Hi I'm new to this game but here goes.
Have Kenwood 3020SE amp, sounds good but lot of noise, like mains hum, even with no source connected.
Have read various advice on earthing and am very confused.
Why only two core mains lead ie no earth?
(Original) two core mains lead cheap and nasty, so gonna change this, should I use shielded 3 core, connecting the internal yellow/green (earth) wire to the case for safety?
Read that the shield should be left disconnected at the amp end but connected to the earth pin of the mains plug.
Spent ages reading loads of threads and confused, like I say.
Have Kenwood 3020SE amp, sounds good but lot of noise, like mains hum, even with no source connected.
Have read various advice on earthing and am very confused.
Why only two core mains lead ie no earth?
(Original) two core mains lead cheap and nasty, so gonna change this, should I use shielded 3 core, connecting the internal yellow/green (earth) wire to the case for safety?
Read that the shield should be left disconnected at the amp end but connected to the earth pin of the mains plug.
Spent ages reading loads of threads and confused, like I say.
noise
Are you getting the noise/hum all the time signal in or not?
If you have humm constantly being an OEM amp I would think you have a bad diode in the power supply,capacitor, or regulator.
Are you getting the noise/hum all the time signal in or not?
If you have humm constantly being an OEM amp I would think you have a bad diode in the power supply,capacitor, or regulator.
I used to have one of those, they were nice amps.
I suspect it may not be an earthing problem, (unless someone has been fiddling around inside), rather the PSU caps aging and letting mains hum through. The amp is old enough, especially if it has been well used, to make a complete recap worthwhile.
I suspect it may not be an earthing problem, (unless someone has been fiddling around inside), rather the PSU caps aging and letting mains hum through. The amp is old enough, especially if it has been well used, to make a complete recap worthwhile.
I have one of these amplifiers - they do indeed sound lovely!
I can't really offer any help, as I've been unable to find a service manual for the KA-3020SE. But I have recapped the power amplifier section - when it wasn't screwed down to the chassis(initial testing after swapping caps), the amount of noise passed down to the speakers was truly horrible. My advice would be to pull the case, and try tapping around the screws and the grounding point near the relays - the black wire that comes to the front of the chassis.
Failing that, it'll be time to start looking at replacing capacitors. I changed everything apart from the 10,000uF Elna PSU caps. Using a mixture of Rubycon ZL and ZA caps, and Panasonic FC caps - because the ZL and ZA range isn't terribly great for some values. I also bypassed a lot of them with 0.1uf polypropylene - the whole lot came to under £10, and is highly recommended.
Failing that, convert it into a Gainclone? You've got a nice PSU inside, can scavenge the 6A rectifier - and you've then got 35v+/-. A lovely passive pre-amp when the source direct feature is enabled, and a huge heatsink. Should make for a cheap experiment! I thought about doing this when the amplifier sounded totally awful after recapping - but after 20-30 minutes use, it sounded lovely again, so never investigated further. 🙂
--Rich
I can't really offer any help, as I've been unable to find a service manual for the KA-3020SE. But I have recapped the power amplifier section - when it wasn't screwed down to the chassis(initial testing after swapping caps), the amount of noise passed down to the speakers was truly horrible. My advice would be to pull the case, and try tapping around the screws and the grounding point near the relays - the black wire that comes to the front of the chassis.
Failing that, it'll be time to start looking at replacing capacitors. I changed everything apart from the 10,000uF Elna PSU caps. Using a mixture of Rubycon ZL and ZA caps, and Panasonic FC caps - because the ZL and ZA range isn't terribly great for some values. I also bypassed a lot of them with 0.1uf polypropylene - the whole lot came to under £10, and is highly recommended.
Failing that, convert it into a Gainclone? You've got a nice PSU inside, can scavenge the 6A rectifier - and you've then got 35v+/-. A lovely passive pre-amp when the source direct feature is enabled, and a huge heatsink. Should make for a cheap experiment! I thought about doing this when the amplifier sounded totally awful after recapping - but after 20-30 minutes use, it sounded lovely again, so never investigated further. 🙂
--Rich
Hi Rich
Interesting ideas. To be honest the amp hasn't had much use due to young family/long work hours over the years so in theory everything should be in good condition.
