|
Post by seans on Jan 27, 2006 14:03:39 GMT
Hi all,
Busy looking at my Chiarra & planning to replace caps (PSU & Chiarra)
there seems to be a wealth of info and knowledge on the item on the forum! any advice?
I was thinking of: PSU the 2200 & 100 UF - Silmic a good choice? (I assume size the same)
Chiarra C5&6 (470uf), I believe these could be replaced with Bipolar (CLR?) - any suggestions C4 & 24 (2.2uf), any suggestions.
Cheers S
|
|
Nigel
Been here a while!
Watching over Gotham City keeping us safe
Posts: 2,064
|
Post by Nigel on Jun 7, 2006 15:16:34 GMT
Any thoughts about cap replacement or upgrades to the Chiarra? There seems to be a lot of positive thoughts about beefing up the caps in the X-Cans so what about the Chiarra? Also, the Andante power supply. How can that be improved?
Best,
Nigel
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jun 7, 2006 19:29:28 GMT
is there a schemo for the Chiarra available ?
Kinda hard to say what is an improvement and what is just tossing parts at something without the details.
I do know more than one amp has been screwed up in the area of SQ by increasing power supply cap size (including some of my own screw ups) and that even vaporised rectifiers not unknown when they were not up to a prolonged dead short as the capacitor bank charged.
|
|
Nigel
Been here a while!
Watching over Gotham City keeping us safe
Posts: 2,064
|
Post by Nigel on Jun 7, 2006 19:36:28 GMT
|
|
Nigel
Been here a while!
Watching over Gotham City keeping us safe
Posts: 2,064
|
Post by Nigel on Jun 7, 2006 20:09:20 GMT
Hi,
I forgot to mention, I've removed the output capacitors & use the 2 x Burr Brown OPA 627 BP on Browndog adaptor.
|
|
|
Post by PinkFloyd on Jun 7, 2006 20:21:45 GMT
Hi, I forgot to mention, I've removed the output capacitors & use the 2 x Burr Brown OPA 627 BP on Browndog adaptor. How are you getting on with your Chiarra Nigel? Long time since I saw that puppuy up these neck of the woods (your one that is!) Ever hear from sewerguy? Remember he was claiming great results with the LM6172 in the Chiarra? Mike.
|
|
Nigel
Been here a while!
Watching over Gotham City keeping us safe
Posts: 2,064
|
Post by Nigel on Jun 7, 2006 21:39:54 GMT
Hi Mike,
No, never hear from him these days. If I use that op amp, wouldn't I have to replace the output caps? I remember good things were written about a certain Analog Devices chip but I seem to recall 14v being too much, from the Andante supply, to incorporate it.
Yes, the Chiarra is still used daily & in fine form.
Pure Class A from the UK - remember?
I wonder what happened to those guys? Wordsworth, Drum, John & his Jake etc. I like to think they became so satisfied with the musical qualities heard they gave up searching for something potentially better.
Best
Nigel
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jun 7, 2006 22:26:03 GMT
looking at the schemo now and have to say I like the simplicity of the ciruit and especially so the "proper" use of a feedback loop to set bandwidth. The LF353 "engine" is fine being a way under rated part because of the rush to high current output ultra-high speed opamps even when not needed has blinded folks to other options. look at that internal schemo,sweet ! cache.national.com/ds/LF/LF353.pdfThe 8V/uS may seem low on paper but in reality is fine for audio frequencies though something in the 12-25V/uS range more comforting. Options of course are the before mentioned OP627 but even better the OP637 if the gain of +20dB is not changed (really is a better sounding chip ),the OP275 is a natural "drop in" as is the OP285 (the Ad745 would be a natural but only available in a 14 Pin DIP package) maybe the AD843,the "ADI OP627". R1 is inline so needs to be the best you can get C4 if an electrolytic can be replaced with a WIMA FKP if there is room, C5.C6 could use an 0,1 uf bypass cap,NPO or stacked film ceramics are nice here R8,R8A scrapped toally (2R2 is not doing shit !) or maybe replacing with the of Jensen Transformer OLI load decouplers unless you want an extra layer of short circuit protection then I would use 22R 1W resistors in series with the OLI with the Caddok MK132-22.0 being about as good as it gets I see zero coupling caps so that is one area you don't need to worry about,a good thing considering the cost of a good capacitor.......... Thinking on what the power supply needs to be without knowing the details of the actual unit I would say concentrate on filtration not capacitor storage begin at the mains entry with one of those enclosed RFI filter modules,toss an 0.1uf 1KV ceramic acorss the Mains switch contacts,add a snubber to the power transformer secondary (before the recifiers) then maybe replace the rectifiers themselves with better devices,toss a 10 ohm/5W wire wound resistor between the trafos secondary and the first stage filter capacitor followed by 2200uf/10 ohm-10w resistor/2200uf/regulator/2200 uf bottom line is most areas left open for improving are of the "make it bullet proof" type more than "how can I make this amp sound better" even though not mutually exclusive mods-getting rid of out of band crap is always a plus
