Thanks for posting that snippet, Sakis. I used my magnifying glass to read the schematic but sure enough, regulated 35V to the bootstrap voltage divider, which is just 5V above the supply rail. Perhaps the regulated DC potential gave better results in that design? The emitter resistor for the VAS transistor is only 33R, about as close as you would want to be to be to the -ve rail.
They seem to have really tried to get maximum 8R power from 30V rails here. I wonder if it was worth it?
It could be almost any reason. Let's say that you have 5000 transformers sitting in a warehouse, but the output is just a volt or two below what you need...
Member
Joined 2009
Paid Member
Kind regards
Sakis
I also don't quite get this youtube thing where people suggest you get listening impressions of their gear over the net...
I also don't quite get this youtube thing where people suggest you get listening impressions of their gear over the net...
Right . How do they manage that ? There seem to be many guys who put up such video's . Some even wanting to show bass performance !!
P3A
Uploading a video on youtube i know that sound is converted in MP3.
This is catastrophic for sound quality but is the only way for some,in the other side of the world ,to hear and know that is a functional amplifier.
I don't want to sell nothing .
I don't want to make money from this.
I make any amplifier just for me.
Regards.
Right . How do they manage that ? There seem to be many guys who put up such video's . Some even wanting to show bass performance !!
Uploading a video on youtube i know that sound is converted in MP3.
This is catastrophic for sound quality but is the only way for some,in the other side of the world ,to hear and know that is a functional amplifier.
I don't want to sell nothing .
I don't want to make money from this.
I make any amplifier just for me.
Regards.
Sorry thimios , don't take this personally. I didn't specifically refer to your youtube video.
I just wondered how anyone could guess how 'anything' sounded over a youtube video.
In your case maybe you should just say 'please watch my 'xxx amp' functioning on 'so and so' link. That would give you the exposure you want .
Cheers.
I just wondered how anyone could guess how 'anything' sounded over a youtube video.
In your case maybe you should just say 'please watch my 'xxx amp' functioning on 'so and so' link. That would give you the exposure you want .
Cheers.
@Ian ...
If you use a magnifying glass you may also notice that there is a click in the picture to enlarge it !!! Still i don't think that this has to do anything with power is got to be something related to the sound quality I still have the amp under repair (tuner issue ) and i may as well measure performance as is and then again with the bootstrap tied to the rail and see .
@PMI
It doesn't work like that for the Japanese of that era it is got to be other reason the 35 V rail is used inside the amp for the RIAA tone control and tuner ( most amplifiers of that series work like that more than 25 models ) still this is the only one with that function
@BiGUN
Gareth sorry but no ALSO the Japanese of that era where very specific and never hide behind ""fake" or commercial specs on the contrary specs often was underestimated and the actual result was just a bit better
@Stuey+ashok
yeap i thing Uncle Charlie invented that with the Dx amplifiers and now we are all infected with this rather stupid approach I always follow uncle Charlie's subjects since these are highly populated and there is going to be always something to learn from there but never watched a video ...
Thimios ...relax this is a very friendly forum and this is a twice as much friendly thread ...nobody accused you of anything ( like making money or so) here is a bunch of people enjoying audio . Your video was very nice showing the job you done ( especially because it DOESN'T include a two hours speech inside ) but it can tell us absolutely nothing about the sound quality ( as also pointed by other members )
On the other side your scope readings and measuring is by far more useful as a reality test Try in the feature to make some tests with capacitive/resistive loads which is a thing that might also provide info about the stability and tolerance of the amp in a reactive load .
Happy regards
Sakis
If you use a magnifying glass you may also notice that there is a click in the picture to enlarge it !!!
Still i don't think that this has to do anything with power is got to be something related to the sound quality I still have the amp under repair (tuner issue ) and i may as well measure performance as is and then again with the bootstrap tied to the rail and see . @PMI
It doesn't work like that for the Japanese of that era it is got to be other reason the 35 V rail is used inside the amp for the RIAA tone control and tuner ( most amplifiers of that series work like that more than 25 models ) still this is the only one with that function
@BiGUN
Gareth sorry but no ALSO the Japanese of that era where very specific and never hide behind ""fake" or commercial specs on the contrary specs often was underestimated and the actual result was just a bit better
@Stuey+ashok
yeap i thing Uncle Charlie invented that with the Dx amplifiers and now we are all infected with this rather stupid approach I always follow uncle Charlie's subjects since these are highly populated and there is going to be always something to learn from there but never watched a video ...