Embarrassingly I have found the solution to my problem - I moved my old Marantz CD50SE away from the amp and hey presto! the hum disappeared......
So I bought an old CD63KI and modded it....bought a matching PM66Ki and modded it.... and now I realise that when I felt my amp was overbright and a little harsh on the headphones (where I do most of my listening late at night) I realise that the sound is probably due to the opamp in the headphone section
So I dont know whether to mod the 3020SE or go down the gainclone route like you say.
Any ideas how much improvement I could get?
Interesting ideas. To be honest the amp hasn't had much use due to young family/long work hours over the years so in theory everything should be in good condition.
Embarrassingly I have found the solution to my problem - I moved my old Marantz CD50SE away from the amp and hey presto! the hum disappeared......
So I bought an old CD63KI and modded it....bought a matching PM66Ki and modded it.... and now I realise that when I felt my amp was overbright and a little harsh on the headphones (where I do most of my listening late at night) I realise that the sound is probably due to the opamp in the headphone section
So I dont know whether to mod the 3020SE or go down the gainclone route like you say.
Any ideas how much improvement I could get?
No idea. But I run a pair of Sennheiser HD480II-13R headphones from my 3020SE, and think it sounds lovely through them. It doesn't use any opamps, it takes feed directly from the speaker channels. Presumably, it'll just be taking it from the two NEC ICs used for the class A section of the amplifier, at low volumes.
It's a nice sounding amplifier, in my opinion. Should be quite easy to gut and turn into a DIY amplifier, if you really fancy - the preamp is entirely passive when source direct is enabled. Will just be a case of following the traces from the volume pot to the ribbon cable - I think it was 2 pins in the middle. Should be a doddle to do - but I don't know how the gainclones cope with driving a headphone load?
Or, if you wanted to be really flash, build it into a big headphone amp 🙂. Build a cmoy or Pimeta inside the 3020... 😀
--Rich
It's a nice sounding amplifier, in my opinion. Should be quite easy to gut and turn into a DIY amplifier, if you really fancy - the preamp is entirely passive when source direct is enabled. Will just be a case of following the traces from the volume pot to the ribbon cable - I think it was 2 pins in the middle. Should be a doddle to do - but I don't know how the gainclones cope with driving a headphone load?
Or, if you wanted to be really flash, build it into a big headphone amp 🙂. Build a cmoy or Pimeta inside the 3020... 😀
--Rich
Does anyone have the schematic of this popular amp? It would be interesting to know what make this amp sounds so good.
I'm also looking for the schematic Pioneer A400. Appreciate if someone could post the schematic as well. Thanks.
I'm also looking for the schematic Pioneer A400. Appreciate if someone could post the schematic as well. Thanks.
Ipanema said:
I don't, but from what I can figure out from looking over the amplifier, it works something like this:-
Passive pre-amp when tone-defeat enabled - literally from the RCA sockets, through a resistor, to the front-panel PCB selector switches, to the volume pot, to the power amplifier.. When tone controls enabled, it takes the same route, but also goes via the balance, bass and treble pots, and a nasty opamp. Can't remember what it is - probably an NJC4580.
Obviously, there is additional circuits for phono inputs. These are located on the input selector board. Two more NJC4580 opamps are used on these inputs.
For the power amp, I believe it works in two ways. There 2 small NEC class A chip-amps(1 per channel), but I can't remember the part number. This is used at lower power output, and is probably the only part of the amplifier I have heard! 🙂 I'm sure I looked through the datasheet for the IC, and noted it had 50w output. I don't think this is the case in this amplifier, as there is a separate class-B section for when higher power is called for. There are two bias pots, which I assume are for controlling when the switchover takes place on each channel?
The SE had a beefier PSU, but there are no markings to suggest what its capabilities are. I seem to recall either 30v+/- or 35v+/- was available after rectification, and 60v beforehand? Anyway, from the regulator, there are two 10,000uF 42v Elna capacitors, followed by two 1000uF Elna capacitors. In fact, I tend to think that all electrolytics were Elna, but only 2 were from their audio ranges. I guess the nice sound just comes from a rather simple design, half-decent components, and glowing reviews... 😉
All this may not be totally accurate, as it's from memory - and I don't want to start stripping my amplifier down at 4am 😉.
