About three months ago i purchased a commercial ready built Class D amp ( Fatman ) .
It's been working fine until a few days ago. The volume is digital meaning it has a knob that is stepped and clicks with each graduation turning indefinitely . ( not sure if digital is the correct description )
Like most people i have a " sweet spot " for listening levels and it is normally set more or less in the same position within a few clicks depending on the cd " loudness.
In the last couple of days the volume is either noticeably quieter or louder needing about another 180 degree turn of the knob either way to achieve the same volume it used to have at the " sweet spot " .
Nothing else im the system has changed and the cds are old and familiar so it's not a case of loudness from the recordings .
If the amp used a analogue volume pot then it would make sense but i was under the impression that "digital" volumes don't wear like analogue does.
Any advice or suggestions would be appreciated .
It's been working fine until a few days ago. The volume is digital meaning it has a knob that is stepped and clicks with each graduation turning indefinitely . ( not sure if digital is the correct description )
Like most people i have a " sweet spot " for listening levels and it is normally set more or less in the same position within a few clicks depending on the cd " loudness.
In the last couple of days the volume is either noticeably quieter or louder needing about another 180 degree turn of the knob either way to achieve the same volume it used to have at the " sweet spot " .
Nothing else im the system has changed and the cds are old and familiar so it's not a case of loudness from the recordings .
If the amp used a analogue volume pot then it would make sense but i was under the impression that "digital" volumes don't wear like analogue does.
Any advice or suggestions would be appreciated .
Those type of controls are called rotary encoders. They haven't a start and end point, they just generate a signal that the unit interprets as up or down for as long as the control is turned.
Is there a preset memorized volume that could have been altered ?
Nothing wears out as such although that doesn't rule out changes in the system control giving different perceived results with rate of change of volume as the control is turned etc.
Is there a preset memorized volume that could have been altered ?
Nothing wears out as such although that doesn't rule out changes in the system control giving different perceived results with rate of change of volume as the control is turned etc.
Thanks for reply ... no no memory or display indicator just a white line on knob i always reduce volume before turning off cause the caps dump lots of noise . So for example at turn on the volume is a minimum with the white line at 6 o'clock . Since i have had it normally i have to turn a fulll 360 plus another quarter turn to get the volume i normally listen at . Now at that setting the volume is either quite a lot louder or a lot quieter , other times it works as it always has at that setting.
The amp itself works as normal other than this sudden change .
The amp itself works as normal other than this sudden change .
I've no answer to that I'm afraid.
With a rotary encoder there are no external reference points. If something has genuinely changed then its going to be down to some software/firmware issue or glitch. It would have to be compared to the manufacturers specification for seeing how the rate of gain changes vs the rate and speed of rotation of the control.
With a rotary encoder there are no external reference points. If something has genuinely changed then its going to be down to some software/firmware issue or glitch. It would have to be compared to the manufacturers specification for seeing how the rate of gain changes vs the rate and speed of rotation of the control.
Thanks for the reply at least i have learnt something new 🙂 I have emailed the supplier i purchased it from but being Amazon and over 3 months i'll be lucky to get any help despite having a 12 mth manufacturer's warranty. From what i have gathered Fatman are bankrupt and the Amazon sellers are just shifting remaining stocks. Pretty poor for an amp that originally had a GBP250 r.r.p. to be honest.
Maybe a debounce problem from a poor design? Try turning it slower even if you think you already do turn it slowly.
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I investigated rotary encoders now i know what they are called and they seem to give a lot of problems the most common being volume decreasing when turning up and down when up.
Debounce issues are mentioned a lot , i also saw how cheap these are to buy i'll try it later and spin it as slow as i can but being stepped with a click on each tiny increment i guess theres a limit to the speed they react at ? The way it looks at the moment i purchased a 20 pound amp with a 250 pound price tag .