Thimios ...relax this is a very friendly forum and this is a twice as much friendly thread ...nobody accused you of anything ( like making money or so) here is a bunch of people enjoying audio . Your video was very nice showing the job you done ( especially because it DOESN'T include a two hours speech inside ) but it can tell us absolutely nothing about the sound quality ( as also pointed by other members )
On the other side your scope readings and measuring is by far more useful as a reality test Try in the feature to make some tests with capacitive/resistive loads which is a thing that might also provide info about the stability and tolerance of the amp in a reactive load .
Happy regards
Sakis
P3A
Ok ashok don't worry...alll under controll.
Soon P3A(functioning) on youtube
Sorry thimios , don't take this personally. I didn't specifically refer to your youtube video.
I just wondered how anyone could guess how 'anything' sounded over a youtube video.
In your case maybe you should just say 'please watch my 'xxx amp' functioning on 'so and so' link. That would give you the exposure you want .
Cheers.
Ok ashok don't worry...alll under controll.
Soon P3A(functioning) on youtube
Last edited:
Yes, also possible if the 35V supply is lower noise than the +ve rail. A simple design can be noisy due to poor PSRR and filtered rail supplies (e.g. R765/C719) can be of some benefit. The problem is, this reduces the available power but separate supplies for the front end are too expensive so just tapping into a free, higher supply for the +ve rail seems like a good idea. It might also avoid clipping/linearity problems and that should be easy enough to see with the 'scope.
I don't suggest I know why this choice was made but as PMI points out, there could be any of several reasons, though I also doubt the excess stock issue when in that period, production volume would be in the 100s of thousand units. My guess is that it's still just the designer taking an easy opportunity to have a clean, higher voltage VAS supply. It might be interesting to compare with similar, basic Marantz amplifiers to see their bootstrap supply. So then, what model Marantz is it?
Re: Youtube audio.
Anyone who imagines that this audio is even up to MP3 standard is nuts. When I see adults complimenting each other on their sound systems seen this way, it's obvious this has nothing to with audio quality - even great gear that you know sounds good live, usually sounds like total crap even because of the microphone, background noise etc.
This is about pictures, moving pictures with any quality of sound, just to make the experience like being there, proving that something exists and works as we watch the speaker cones move etc. Some guys just feel more engaged by images, particularly now that we live in a world where AV systems rule and electronic visual aids are almost an integral part of personal communication.
'Shame about the reason we try to build better audio systems though, as Youtube also just makes us look like incompetent fools, fawning over awful or very ordinary sounding equipment, as a friend of mine recently pointed out, in between much laughter.
Member
Joined 2009
Paid Member
I have to tell you a weird thing happened to me on this topic. About a year (or two?) ago somebody posted a Youtube link to a comparison between a solid state amp (a vintage design but reasonably well executed) and a tube amplifier. Like you I thought it a waste of time but I listened to it all the same. Well I was shocked to be able to hear a difference and the same difference as most others watched the video. It was a subtle difference, one I couldn't put into words. The one amplifier was clearly more pleasing to my ears although I couldn't describe why. It was something I was sensing at a 'high level'. It was repeatable.
I think the ear-brain is a remarkable thing - perhaps it can extract from poor replay more information than we realize. In this case it was a comparison and so my ear-brain had the opportunity to filter out the 'common mode' crap of Youtube distortions. Perhaps. Who knows. It was an interesting observation at the time.
You heard a difference because both amps were played in the same video. What you didn't hear was 'exactly how' each amp sounds on it's own. If a difference is there, no matter what the MP3 processing did, there is a good chance you can hear a difference. But I'd think it's VERY unlikely that you heard the difference 'as it really is' ! I guess you get my point !
Nice vid. Clean and dynamic sound. Bass seems powerful. How does it compare with your other amps?