|
|
|
Post by PinkFloyd on Jun 7, 2006 22:54:06 GMT
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jun 7, 2006 23:25:37 GMT
what the hell is the "Pyrite in the amp" all about ? Brit version of magic rocks ? more on topic- so you no longer have the amp but did ? Obviously it is not the layout that is lacking so the sonics were not up to par ? I think on my side of the pond there is minimal exposure at best for UK based amps and especially so once you get past Musical fidelity or Creek (mostly because of The Audio advisor) not a whole lot of info out there from U.S. based headphone sites which combined with FOTM and Fanboyism makes it a real bitch to get hard information.Being mostly reasonable in price also chases many from my country because they want either ultra expensive "all show and no go" or for budget amps the "DIY for Profit" crew who's amps mostly are variations on a theme and nothing special.Amps which more often than not bring their own problems to the plate that no legitmate manufacturer could have (must be plug and play with no hidden gothchas) without being ripped apart in the audio press. Me not being filthy rich I can not buy and evaluate every single amp on the planet even if those amps rewasonably priced so have to go on faith for some on the merits or lack of and that means lttle information if any on some of the more reticent designs like the Chiarra. So if I could make a suggestion maybe you could do a UK amp SQ ranking with each in its original un-modified state and not optimised version then maybe a 1-5 scale for say 1-Sound 2-Price 3-Build quality 4-SQ vs Cost etc. would really be a big help to many,myself included,if you ever find the time that is
|
|
|
Post by kittenyberk on Jun 7, 2006 23:35:00 GMT
what the hell is the "Pyrite in the amp" all about ? Brit version of magic rocks ? I assumed a cheap shot at the rainbow foil being fools gold
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jun 8, 2006 1:21:05 GMT
how about "ranbow foil for poor people"........the gum wrapper .
|
|
|
Post by PinkFloyd on Jun 8, 2006 9:04:20 GMT
what the hell is the "Pyrite in the amp" all about ? Brit version of magic rocks ? That was round about the same time as the rainbow foil Rick, the Iron Pyrite was supposed to deflect negative waves from the amp (or something along those lines) it didn't cost me anything as I have a few lumps in my stash (I believe I even sent Nigel a lump IIRC) so I thought "may as well give it a go" at the time. It would probably have worked in a loudspeaker cabinet (help to break up the standing waves) but in the amp it had no effect other tham placebo IMO. Looked nice though and added weight to the amp. Correct. I will be getting another one when I move. Sonics were VERY up to par and I still consider the Chiarra as the Rolls Royce of UK DIY amps. So simple, so bullet proof and so fantastic sounding it gets a pink 10/10. I got sidetracked with the WNA (which if truth be told isn't a patch on the chiarra) and Shaun Williams (owner of Williams Hart) moved over to Spain and was out of touch for a while. Now he's back in the land of the living I will be ordering another chiarra / andante kit from him all ready to build in the new house. As I say, the Chiarra was my favourite UK DIY amp and I look forward to adding another one to my collection very soon as I really miss its lovely sound. Will do Rick! Again, it'll be after I move house as I'll have a lot more space for my thoughts and peace to get on with important things like amp reviews. Mike.
|
|
Nigel
Been here a while!
Watching over Gotham City keeping us safe
Posts: 2,064
|
Post by Nigel on Jun 8, 2006 9:26:29 GMT
Thank you for your replies. Phew!
Can't wait for you to get another, Mike. Then we can reap the benefits of your experiments/knowledge.
|
|
|
Post by PinkFloyd on Jun 8, 2006 10:25:35 GMT
Thank you for your replies. Phew! Yup, you certainly get only the best quality replies when Rick's in the house I'm thinking of renting him out on a purely "pay per reply" basis with 10% going to me, 10% to the upkeep of my website and 80% going in Rick's back pocket ;D Soon Nigel and you'll be the first to know. BTW do you know I'm moving way up North? I'll give you a ring and let you know my new contact details etc. Mike.