Two sets of speaker outputs are provided, switched by 2 relays. I always thought this was a nice touch at the £200 price-point when new. I didn't have a lot to do with this amplifier when new, but I did work part-time in an audio-visual shop whilst at college. The KA-3020SE was very-much in the same league as the Marantz PM-44SE and the Technics SU-A600/900 IMO, if lacking a little outright power in comparison.
Some pictures of the original KA-3020 can be found here. Whilst somewhat different, it is largely the same
The 3020SE, PM-44SE, SU-A600, 900, and the Pioneer A400 were all the 'killer' amps of the late 1990's. From memory, all sounded very similar - each was extremely capable with all genres of music. I doubt any of them would disappoint most users - some will prefer the tonal characteristics of one, whilst others would prefer a different model. The differences were small IMO - you'd need a rather good pair of speakers to notice anything significant.
The Kenny is the cheapest to get now - mine was £21 + post on eBay. A400 and the Technics amps tend to fetch £60 to over £100. I didn't put much effort into finding a PM-44SE, as there seemed to be quite a few reports of faults.
ETA - I've had no training in electronics, so I might be talking complete tosh. The extent of my capabilities are a logical mind, some experience of soldering through my jobs - I repaired mobile phones for a bit, and spent several years as an IT engineer. Don't take anything I've said as gospel - I have no service manuals for the amp. But it should give a fair idea of how things might work, in the land of Rich... 😉
--Rich
Hi Rich
I bought my Kenny new partly because it was the one to buy at the time.
My PM66Ki cost £70 on eBay in November bought with a faullt -no sound or click from the muting relay on powering up
I had guessed correctly (after reading up on a thread in this forum) that a fuse resistor had blown).
Replaced it with a 13p metal film from Maplin and hey presto! Sweet music and the working Ki's go for about £120.
It was opening it up that got me interested in modding, so I replaced elctrolytics with Black Gates of higher values, Mylar's in the signal chain with equivalent silver mica's and put 100nF and 10nF caps with 1ohm3w resistors across the big PSU caps (some sort of snubber circuit I think).
I did the silver mica's first, which gave a crisper, smooother treble.
The snubbers came next, and I heard details in music I didn't know were there. The Marantz uses 56v 12000uF Elna 'For Audio' caps like the 42v 10000uF in the Kenny.
Only just done the Black Gates so they are still burning in.
The thing that struck me most when I opened up the Kenny last night was the build quality and design layout.
PSU tranny is pretty beefy compared with the toroid in the Ki and the main board layout is so simple, direct and clean with short, straight (and thick) traces. Much better than the Marantz, which has cult status.
Seeing the inside of the Kenny again makes me want to start using it again, so I'm gonna give it a go with the CD63 and see how I get on with it. I'm also waiting for a pair of Grado SR125's which might change my mind a bit. As I recall it was the treble that bothered me before but I recently read an old review which commented on the different treble which might not be to eveyone's taste.
Have to suck it and see, I think.
Good luck with your pc/cdp hybrid project
Jim
I bought my Kenny new partly because it was the one to buy at the time.
My PM66Ki cost £70 on eBay in November bought with a faullt -no sound or click from the muting relay on powering up
I had guessed correctly (after reading up on a thread in this forum) that a fuse resistor had blown).
Replaced it with a 13p metal film from Maplin and hey presto! Sweet music and the working Ki's go for about £120.
It was opening it up that got me interested in modding, so I replaced elctrolytics with Black Gates of higher values, Mylar's in the signal chain with equivalent silver mica's and put 100nF and 10nF caps with 1ohm3w resistors across the big PSU caps (some sort of snubber circuit I think).
I did the silver mica's first, which gave a crisper, smooother treble.
The snubbers came next, and I heard details in music I didn't know were there. The Marantz uses 56v 12000uF Elna 'For Audio' caps like the 42v 10000uF in the Kenny.
Only just done the Black Gates so they are still burning in.
The thing that struck me most when I opened up the Kenny last night was the build quality and design layout.
PSU tranny is pretty beefy compared with the toroid in the Ki and the main board layout is so simple, direct and clean with short, straight (and thick) traces. Much better than the Marantz, which has cult status.