A guess it gives me an excuse to buy a new amp though 🙂
Debounce issues are mentioned a lot , i also saw how cheap these are to buy i'll try it later and spin it as slow as i can but being stepped with a click on each tiny increment i guess theres a limit to the speed they react at ? The way it looks at the moment i purchased a 20 pound amp with a 250 pound price tag .
A guess it gives me an excuse to buy a new amp though 🙂
Most probably you have to take off the cover to debug the volume control. Why not to do it now? Unless you have some kind of guarantee and want to activate it...
So you can take some photos in and outside, upload here, this way we can have some chance to get information. Maybe you have to replace the encoder, or only to mount 2 capacitors between the legs... maybe there is a contact error or bad soldering, it's impossible to tell without closer investigation.
20 pound amp? Is there such thing? A moderately good chassis can cost this much or 3 times more...
So you can take some photos in and outside, upload here, this way we can have some chance to get information. Maybe you have to replace the encoder, or only to mount 2 capacitors between the legs... maybe there is a contact error or bad soldering, it's impossible to tell without closer investigation.
20 pound amp? Is there such thing? A moderately good chassis can cost this much or 3 times more...
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Many encoders have the same or similar footprint. You may be able to find a good quality compatible one at Alps.
The amp is only 3 months old and has a one year warranty so i don't want to start messing with it just yet. I' m currently waiting for a response from the seller.
With regard to my 20 pound amp remark ... i was half joking along the lines of it having the tech and build of a a cheap class D from China hidden inside a smart expensive box and from what i've learnt about Fatman products since purchasing probably not far from the truth 🙂
This is what happens when i let my heart rule my head and buy a " style " product .
With regard to my 20 pound amp remark ... i was half joking along the lines of it having the tech and build of a a cheap class D from China hidden inside a smart expensive box and from what i've learnt about Fatman products since purchasing probably not far from the truth 🙂
This is what happens when i let my heart rule my head and buy a " style " product .
One more question... am i right in thinking ( guided by advice here and google searches about rotary encoders ) that the speed at which this type of volume control is turned can have a big effect on the actual
volume produced at any given indication on the dial ie in my case a white line ? Sorry if a dumb question but until today a knew nothing about these encoders .
volume produced at any given indication on the dial ie in my case a white line ? Sorry if a dumb question but until today a knew nothing about these encoders .
Yes to the above question, although as ever the detail is in the software used.
You might find you can spin the control very quickly using the edge of a finger and see little change in level. Turn it slowly and it increments or decrements much more 'normally' as would a real resistive pot.
You might find you can spin the control very quickly using the edge of a finger and see little change in level. Turn it slowly and it increments or decrements much more 'normally' as would a real resistive pot.
Heh, don't feel bad. 9 years ago I purchased three AudioSource AMP 7T's for nearly $700. They were a closeout deal (for reasons that only became obvious later). All three eventually went up in smoke. Replaced the Tripath modules a few times trying to get them to work reliably but just ended up killing $150 worth of modules. All this time later and they're still sitting on a shelf in my lab as a reminder to think twice before I make another purchase like that again. 😱
Thanks for the help/ advice everyone ... i see Amptastic are back in business and have a batch of Mini 1 's in production ready for sale at end of month ... been tempted ever since i read about them may well be my next amp ,if so i need higher sensitivity speakers... never ends does it 🙂
Can have a big effect, but not neccessarily have. It depends on the realisation much. You can try. Too fast and too slow can also be problematic for different reasons.
* update ... the seller has just emailed offering a brand new replacement with return postage paid via a pdf label . All too often i have read about Amazon third party sellers refusing any help once things past the 90 day period even if they have manufacturer 1/2 year warrantys so nice to find one that honours the guarantee .
I'll probably leave it unopened and sell though , not impressed by the failure after such a short period and i will never buy a amp with rotary encoders ever again . It wasn't until i got it i found out it used them ( tone and source use them also ) as there was nothing on the net anywhere regarding specs.
