leo
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Post by leo on Jul 2, 2007 11:59:32 GMT
Thought I'd stick the Chiarra turned Heed into a new thread instead of clogging Mikes WTF thread up with it:) I'll post a piccy later but here is the standard modded Chiarra schematic and the second one is what I've changed. It was basically the easiest way for me to try the Heed circuit, only thing I have not done yet is the 100uf/ 100R for the supply line, I just swapped the 470uf caps to 100uf. Supply is currently a modified pair of super regs supplying +/-12v's, I also only had 150R 7w resistors where the 100R 5w should go on the BD139's emitter to -12v I use axial 10uf tants for the caps in the feedback loop, I'm going to try some solid aluminum types next, its worth using good quality here
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leo
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Post by leo on Jul 2, 2007 12:50:29 GMT
Does anybody have the schematic for the Chiarra's psu? I've not had one because I ran mine from something else. It should be easy to adjust the Andante to suit the Heed. The Heed uses a transformer with dual 9v AC secondarys wired up as centre tapped, this would give just over +/-12v DC supply, you can just change the regulators in the Andante from 15v to 12v (i presume it uses fixed not adjustable LM317/337 types) Regarding the connections if we can find the schematic we can see whats going off in there. If you want to try a regulated supply with the Heed the easiest way just to try it is to remove the 10,000uf caps and rectifier diodes, just feed the regulated +/-12v and ground supply to where the 10,000uf caps was
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leo
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Post by leo on Jul 2, 2007 13:42:51 GMT
Ok heres a piccy, sorry its not very clear, my camera is crap. Anybody know why the Heed circuit sounds better than the Chiarra? is it the type of feedback or the zobel on the output of the Chiarra? Any idea's what else I could try? I can post the results.
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leo
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Post by leo on Jul 2, 2007 13:49:43 GMT
The 100nf cap going from pin4 to 8 of the op-amp is soldered underneath, I also had to place one of the original links underneath the pcb because the BD139 is a different pinout to the original transistors used in the Chiarra so the the 139 and its heatsink had to be reversed, the pcb print is still original, no other wires etc added to the bottom One of those axial tants had to be reversed because of the track underneath
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Nigel
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Post by Nigel on Jul 2, 2007 20:22:15 GMT
So basically Leo, the Heed circuit isn't too different from the Chiarra?
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leo
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Post by leo on Jul 2, 2007 21:07:35 GMT
Not really, theres more bits in the Chiara but I find the Heed circuit still sounds better. The Heed has a wider soundstage, more details, less warmth/coloration to my ears, both amps drive my phones well loud enough for my needs.
The track layout of both amps is very similar so it was easy doing the conversion, It also allows me to experiment quite easy.
I've now tried a raw DC supply of +/-12v using a 9v transformer, Hexfred rectifier diodes and a pair of 10'000uf Rubycon caps. IMHO the super regged version is much bette rbut saying that these are better than the standard 7812/7912 type regs, If I have any standard regs I'll compare those against the raw supply to make it more fair. With the super regs I found the sound just more effortless
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Post by PinkFloyd on Jul 2, 2007 21:21:22 GMT
Yes. I'll have to take a pic of it as I threw my scanner in the bin Let me go find it, it's here somewhere.
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Post by PinkFloyd on Jul 2, 2007 21:39:34 GMT
Sorry leo but in typical Shaun Williams style the schematic he supplied with the kit is totally illegible... no scanner will make sense of it... I took a pic (with my crap camera) hopefully you can get something out of it. I have no use for the original so will send it to you along with the caps I promised (still haven't got round to packing them have been busy but will do so tomorrow) you really will have a hard time making things out.... it's not clear. Here's a photo anyways:
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leo
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Post by leo on Jul 2, 2007 21:50:14 GMT
Cheers Mike, thats acually a help, it looks to be totally standard anyway, Nigel mentioned the Andante had more than three pins for the output so I wanted to see whats going off in there. Hey no rush at all with those caps mate, with the postal strikes etc just send them whenever its convenient for you
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leo
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Post by leo on Jul 2, 2007 21:59:27 GMT
Looks like the Andante can be done to supply more than just the Chiarra, Nigel could just keep the existing 15v regs and just add some 12v ones with some nice decoupling caps too, I presume the pcb has unpopulated track ready to accept more regs giving him multiple output regulation
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Post by PinkFloyd on Jul 2, 2007 22:00:13 GMT
Maybe just a case of less is more leo, the Chiarra was bullet proof in every department (it had to be being a DIY kit) you've just stripped some of the kevlar coating out....... you've lost the belt and braces I just hope your trousers don't fall down unexpectedly While you were at it you could have removed those LED's from the circuit if it's a true Heed those resistors will be running finger burning hot.... are they?