Seeing the inside of the Kenny again makes me want to start using it again, so I'm gonna give it a go with the CD63 and see how I get on with it. I'm also waiting for a pair of Grado SR125's which might change my mind a bit. As I recall it was the treble that bothered me before but I recently read an old review which commented on the different treble which might not be to eveyone's taste.
Have to suck it and see, I think.
Good luck with your pc/cdp hybrid project
Jim
Hiya Jim,
I've read about the treble also. To my ears, it's a nice balance - enough of it to make the sound clear and sparkle, but without ever going over the top. It's just very well controlled, really. With some amplifiers, every time the singer has a sharp 'S' in a word, it sounds horrible - sharp and fake; it can be enough to make you want to turn the music down a smidge. But there is none of that with the 3020SE, it's just nicely controlled and sounds well balanced.
Each to their own though - I think it'll be down to how clear the speakers are, as much as anything. Also, early CD players tended to have a rather sharp treble...
--Rich
I've read about the treble also. To my ears, it's a nice balance - enough of it to make the sound clear and sparkle, but without ever going over the top. It's just very well controlled, really. With some amplifiers, every time the singer has a sharp 'S' in a word, it sounds horrible - sharp and fake; it can be enough to make you want to turn the music down a smidge. But there is none of that with the 3020SE, it's just nicely controlled and sounds well balanced.
Each to their own though - I think it'll be down to how clear the speakers are, as much as anything. Also, early CD players tended to have a rather sharp treble...
--Rich
Hi Rich,
Thanks for the description. What amaze me is that chip amp is use and the reviewer still raving about it. I thought that reviewer will always shun chip amp and prefer discreet design. 🙂
BTW, would you mind finding out which chip amp is use in the Kenwood? Thanks.
Thanks for the description. What amaze me is that chip amp is use and the reviewer still raving about it. I thought that reviewer will always shun chip amp and prefer discreet design. 🙂
BTW, would you mind finding out which chip amp is use in the Kenwood? Thanks.
As promised, the chipamp used in the Class A section is a NEC uPC1298V. I dare say one of the newer chipamps would be better - this dates back to 1986 🙂.
Still sounds pretty good to me though!
Whilst fiddling around, I removed the opamp from the pre-amp tone controls and popped a socket on there. Tried several different opamps - standard was a JRC4565D. Tried several that I have lying around here - JRC4580D, OPA2227, OPA2228, OPA2277, OPA2137.
No matter what opamp was used, there was a slight reduction in tonal dynamics but a HUGE reduction in soundstage. I'd expected the OPA2227 to be a good replacement, with a small but noticeable improvement when using the tone controls. I was half expecting to make a pair of OPA627s fit, and see what they were like.
The 4565D is now back in there. In this circuit, the best opamp by far is no opamp whatsoever. If anyone is using one of these amplifiers, and has adjusted the 'tone' for either their musical preferences or speaker characteristics, I'd urge you to upgrade your speakers. Huge difference. Massive.
For future reference, anyone looking for an amplifier to turn into some kind of Gainclone, the PSU in the 3020SE puts out 45v AC. It's then regulated by RBV-602, down to +/-31v DC.
I might order a pair of LM4870 chips, just to compare. On the other hand, this is already a sweet-sounding amplifier, maybe I should just settle for what I've got, and not let the modding-bug bite me...
Can anyone resist it? 😉
--Rich
Still sounds pretty good to me though!
Whilst fiddling around, I removed the opamp from the pre-amp tone controls and popped a socket on there. Tried several different opamps - standard was a JRC4565D. Tried several that I have lying around here - JRC4580D, OPA2227, OPA2228, OPA2277, OPA2137.
No matter what opamp was used, there was a slight reduction in tonal dynamics but a HUGE reduction in soundstage. I'd expected the OPA2227 to be a good replacement, with a small but noticeable improvement when using the tone controls. I was half expecting to make a pair of OPA627s fit, and see what they were like.
The 4565D is now back in there. In this circuit, the best opamp by far is no opamp whatsoever. If anyone is using one of these amplifiers, and has adjusted the 'tone' for either their musical preferences or speaker characteristics, I'd urge you to upgrade your speakers. Huge difference. Massive.
