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Post by Deleted on Nov 25, 2011 14:22:47 GMT
This'll be fun! What sort of sinkage do you need? Hi Jon I'm going to use the 300 U4 2000 that's applied for a change of job  I'm hoping that's going to be enough. also the PSU is going to need some heat help so i was going to order the U2 version for that side of things. just on heat sinks Alex i noticed that you have your 327/337 sinked. i did read that this would be necessary in the original article but any tips (what to use) would be good. take care |
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Will
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Post by Will on Nov 25, 2011 18:53:12 GMT
The Class A article says that to-18 sinks will fit the 327/337, with a bit of persuasion. Ebay has these and these, so we should be OK on that front. On the case front, the same article suggests the altronics h0545 heatsink, which appears to be 2U high. Thinking about 3U modushop unit myself, and a normal case for the PSU (two psu's sinking c1A-ish each) |
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Will
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Post by Will on Nov 25, 2011 19:05:49 GMT
Quote: I know, but it just seems strange after all that's been done and said when it comes to PSU quality and audio! Chris We need to remember here that most modern SS amplifiers also have a very high PSRR, (Power Supply Rejection Ratio) and the front end and VAS stage (Voltage Amplification Stage) are the most susceptible areas.We have covered those areas. People are of course free to experiment in that area, and try non CL JLHs feeding the complete amplifier modules. However, I wouldn't do that unless using those beefier LT devices for the voltage regulators. Alex P.S. I would recommend using 2 x 2,200uF 10V low ESR in parallel , not 2 x 4,700uF, in the CL version of the JLH. Hi Jeff (  ) Thanks for posting the updated circuit, I was doing an update to send to you for the OK (updating the LTP mod bits an' that). Might be worth clarifying that the output devices shown in the circuit diagram are interchangeable with several other devices, depending on what's available locally. The ones in the diagram, 2sa1943/2sc5200 and mjl1302/mjl3281 are all good (thanks to Alex for the info) The latter are available over the counter in Altronics, and I've found a good supply of them for £1.60 per device, which is not bad. I think doing a GB for the output devices might be a good idea for us guys here in UK/Europe. |
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Post by Deleted on Nov 25, 2011 19:15:59 GMT
The Class A article says that to-18 sinks will fit the 327/337, with a bit of persuasion. Ebay has these and these, so we should be OK on that front. On the case front, the same article suggests the altronics h0545 heatsink, which appears to be 2U high. Thinking about 3U modushop unit myself, and a normal case for the PSU (two psu's sinking c1A-ish each) Hi Will thanks for the heat sink info. I've just started to re-read the SC article so I've not got to that part yet. I've ordered ten of those spikey job heat sinks so if any one needs a pair let me know. one thing that i was curious about was if the various available OP devices have any sound differences. i know there has been quite a discussion on the subject for the F5. just curious. take care |
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Will
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Post by Will on Nov 25, 2011 19:35:06 GMT
Hi Shaun,
Me too!
I think we can sort out 3 other amp builders between us, with the spares.
Once I've got the pcb sorted, I'll post a bom, probably an online excel spreadsheet with links (so that everyone can read it). Having said that, a lot of the components are the same, so we should be OK on that.
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Post by Deleted on Nov 25, 2011 22:39:31 GMT
Hi Shaun, Me too! I think we can sort out 3 other amp builders between us, with the spares. Once I've got the pcb sorted, I'll post a bom, probably an online excel spreadsheet with links (so that everyone can read it). Having said that, a lot of the components are the same, so we should be OK on that. Hi Will sounds like a plan to me  yes i breathed a sigh of relief when i clapped eyes on the old friend that that circuit has become. i have most things from the last build which makes things a little easier. transformers to order Monday and i think I'll go with Airlink who I've had great service from in the past. I'll add the bells and whistles to the basic TX and expect to receive them in time for the big birthday surprise. take care |
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Post by jeffc on Nov 26, 2011 2:09:09 GMT
Yer I picked that up too Will, he is getting on in years, don't be too harsh. With the number of PMs I've been hitting him with over the past week or so to help sort out a voltage stability issue with my SC-DAC, I'm not surprised he's frazzled cheers.. jeffc |
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Post by Deleted on Nov 26, 2011 3:02:16 GMT
Jeff And you aren't frazzled ?  Alex P.S. A hint to others . Turn off the Auto scan facility. |
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Post by jeffc on Nov 26, 2011 5:27:55 GMT
yer only x 1,000-fold at the peak  and so glad its all back together in one piece at last |
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Will
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Post by Will on Nov 26, 2011 9:18:31 GMT
Yer I picked that up too Will, he is getting on in years, don't be too harsh. With the number of PMs I've been hitting him with over the past week or so to help sort out a voltage stability issue with my SC-DAC, I'm not surprised he's frazzled cheers.. jeffc Hi Jeff, I'm sure Alex knew I was kidding about. Like most people ( I hope  ), I get names mixed up, calling the dog the wife's name, mixing the boys up and sometimes knowing who I'm talking too, but wondering what their name is! As for helping people out, I get the impression that Alex 'clocks on' each morning to a whole long email list of 'help!' in various guises, but still manages to make each person feel like they have his undivided attention. Top Man  |
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Post by Deleted on Nov 26, 2011 11:18:52 GMT
yer only x 1,000-fold at the peak and so glad its all back together in one piece at last Hi Jeff great news  ''Turn off the Auto scan facility'' is that a new tweak? ;D ;D ;D ;D take care |