Anyway lesson learnt , might even venture into tube land for the first time one things for sure it won't be a Fatman 🙂 Anyone tried a Quinpu ? 🙂
I'll probably leave it unopened and sell though , not impressed by the failure after such a short period and i will never buy a amp with rotary encoders ever again . It wasn't until i got it i found out it used them ( tone and source use them also ) as there was nothing on the net anywhere regarding specs.
Anyway lesson learnt , might even venture into tube land for the first time one things for sure it won't be a Fatman 🙂 Anyone tried a Quinpu ? 🙂
Good. Where is DIY, and where is electronics? For how much do you want to sell your amp?
By the way: why do you think it was ClassD?
By the way: why do you think it was ClassD?
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Not sure what your first two questions mean but as for how much i have decided to keep it for the moment (see update 2 below )
As for what makes me think it was Class D ... before purchase i searched the net and emailed Fatman, TL Audio ( parent company ) the distributor named on the website and several other people connected with Fatman products in an attempt to find out more technical specs as beyond 25 w per channel and proprietary electronics approach the valve sound in the sales blurb ( the main indication of it being Class D / Tripath ) there was absolutely nothing about it anywhere to be found . I got no replies and eventually attracted by the style and the discounted price bought it " blind "
Fatman S-State 60 Hi-Fi Valve Amp
( its not valve dont know why it says that )
Specs from manual...
Output power 22 watts per channel @ 10 % THD into 4 ohms
FR 20 Hz-20 KHz +/- 1.5 db
Harmonic distortion 0.5 %
SNR 80 db
Input sensitivity 1.0 v +/- 25 %
It's primary target a " lifestyle " product aimed at i -pod / mp3 users.
I have been using with a Onkyo cd 7030 and Scythe Kro Craft rev B speakers ( which i love ) and for not that much money a very enjoyable and musical little system.
#Update 2 ... so since my previous posts i unplugged the amp from the mains ( first time since purchase )
and left it for 24 hours hoping the magic hi-fi pixies might fix it while i slept and they did 🙂
After reinstalling it i did a bit of experimentation with the speed i turned the volume at.
I had been inclined to spin the first 360 degrees quickly then slower to reach the " sweet spot " .
Now i turn the knob slower and with a steady speed throughout in both directions and find that it produces
a much more consistent volume at any given position on the dial indicated by the line on the knob.
So it would seem the " failure " was me and my lack of knowledge regarding this type of control .
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That's good 
So if it behaves a little differently now, then it sounds like the system control got itself in a knot and needed a hard reset.
So if it behaves a little differently now, then it sounds like the system control got itself in a knot and needed a hard reset.
I remember another thread about power surges where you talked about processors sometimes needing a period to reset after a power surge . Would the bass and treble be controlled with the same processor as the volume or does each control have its own independent " brain " ?
Real pain not having a visual indication of volume it would be nice to see how much power i had left before max. The speakers are around 82 db w /m and the amp i would imagine puts out a max of around 9/10
" clean " watts at 8 ohm . On paper performance should be poor but they play loud enough to upset neighbours with no sign of clipping or distortion even with bass heavy dub . I've set the tones to flat as much as possible by ear. The speakers don't have a x-over just a single cap on the tweeter ,does that make for an easier to drive load ?
Given the style of the amp if i had designed i would have made some sort of vu styled meters that fitted in with the retro look and gave a volume level indication at least.
Real pain not having a visual indication of volume it would be nice to see how much power i had left before max. The speakers are around 82 db w /m and the amp i would imagine puts out a max of around 9/10
" clean " watts at 8 ohm . On paper performance should be poor but they play loud enough to upset neighbours with no sign of clipping or distortion even with bass heavy dub . I've set the tones to flat as much as possible by ear. The speakers don't have a x-over just a single cap on the tweeter ,does that make for an easier to drive load ?
Given the style of the amp if i had designed i would have made some sort of vu styled meters that fitted in with the retro look and gave a volume level indication at least.
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