For future reference, anyone looking for an amplifier to turn into some kind of Gainclone, the PSU in the 3020SE puts out 45v AC. It's then regulated by RBV-602, down to +/-31v DC.
I might order a pair of LM4870 chips, just to compare. On the other hand, this is already a sweet-sounding amplifier, maybe I should just settle for what I've got, and not let the modding-bug bite me...
Can anyone resist it? 😉
--Rich
I wanted to edit my previous post, but I can't see an edit button. Am I missing something here? I hate making another post, as it'll bump the thread to the top of the list...
Anyway, I did some more fiddling with opamps before reassembling. Using headphones, the tonal differences between opamps are bigger than on the speakers. The difference in soundstage was not apparent when using headphones(I've got a pair of Sennheiser HD480II-13R), but the difference in... what do I want to say here? Atmosphere - there was a subtle difference with each amp. Not taking the reduced soundstage or reduced tonal dynamics into the equation, each opamp did add a different atmosphere to the sound. I liked the 2227/8 and 2137 the best, but they were all nasty compared to listening to the source directly. Consequently, I've still put the original 4565D back in. I don't intend on listening through the tone controls, so I figured I may as well keep the others for a better purpose.
I've never really subscribed to such theories, but after tonight I'm going to change my mind. Even when bypassed, the opamp in the tone control circuit is still powered. Changing opamps whilst the amp is powered up(I'm lazy, and with the tone controls bypassed, I figured it'd be dead), the sound of electrical interference was audible when removing and inserting the IC. Even with the IC properly inserted and the tone controls bypassed, noise could be heard through the speakers when the IC was tapped with a screwdriver. Maybe I have a less than great solder joint to the socket(I was pretty careful, so I'm not convinced). Anyway, my point is that the whole tone control circuit could be a possible source of noise - not huge, but certainly audible. Possibly, there would be something to gain by removing the circuit, but this is just speculation.
Replacing the capacitors in the power amplifier section yielded much bigger results than fiddling with the opamp used in the preamp. I used mainly Rubycon ZA/ZL caps, and the sound difference was immediate and distinct. No bad side-effects to report, just a nice upgrade to an already sweet-sounding amplifier.
There is little information on the internet about this amplifier - which is a shame, because it was very highly regarded by the press when released, and it's in plentiful-supply through the usual second-hand channels for very reasonable money indeed. Hence I figured the more I document here, the more chance there is of it helping someone else. 🙂
--Rich
Anyway, I did some more fiddling with opamps before reassembling. Using headphones, the tonal differences between opamps are bigger than on the speakers. The difference in soundstage was not apparent when using headphones(I've got a pair of Sennheiser HD480II-13R), but the difference in... what do I want to say here? Atmosphere - there was a subtle difference with each amp. Not taking the reduced soundstage or reduced tonal dynamics into the equation, each opamp did add a different atmosphere to the sound. I liked the 2227/8 and 2137 the best, but they were all nasty compared to listening to the source directly. Consequently, I've still put the original 4565D back in. I don't intend on listening through the tone controls, so I figured I may as well keep the others for a better purpose.
I've never really subscribed to such theories, but after tonight I'm going to change my mind. Even when bypassed, the opamp in the tone control circuit is still powered. Changing opamps whilst the amp is powered up(I'm lazy, and with the tone controls bypassed, I figured it'd be dead), the sound of electrical interference was audible when removing and inserting the IC. Even with the IC properly inserted and the tone controls bypassed, noise could be heard through the speakers when the IC was tapped with a screwdriver. Maybe I have a less than great solder joint to the socket(I was pretty careful, so I'm not convinced). Anyway, my point is that the whole tone control circuit could be a possible source of noise - not huge, but certainly audible. Possibly, there would be something to gain by removing the circuit, but this is just speculation.
Replacing the capacitors in the power amplifier section yielded much bigger results than fiddling with the opamp used in the preamp. I used mainly Rubycon ZA/ZL caps, and the sound difference was immediate and distinct. No bad side-effects to report, just a nice upgrade to an already sweet-sounding amplifier.
There is little information on the internet about this amplifier - which is a shame, because it was very highly regarded by the press when released, and it's in plentiful-supply through the usual second-hand channels for very reasonable money indeed. Hence I figured the more I document here, the more chance there is of it helping someone else. 🙂
--Rich
Hi Rich
Just read your post.