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Post by Deleted on Nov 26, 2011 17:55:31 GMT
hi all well i hit the button on my birthday transformers and ended up going for: www.airlinktransformers.com/chassis_mounting_toroidal_transformers_standard_range/3-CM0160220.htmlso 2 x 230 20-0-20 @160va with the double screen which look good and up to the job. there was only £1 difference in price between the 120VA and the 160VA so i went for more beef. i have 2 x 230 22-0-22 180VA in the Audiosector if needed but as i said 15W is plenty enough for me and no need to think about that extra couple of volts it's just more heat. it's a good encouragement to build something with my Fostex167E full range drivers (OB'S have become tooo big for the space i have). I'll post some pictures when the transformers arrive arrive. take care |
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Post by jonclancy on Nov 27, 2011 2:18:43 GMT
On the case front, the same article suggests the altronics h0545 heatsink, which appears to be 2U high. Thinking about 3U modushop unit myself, and a normal case for the PSU (two psu's sinking c1A-ish each) Thanks Shaun and Will. I'll have a look around and see what the Barrred Boss on eBay has in stock: Barrred Boss - that's 3 RsPrices look a bit high nowadays.  Maybe Altronics is an option... |
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Post by pagan on Nov 27, 2011 4:01:54 GMT
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Post by Deleted on Nov 27, 2011 4:28:40 GMT
BTW, if you want to know whether it is worth all the time and expense, ask Allan in a PM, as he is one of the several Sydney members who have heard mine, and he ALSO owns the SC 20W Class A .Allan might even recommend going with the complete Altronics 20W kit instead,which Jeff said has been reduced to $499.
Alex
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Will
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Post by Will on Nov 27, 2011 9:58:23 GMT
Might it be better if Allan posted his thoughts here?
That way everyone is is interested in building the amp can make an informed decision on which way to go. I take it the 20W amp pcb is easy enough to modify for the front end LTP mod?
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Post by Deleted on Nov 27, 2011 10:43:47 GMT
BTW, if you want to know whether it is worth all the time and expense, ask Allan in a PM, as he is one of the several Sydney members who have heard mine, and he ALSO owns the SC 20W Class A .Allan might even recommend going with the complete Altronics 20W kit instead,which Jeff said has been reduced to $499. Alex Hi Alex all i need to do is have a listen to your Class A HA/PRE and if the 15W has half of what that has then it's going to be well worth it. in most cases building a DIY amp blind or anything else for that matter has to involve some faith in the abilities of the designer. not to many around here to get a listen to but your Class A ha/pre is just superb so I'll go on that. yes it's relatively expensive but in terms commercial cost it's very reasonable for what's on offer. if parts are accumulated over time then they don't bit tooo much. so for my birthday I'm getting something useful and not another pair of socks. for Xmas the same as my family know me well enough to just ask what audio stuff i would like which is cool. so I'll build on the basis that if i find that it's not what i want then I'll still have learned plenty about building this sort of amp. that's partly what DIY is about IMHO. so no worries on that. that circuit with your LTP balancing mods is proved to work well. take care |
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Post by Deleted on Nov 27, 2011 10:51:38 GMT
No. |
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Post by jeffc on Nov 27, 2011 11:38:17 GMT
I'm thinking I might have to wave another flag for downunder and give Phil some company . As with the AK Class A HA, a speaker amp version of this is too much of a once-off opportunity to miss out on. Plus Phil and I might be able to share in local parts costs and save a few $ like with these www.altronics.com.au/index.asp?area=item&id=H0545Plus...... It might just get Alex off my case about quite liking the sound of my Class D Audio kit amp. cheers.. jeffc |
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Post by Deleted on Nov 27, 2011 11:51:27 GMT
Class D ? Chuck, chunder !  Those U beaut DIY panel speakers are wasted on that ! ;D Your Class A HA can also do double duty as a preamp. |
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Post by Deleted on Nov 27, 2011 13:55:53 GMT
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Will
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Post by Will on Nov 27, 2011 20:07:02 GMT
I'm thinking I might have to wave another flag for downunder and give Phil some company . As with the AK Class A HA, a speaker amp version of this is too much of a once-off opportunity to miss out on. Plus Phil and I might be able to share in local parts costs and save a few $ like with these www.altronics.com.au/index.asp?area=item&id=H0545Plus...... It might just get Alex off my case about quite liking the sound of my Class D Audio kit amp. cheers.. jeffc Good Man! I must admit, you guys in Australia are spoilt for choice when it comes to electronics stores. Being able to walk into a store and buy quality heatsinks like that is amazing, and at a good price as well. And having conrad local is also a boon. |
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Will
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Post by Will on Nov 27, 2011 20:15:14 GMT
Hi Alan, I've heard good things about them, so worth while checking prices. Last time I checked with them (a year) though, the guy that Jon linked to, and shipping in from Conrad in Australia were the cheaper options. |
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Post by Deleted on Nov 27, 2011 21:21:00 GMT
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Post by jeffc on Nov 28, 2011 5:51:01 GMT
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I'm hoping that's going to be enough.
)
and so glad its all back together in one piece at last 
), I get names mixed up, calling the dog the wife's name, mixing the boys up and sometimes knowing who I'm talking too, but wondering what their name is!
Maybe Altronics is an option...