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Post by PinkFloyd on Jul 2, 2007 22:02:55 GMT
+15V / 0V / -15V
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leo
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Post by leo on Jul 2, 2007 22:11:51 GMT
Maybe just a case of less is more leo, the Chiarra was bullet proof in every department (it had to be being a DIY kit) you've just stripped some of the kevlar coating out....... you've lost the belt and braces I just hope your trousers don't fall down unexpectedly While you were at it you could have removed those LED's from the circuit if it's a true Heed those resistors will be running finger burning hot.... are they? Nicely put Yes the resistors do get hot, its going to be less current with 150Rs I fitted than the original 100R value though, next time I pop into Maplins I'll pick a couple of 100R's up I've been leaving the amp on running quite hard into loading resistors just to keep an eye on it, I can't imagine ever running it this hard with my headphones, I'd be deaf after a day Anyway so far the sound is quite good, just thinking where to go from here
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Post by PinkFloyd on Jul 2, 2007 22:14:48 GMT
I have a couple of the sprague koolohms left, you want them?
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leo
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Post by leo on Jul 2, 2007 22:26:48 GMT
Owt else ;D You've got more stock than Farnell Anyway don't bother with resistors Mike, I've got to go to Maplins anyway because I need some sockets but thank you anyway. What amp you listening to lately Mike?
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Post by PinkFloyd on Jul 2, 2007 22:36:01 GMT
Go listen to some music man or go outside and sniff the roses, get some fresh air, I'm resting on the back burner for a while and it's good it clears the cobwebs out of your head... way too much time spent with a soldering iron in my hand and not enough time spent sniffing the roses.
I'm actually listening and getting into the music now, quite happy with it.... spending ages on something just to get a nth of subtle improvement is time wasted.... if the bass isn't quite right pour yourself a pint of whisky, if the mids aren't airy enough smoke a joint or two.... you'll soon realise the most important thing to tweak is yourself.... if you aren't conditioned to receive then no amount of cap rolls will make things better.
Instead of spending ages tweaking the system have a go at tweaking yourself... once you find the right tweak for yourself you'll really zone in bigtime on the meaning of the music......
I'm off to zone in to Buddy Rich "Tuff dude" got my pipe fired up all ready to enter the Jazzclub..... oh yeah baby!
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leo
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Post by leo on Jul 2, 2007 22:59:38 GMT
Now thats the advice I like Was just listening to Pro's and cons of Hitch hiking before posting. Hey that Oceania from The songs of a distant Earth is about the best I've heard it through the headphones using this amp, quite enjoyable
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leo
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Post by leo on Jul 2, 2007 23:08:38 GMT
I was actually thinking of getting some better headphones now, these HD540 references look older than I am
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Post by PinkFloyd on Jul 2, 2007 23:11:23 GMT
At this very moment in time listening to Buddy through the Ergo model... 2 headphones powered by Ergo Amp 1.
My usual companion is a dogeared MF v2. The old headcase HFN009 gets the occasional airing and the Graham Slee Solo is permanently connected to my telly. The WNA MKlll just sits in a cabinet (as does the B-Tech 928, X-Cans, X-Can v3, Creek OBH-11, Gmoy, Cmoy, Mint blah blah blah) way too many small amps gathering dust.
You may have gathered from my recent posts that I'm not as passionate as I once was...... correct.....I've had so many damned headphone amps in my possession (be they my own or others passing through) I've lost count.... the one thing I have noticed is there isn't a shedload of difference between all of them (well, most of them) much of a muchness with only subtle differences really standing out to the trained ear.
I just can't enthuse anymore and think I've reached the conclusion that it's not the amp that doesn't sound good it's the person listening to it who has lost the plot.... hell, a £1 radio playing the right song can get us tapping our toes yet we sit like statues analysing everything the older we get getting nothing out of anything...... trust me, I've been auditioning equipment for many years but I have only just started to evaluate myself......
The equipment means feck all when it comes down to musical enjoyment.... look at yourself as a high end receiver..... you get a bad signal you'll blame the equipment..... the guy next door with his el crappo radio will be dancing, singing "and" shagging his wife in time to the music....."audiophiles" are nothing more than people who have forgotten how to enjoy the music.
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leo
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Post by leo on Jul 2, 2007 23:43:47 GMT
Yes, the music is the important thing but its nice to have the good sound quality too:) I've been into Hi-fi for a while but quite new to headphones compared to the guys on here. Already I'm enjoying things more with the Heed clone, using say the Millet after a couple of songs I'd switch it off and stick the main hi-fi on instead, the music just made more sense.
Anyway I can finally enjoy late night music without disturbing folks in bed ;D The little Cmoy is still fun and will be used to do the old op-amp and cap rolling if needed
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