it is the music that is audible when pot is at min position ( no stray noises) and is barely audible from may be 2 feet away. CD palyer doesnt have a volume control and full signal is available at the pot -in. I decided to leave it be as it is not affecting my enjoyment of this amp in any way.
Today also powered the amp thro the bulb tester and the bulb is glowing at the same intensity as that of yesterday after adjustment (slightly/barely orange on a 60W bulb), so no issues.
I think that means that the common (ground) end of the volume pot. is not connected properly to signal ground. If it were, you should have no audio at all with the pot. in the minimum position.
here is the file that i posted earlier , the pot is wired exactly as per the diagram shown. pin 1 is ground, pin 2 (wiper) is signal- out and pin 3 is signal-in (looking from shaft end-left to right).
OK, the only logical alternative if the pot. grounding is correct (and there is no capacitive crosstalk with loose signal wiring) is that the volume control wiper does not reach zero ohms. I would expect the L & R channels to be a bit different in that case.
Shielded wire is commonly specified for wiring pots to minimize signal bleed (similar capacitive coupling effect to crosstalk). You can use the cable from microphones, good quality braided shield RCA connector leads etc. if it is hard to find.
Shielded wire is commonly specified for wiring pots to minimize signal bleed (similar capacitive coupling effect to crosstalk). You can use the cable from microphones, good quality braided shield RCA connector leads etc. if it is hard to find.
Hi Ian,
Yes I measured the resistances of left and right gangs (pin 1 and 2), its about 1.5 and 1.8 ohms when wiper is at zero position. I will try as per your suggestion of using shielded RCA cable for wiring from pot to PCB (connector to pot is shielded cable)and post here.
regards
Prasi
I have installed shileded cable throughout for signal but no change.
I will try as per http://www.diyaudio.com/forums/soli...ll-sound-even-volume-control-turned-zero.html to see if that is indeed the problem.
Also what is the purpose of 100k resistor across i/p just after connector? Can I remove that and test?
reg
Prasi
I will try as per http://www.diyaudio.com/forums/soli...ll-sound-even-volume-control-turned-zero.html to see if that is indeed the problem.
Also what is the purpose of 100k resistor across i/p just after connector? Can I remove that and test?
reg
Prasi
The 100K resistor at the input is just to ensure the input side of the capacitor does not float at an indeterminate high impedance, particularly if no source is connected. I don't see is doing any harm, if you want to try without it that shouldn't hurt anything especially given that the volume pot is present.
Hi Jason,
to solve the issue of sound not getting attenuated at min volume might basically be due to the wiper to ground resistance of 1.7 ohms. I tried "clean it with WD40 with vigorous rotation" routine but didnt help. so I am getting some step pots , the good supplier actually measured the resistance at zero position and its 0.1 ohms!.
unfortunately, the supplier has only A50K and A100k. is A50K suitable for your version of VSSA? I read you mentioning 20k as a suitable value.
reg
prasi
to solve the issue of sound not getting attenuated at min volume might basically be due to the wiper to ground resistance of 1.7 ohms. I tried "clean it with WD40 with vigorous rotation" routine but didnt help. so I am getting some step pots , the good supplier actually measured the resistance at zero position and its 0.1 ohms!.
unfortunately, the supplier has only A50K and A100k. is A50K suitable for your version of VSSA? I read you mentioning 20k as a suitable value.
reg
prasi
IMO WD40 is Poor at cleaning pots and a Lot of 'other' things too.
Concrete testimony to the Power of Advertising 😉
Try some Iso Alcohol ?
IF dirt in the pot is the issue it will help.
Concrete testimony to the Power of Advertising 😉
Try some Iso Alcohol ?
IF dirt in the pot is the issue it will help.
Hi Prasi,
I like to use the lowest value my source will tolerate, but 50k will be fine. I ran some simulations on various volume pot values and there is really no issue anywhere from 20k to 100k. Use whatever you have or can get that is of a quality you are happy with.
I like to use the lowest value my source will tolerate, but 50k will be fine. I ran some simulations on various volume pot values and there is really no issue anywhere from 20k to 100k. Use whatever you have or can get that is of a quality you are happy with.
And finally success! With a step pot of 50k log, all problems resolved (channel imbalance at low volume, sound at zero position of pot). singer is dead center at all volume settings. Even the slight hum which was audible with ear to tweeters has vanished!.
It only proves that a decent quality step pot (with MFRs and make before break contacts) is way better than premium pots (never going to spend a penny on premium pots again!).
Thanks you Jason for all the support
. I really enjoyed the build.
Last edited:
Thanks for the feedback Prasi. I keep meaning to get some of the stepped attenuators to try myself, perhaps it should s time to seek some out.
