is stolen , my PC's and trafos
are from the dumpsters (I do now have everything for 4 complete amps
still need heatsinks ).
Hopefully , by next Xmas ... i'll have a DIYA amp running all my new speakers.
OS
..watching the builds and impressions.
I can't afford to build multiple amps like terry . Only one chance ...
So , I had to find a way to make my hobby affordable (modular). I shared
it in the hopes of others to do the real building (since I can't afford it).
I am glad no one was "exploded" or was stuck with a "bomb".
At least I know my 1 chance at an amp will be successful.
Unlike you... my motives are not $$$ , LC
.5'th ... I do not say CFA is a worthless endeavor , but is just an alternative
to VFA.
Edit - #'s are not everything !
!
My CFA/VFA comparisons will be far more objective. I'll try both on my
multiple sets of audiophile full range speakers and as a sub driver.
This is what I've spent my $$ on since Xmas - speakers (and found 2
receivers - the H/K and sansui)
If I can not perceive a great difference , I will tell it "as so".
PS - I not $$$ rich like y'all , My software is stolen , my PC's and trafos
are from the dumpsters (I do now have everything for 4 complete amps
still need heatsinks ).
Hopefully , by next Xmas ... i'll have a DIYA amp running all my new speakers.
OS
Keep the OPS the way it is ... man !!!
I'm only going for 3 pair , the 5 pair PCB will do both 3/5 (or even 2) , it's just
35mm longer than the "slewbaby".
Still4givens build is the "most purdy" OPS i've seen on the forum or ebay.
The next "stuff" should be - power supply /softstart ... and
a REAL good overcurrent/DC protect offering.
OS
I wouldn't go saying that lots of us are rich, we're building stuff for a reason too
I shall stick with the CFA-XH and see how it performs. (I currently have a TPC blameless CFP and they are no slouch performance wise.)
As it happens my wolverines were made with 95% recycled parts.
As a question though. If this has been posted somewhere then I apologise for asking, but the CFA-XH what exactly is its midband, ie 1kHz, distortion performance like?
I know you've posted lots of high frequency Fourier analyses, but don't remember seeing any low frequency ones.
I shall stick with the CFA-XH and see how it performs. (I currently have a TPC blameless CFP and they are no slouch performance wise.)
As it happens my wolverines were made with 95% recycled parts.
As a question though. If this has been posted somewhere then I apologise for asking, but the CFA-XH what exactly is its midband, ie 1kHz, distortion performance like?
I know you've posted lots of high frequency Fourier analyses, but don't remember seeing any low frequency ones.
Increase the input (or gain) , Terry !
My H/K 680 could "walk all over" that VSSA (52V rails)!!
Reduce those 2 resistors to 56-68R on the CFA-X and the VSSA would
"squeak like a mouse" while the slewmonster roars at 140v p-p
. geez ! He has the power ... but won't let it out
.OS