Interesting point about early CD players and sharp treble. I think that what I thought was sharpness in the amp on the headphones was coming from the old Marantz CD50SE player I had.
Back on topic Brent the Rowemeister from the mammoth CD63 mods thread also has a 3020SE as well as his Marantz PM66Ki's and may fancy modding it. I'm going to post some pics of the internals for him to look at so you never know, we may have a modding thread soon.
Any luck with the PC/CD project yet?
Jim
Just read your post.
Interesting point about early CD players and sharp treble. I think that what I thought was sharpness in the amp on the headphones was coming from the old Marantz CD50SE player I had.
Back on topic Brent the Rowemeister from the mammoth CD63 mods thread also has a 3020SE as well as his Marantz PM66Ki's and may fancy modding it. I'm going to post some pics of the internals for him to look at so you never know, we may have a modding thread soon.
Any luck with the PC/CD project yet?
Jim
Hi Jim,
Still thinking about it. I've kinda lost interest though, for several reasons:-
1. I'm pretty sure I've sussed the problem with my laser printer, so I can have a stab at making my own PCBs. Hence it'll be somewhat easier to start from scratch if I'm not happy with the results. I'm toying with making a simple(ish!) PCM2707 USB adaptor -> AD1896 -> PCM1794, as I already have the 2706/7 here, and a 1794. 🙂
2. Erm, somewhat covered by my previous point - cost. The £30 or so I'd spend getting a 53/63/57/67 cover the cost of a 936a soldering station, some copper-clad board and ferric chloride.
3. Rather than adding an additional box to my already crowded room, I'm somewhat tempted to look at creating an 'all-in-one' box based on modular boards - small gainclone type amplifier and DAC in one box, with a USB interface, and possibly a headphone amplifier. That Texas Instruments sample site has filled my head with all manner of ideas!
The whole idea arose after the brainwave of turning my Xbox into a media centre. Figured it'd be a good way of having all my music/films in one(rather portable) place for when I go visit friends and whatnot - plus, it'd let me have my wonderful music collection at my fingertips without keeping my PC powered up all the time.
Plus, I stumbled across this place whilst browsing this site. Would be a great way to get to grips with everything - slap the ICs on the adaptors and fiddle with breadboard until I found a combination I was happy with, then look at making my own PCBs... 🙂
I'm sounding highly ambitious, for someone who doesn't have a clue what they're doing! 😀
--Rich
Still thinking about it. I've kinda lost interest though, for several reasons:-
1. I'm pretty sure I've sussed the problem with my laser printer, so I can have a stab at making my own PCBs. Hence it'll be somewhat easier to start from scratch if I'm not happy with the results. I'm toying with making a simple(ish!) PCM2707 USB adaptor -> AD1896 -> PCM1794, as I already have the 2706/7 here, and a 1794. 🙂
2. Erm, somewhat covered by my previous point - cost. The £30 or so I'd spend getting a 53/63/57/67 cover the cost of a 936a soldering station, some copper-clad board and ferric chloride.
3. Rather than adding an additional box to my already crowded room, I'm somewhat tempted to look at creating an 'all-in-one' box based on modular boards - small gainclone type amplifier and DAC in one box, with a USB interface, and possibly a headphone amplifier. That Texas Instruments sample site has filled my head with all manner of ideas!
The whole idea arose after the brainwave of turning my Xbox into a media centre. Figured it'd be a good way of having all my music/films in one(rather portable) place for when I go visit friends and whatnot - plus, it'd let me have my wonderful music collection at my fingertips without keeping my PC powered up all the time.
Plus, I stumbled across this place whilst browsing this site. Would be a great way to get to grips with everything - slap the ICs on the adaptors and fiddle with breadboard until I found a combination I was happy with, then look at making my own PCBs... 🙂
I'm sounding highly ambitious, for someone who doesn't have a clue what they're doing! 😀
--Rich
Hi Rich
Cracking ideas.
Considering you say you haven't a clue what you're doing you sound pretty clued up - a damn sight better than me.
Those breadboards look ideal - have you seen the Maplin versions?