Hi All,
Just an update here. The amp is in service on my main speakers for almost a month now for atleast an hour or two each day (on an average). I have a feeling that sound has improved. I dont know if its just brain psychology, but I feel that the bass has improved and also the mids and treble are more mellow.
has anyone experienced this?
reg
prasi
Just an update here. The amp is in service on my main speakers for almost a month now for atleast an hour or two each day (on an average). I have a feeling that sound has improved. I dont know if its just brain psychology, but I feel that the bass has improved and also the mids and treble are more mellow.
has anyone experienced this?
reg
prasi
What I have found is that as time passes I become less critical of how the amp sounds and more appreciative of the wonderful musical content. An amp like the VSSA is a huge help in that endeavor.
I am completely sold out. It has been on the back-burner of late but I still want to finish my next iteration. I will be sure to post when ready.
anywhere from 20k to 100k.
Hallo Jason, MM- Patrick, Prasi. and other Enthusiasts.
Thanks Patrick sold me generously his last boards i could now also finish one of
Jasons Amps last days.
First short Test was done late night with CT225 (Cheap Trick Speaker form
German DIY Magazin) with 100k pot and ended with an "aha"- impression.
The PSU is self wired Mr. Evil/PMI Cap Multiplier- nice regulated PSU!, gives it any news whereabouts PMI today?
After bad wiring transformer wire between speaker wire, gives slight hum- so
bad test Szenario!- i started my second test yesterday.
In use is:
http://fostexinternational.com/docs/speaker_components/pdf/FE126En.pdf
These Partnership blows also up my mind, like Jason wrote earlier to his TO-3
version.
The FE126is a real Diva, it needs a R-C-L correction 4,7R+4,7µ(DME,MKP+PIO)+0,82mH air gap, all parallel on + wire and bit dumping in
horn cabinet filled behind speaker.
lock here:http://www.youtube.com/watch?v=OKuzYr1WqL8- nice work with
music.
The VSSA plays really remiss the Fostex, very impressing, long time search could end here- but so many other delicate stuff to do.
If i look to still4given works out so many and:
that is a real applicable given comment.
For prasi, also Jason: i am also on same search, right positioned pot.
Actually the Amp is used with simple 50k mono pot- and i feel it is in right
dimension.
The Input Cap(DME- PP+ Pio 40U-9) i have seen in still4given- terry's pictures and also N. Pass used them, so i teste it out- nothing wrong- very nice tonality.
This combination goes in my range.
I'm on the way now to etch my own shaan PiCiBi Board- John Bali version, to
build the simple without ccs, to find out the different.
Jason was amazed about TO-3 with genuine SK135/SJ50- that in mind-
all time on search.
Now some testcase, only pics.
I would also count in if Jason finished next time new boards.
The Amp is to good to only have ONE!
Best Regards, enjoy listening Music.
Bangla 50+.
P.S. yesterday i found from xrk971:"I was having temporary senior moments.", that sounds to good not to share.
Hallo Jason, MM- Patrick, Prasi. and other Enthusiasts.
Thanks Patrick sold me generously his last boards i could now also finish one of
Jasons Amps last days.
First short Test was done late night with CT225 (Cheap Trick Speaker form
German DIY Magazin) with 100k pot and ended with an "aha"- impression.
The PSU is self wired Mr. Evil/PMI Cap Multiplier- nice regulated PSU!, gives it any news whereabouts PMI today?
After bad wiring transformer wire between speaker wire, gives slight hum- so
bad test Szenario!- i started my second test yesterday.
In use is:
http://fostexinternational.com/docs/speaker_components/pdf/FE126En.pdf
These Partnership blows also up my mind, like Jason wrote earlier to his TO-3
version.
The FE126is a real Diva, it needs a R-C-L correction 4,7R+4,7µ(DME,MKP+PIO)+0,82mH air gap, all parallel on + wire and bit dumping in
horn cabinet filled behind speaker.
lock here:http://www.youtube.com/watch?v=OKuzYr1WqL8- nice work with
music.
The VSSA plays really remiss the Fostex, very impressing, long time search could end here- but so many other delicate stuff to do.
If i look to still4given works out so many and:
HTML:
What I have found is that as time passes I become less critical of how the amp sounds and more appreciative of the wonderful musical content. An amp like the VSSA is a huge help in that endeavor.that is a real applicable given comment.
For prasi, also Jason: i am also on same search, right positioned pot.
Actually the Amp is used with simple 50k mono pot- and i feel it is in right
dimension.
The Input Cap(DME- PP+ Pio 40U-9) i have seen in still4given- terry's pictures and also N. Pass used them, so i teste it out- nothing wrong- very nice tonality.
This combination goes in my range.
I'm on the way now to etch my own shaan PiCiBi Board- John Bali version, to
build the simple without ccs, to find out the different.
Jason was amazed about TO-3 with genuine SK135/SJ50- that in mind-
all time on search.
Now some testcase, only pics.
I would also count in if Jason finished next time new boards.
The Amp is to good to only have ONE!
Best Regards, enjoy listening Music.
Bangla 50+.
P.S. yesterday i found from xrk971:"I was having temporary senior moments.", that sounds to good not to share.
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