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jun 8, 2006 14:03:55 GMT
Just read the "Rock grotto" Chiarra amp pages,always a good idea before spouting off (too late ! too late ! All is LOST !),and it seems the on board chip has limitations in SQ I don't remember from past use (eighties ? Early nineties ? was the original PAS-4 AVA mod chip) and will take Mikesters word for the results because he listens to gear. Anyway,seems this amp is a real sleeper that is only missing exposure for it to be mentioned in the same sentence with other contenders in the Kit arena though being a mostly foolproof design,not much you can screw up even if you tried short of slamming in a 741 opamp ( ) not a whole lot bad a person could do even by intent ;D The OPA627 observation is one that is/has been known for some time.With Senns is THE chip of choice because for some reason it mates ying/yang with the sonic signature of those cans but being a Grado man I find I prefer more bottom end slam that the BB chips offer so mostly go to the ADI library for my monolithics.There really is a house sound for both. So I guess the original question of "how do i improve on this amp" comes down to the normal Pink floyd/Mad Mike panny cap mods retaining the same values along with improved RFI protection on all inputs and outputs plus maybe an opamp replacement. painless mods all Oh yeah : Mike,i need to give you some lessons on "Amps as Art" because that has to be about the fugliest quality amp i have even seen in my entire life ! What were you thinking man !
|
|
|
Post by PinkFloyd on Jun 8, 2006 19:23:16 GMT
This one? That's the stock "corned beef tin" that Williams Hart supplied with the kit, you want to see it "before" it was painted (ouch!) The previous owner of Williams Hart (Tony Hart) used to supply a much nicer pre punched screen printed enclosure but when Shaun Williams took over he pared things down to the bone and that included the enclosure..... bang went the good quality one and in came the cheap as chips £5 corned beef tin you see above. Actually, Nigel has these corned beef tins and "likes" the appearance of them..... IIRC he classed them as very "80's hairshirt" so there!
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jun 8, 2006 20:31:11 GMT
Shadow type covers on;y work when the panel color is the same or lighter so for a real "retro" look it needs to go to satin black cover with a silver or gold hammertone chassis.Hammertone paint does not hold up well unless you bake it in a toaster oven or use heat lamps at 10 inches or so for a couple of hours.To stay in total character you would then use either a bone or brown colored NOS plastic knob,possibly with a dial plate with tick marks denoting postition SOOOOOOO THERE WISE GUY !!!!!!!
|
|
|
Post by PinkFloyd on Jun 8, 2006 21:04:06 GMT
That sounds bloody awful Rick, typically "American" I'm surprised you didn't add a chicken head knob into the mix just to really over emphasise the cheapness of the enclosure Gold hammertone chassis?? that sounds soooooo "gracelands", soooo fried banana sandwich, soooooo gauche, soooo Liberace............
Grey and black is minimalist and not pretentious, it's what inside the box that counts!
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jun 8, 2006 21:27:52 GMT
Obviously your education is severly lacking or you would have heard of these guys MANY hammertone chassis amplifiers Then there are the classic Marantz Tube amps,more bronze hammertone than gold but still "Hammer time" would have if there was a front panel rotary switch involved which is the Chicken Head Domain being the best knob ever invented for easy switching but since it is only a cheesy pot I figured a nice NOS ivory knob with some patina would be best.. You really do need to get out more wise guy
|
|
|
Post by PinkFloyd on Jun 8, 2006 21:47:41 GMT
Don't tell me about "hammer time" I know all about it! More hammers than you can shake a stick at! See? I do get out and about....
|
|
|
Post by PinkFloyd on Jun 8, 2006 21:51:02 GMT
Obviously your education is severly lacking or you would have heard of these guys Yes, they were in vogue when uri gagarin was up in space and The beatles were at number one in the charts
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jun 8, 2006 22:07:31 GMT
....................and will still beat the shit out of much that passes for high end audio these days
|
|
|
Post by PinkFloyd on Jun 8, 2006 22:09:08 GMT
On the subject of the World famous British company LEAK, I've got an old troughline tuner in the eves which will be getting some airtime when I move, was just up in the attic removing the FM aerial and thought about the troughline. hope it still works :-)
I've also got "one" broken LEAK sandwich speaker in the garage but it's a LEAK / "rank" one so will probably be a dustbin job.
|
|
rickcr42
Fully Modded
Rest in peace my good friend.
Posts: 4,514
|
Post by rickcr42 on Jun 8, 2006 22:11:37 GMT
LEAK Point One TL/12 Tube Amplifier.
This much sought-after amplifier, became justly famous, as the first to offer point one (0.1%) harmonic distortion;all the more remarkable, when it is remembered that this was back in 1949.The amplifier uses KT66 tubes(triode connected) for a power output of 12 watts.Input sensitivity 160mV,output impedance 2,7-9,15-20 and 28-36 ohms.Frequency response 20Hz to 20kHz,signal to noise level 80dB at 10 watts.Feedback 26dB.The manufacturers,H.J.Leak & Company of London, sold 731 TL/12 amplifiers to broadcasting authorities around the world in 1950,including the BBC,the South African B.C.,the Swiss B.C. and the Italian B.C.etc.It is a measure of the high quality of the amplifier and the respect accorded to it, that over half a century ago (1949), the price was in excess of $100 U.S.Dollars.looks like the ultimate Grado driver (look at the trafos specs) ;D and exactly which beatles song was that playing in 1949 ?
|
|