Got to get to bed now - builders are up early doors!!!😴
See ya.
Jim
Cracking ideas.
Considering you say you haven't a clue what you're doing you sound pretty clued up - a damn sight better than me.
Those breadboards look ideal - have you seen the Maplin versions?
Got to get to bed now - builders are up early doors!!!😴
See ya.
Jim
Jim,
Any fool can sound clued-up. Read enough datasheets, stroll around the forums for long enough - pick up some ideas and learn the lingo. 🙂
I know absolutely nothing about all this kinda stuff. I have a somewhat logical mind - trained as a plant mechanic in my youth, but have generally worked in IT as a field engineer. Picked up some rather awful soldering skills as a laptop bench engineer, and a short-stint as a mobile phone repair technician.
I have a loose understanding of electronics, and can read the recommended designs in the datasheets. With half-decent tools, I can do a half-decent job. Touch wood, so long as I'm thorough, slow, thorough and thorough with my thoughts, designs, and research, I think I'd be able to cobble something together. Whether it sounded any good would be another matter! But the idea of having everything in one box could help that a lot - I only ever use the PC as a source these days, and the Xbox also supports USB, so it'd be ideal for my needs. If I stuck with TI(the TAS5261 power-amp looks very interesting from a DIY point of view(mono chipamp, 125W at 8ohms with <0.09% THD), the TAS5518 PWM Processor looks devilishly complete and great for upgrading to more channels in future, but rather complicated, but the TAS5012 looks far simpler and would be a good starting point) - everything could be built up on individual boards during testing, and switched to a bespoke PCB once I'd sussed what I was doing. With everything being digital, even I should struggle to harm the sound much... 😉
http://focus.ti.com/docs/prod/folders/print/tas5261.html
http://focus.ti.com/docs/prod/folders/print/tas5518.html
http://focus.ti.com/docs/prod/folders/print/tas5012.html
Seems like a massive task, but it really is quite appealing - avoid the colouration of any opamps in the source, or degradation in sound quality by resampling the sound to a different bitrate, or from interconnects. USB doesn't really suffer from jitter, from what I've read - so many of the big decisions are removed from the plan 🙂.
Of course, the TI chips may sound pants. Technically, they look very nice, but paper-performance doesn't always translate into the real world... 🙂
--Rich
Any fool can sound clued-up. Read enough datasheets, stroll around the forums for long enough - pick up some ideas and learn the lingo. 🙂
I know absolutely nothing about all this kinda stuff. I have a somewhat logical mind - trained as a plant mechanic in my youth, but have generally worked in IT as a field engineer. Picked up some rather awful soldering skills as a laptop bench engineer, and a short-stint as a mobile phone repair technician.
I have a loose understanding of electronics, and can read the recommended designs in the datasheets. With half-decent tools, I can do a half-decent job. Touch wood, so long as I'm thorough, slow, thorough and thorough with my thoughts, designs, and research, I think I'd be able to cobble something together. Whether it sounded any good would be another matter! But the idea of having everything in one box could help that a lot - I only ever use the PC as a source these days, and the Xbox also supports USB, so it'd be ideal for my needs. If I stuck with TI(the TAS5261 power-amp looks very interesting from a DIY point of view(mono chipamp, 125W at 8ohms with <0.09% THD), the TAS5518 PWM Processor looks devilishly complete and great for upgrading to more channels in future, but rather complicated, but the TAS5012 looks far simpler and would be a good starting point) - everything could be built up on individual boards during testing, and switched to a bespoke PCB once I'd sussed what I was doing. With everything being digital, even I should struggle to harm the sound much... 😉
http://focus.ti.com/docs/prod/folders/print/tas5261.html
http://focus.ti.com/docs/prod/folders/print/tas5518.html
http://focus.ti.com/docs/prod/folders/print/tas5012.html
Seems like a massive task, but it really is quite appealing - avoid the colouration of any opamps in the source, or degradation in sound quality by resampling the sound to a different bitrate, or from interconnects. USB doesn't really suffer from jitter, from what I've read - so many of the big decisions are removed from the plan 🙂.
Of course, the TI chips may sound pants. Technically, they look very nice, but paper-performance doesn't always translate into the real world... 🙂
--Rich
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