Spirit
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Post by Spirit on Mar 27, 2009 5:32:59 GMT
If you're getting the JLHs from Jon (jonclancy) as per rockgrotto.proboards.com/index.cgi?board=786345&action=display&thread=2943&page=14- you'll need both a +ve and -ve board.Hi guys, This is for those of you who may be considering building the Silicon Chip Headphone Amplifier, and modifying it to 'AK' status. I've listed just about all the components you'll need, and where to get them if you're in Australia. It's entirely possible there are better ways to get them (ie where my suggestions only come in packs of 10 and you only need 1), but this is just intended as a getting started quickly guide. The JLH (power supply filter) components are for the non-current-limited (for use in the SCHA) version. Also, credit to Alex (sandyk) for most of the 'extras' list at the bottom Cheers, Phil [Rob mentioned below is robertkd on here.] Excel document: www.fractalist.net/scha/JLHv2-Parts.xls
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Post by jphoward on Mar 27, 2009 6:02:18 GMT
I was just in the middle of a similar document, so I'll post it here instead. Here's a list of stuff you can get from Jaycar (I've skipped those where Spirit has already provided the Jaycar part number); using Jaycar you can get everything from one place, except for Toshiba trannies (WES, as per Spirit's list), and the LM4562 (see below). - BC549C (to replace BC550C): ZT2156
- BC559C (to replace BC560C): ZT2168
- BD639: ZT2179
- BD640: ZT2180
- 1uF electrolytic: RE6032
- 33R: RR0536
- 1K: RR0572
- 2K2: RR0580
- 2K7: RR0582
- 10K: RR0592
- 100K: RR0620
- 120K: RR0622
- 4R7: RR1518 (5% / 0.25W)
- 470pF ceramic:
RC5332 Update: Jaycar doesn't seem to have a suitable part - see sandyk's post below
Note that these resistors (except for 4R7) are 0.5W. I also suggest getting 'Hook-up wire pack' WH-3025 if you don't have a good supply of hook-up wire. Note that there's not enough 0R0 'resistors' in the kit, but if you simply snip the legs off any resistors lying around, they will do very nicely. You can buy the LM4562 from Better Computers - they have stock, and online orders are shipped quickly (or at least, mine were).
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Post by jphoward on Mar 27, 2009 6:13:23 GMT
I should mention, I haven't tried this particular part myself - I'm not sure if it's OK to use ceramic for this "diode switching noise" capacitor.
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Post by Deleted on Mar 27, 2009 6:37:07 GMT
I should mention, I haven't tried this particular part myself - I'm not sure if it's OK to use ceramic for this "diode switching noise" capacitor. Jeremy No, it isn't suitable. The voltage rating needs to be at least 100V. I used Rockby Electronics (Victoria) Stock No: 34463 > Part No: C056T471K2X5CP7301 > Description: 470pF 200V MKT Capacitor > Pricing > 10 up: $0.300 > > Value: 470pF > Volts: 200VDC > Size: 5 x 5 x 2 > Spacing: 5mm > Type. KEMET > Qty On Hand : 947 The MF resistors are best bought from Jaycar in packs of 8. I recommend 4 x 2.7K resistors, to permit the small modification to the JLH PCB as well. DSE stores are unlikely to have these components over the counter any more. All Jaycar owned stores will have them in stock. Alex
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pagan
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Post by pagan on Mar 27, 2009 11:04:43 GMT
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robertkd
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Post by robertkd on Mar 27, 2009 11:37:11 GMT
[quote author=jphoward You can buy the LM4562 from . Ouch there expensive,..
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Post by nickyboyo on Mar 27, 2009 12:09:01 GMT
Rob, i have looked through the majority of your posts with regards to the tweaks to the scha amp, and all i have seen are circuit diagrams- great for somebody of an electrical disposition, but not much chop to a layman. Do you have any similar layout diagrams and component lists, like Alex has done for his version? What are the differences between both of your approaches, and has a comparison ever been tried out? I would love a listen in to both your units side by side sometime
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pagan
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Post by pagan on Mar 27, 2009 12:38:36 GMT
[quote author=jphoward You can buy the LM4562 from . Ouch there expensive,.. Yes they are Might be cheaper from farnell or RScomponents now thats just funny,.... cheaper
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Post by wink on Mar 31, 2009 13:04:15 GMT
The 2SC5171's I bought from WES were a mixture of genuine Toshiba and the ones with the T in the circle. I checked them with a transistor checker. The difference is that the originals have about twice the Hfe of the others. I have tried before to exchange transistors with WES, but their policy is no exchange. Out of 10 of them I had 4 cheapies.
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Post by jphoward on Mar 31, 2009 14:23:59 GMT
I also had a problem with receiving some crappy trannies for WES this week (for a different project) - very annoying. However they seem to a better selection of transistors than anyone else in Aus I'm aware of. Does anyone have suggestions for alternative suppliers?
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Post by Deleted on Mar 31, 2009 20:17:18 GMT
I also had a problem with receiving some crappy trannies for WES this week (for a different project) - very annoying. However they seem to a better selection of transistors than anyone else in Aus I'm aware of. Does anyone have suggestions for alternative suppliers? Jeremy Have you checked RS and Farnell ? Digikey and Mouser are very good , but their P&P can be a killer for small orders. Ampslab is also quite good for some of the devices, and service is excellent. Alex
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Post by Deleted on Mar 31, 2009 20:28:15 GMT
The 2SC5171's I bought from WES were a mixture of genuine Toshiba and the ones with the T in the circle. I checked them with a transistor checker. The difference is that the originals have about twice the Hfe of the others. I have tried before to exchange transistors with WES, but their policy is no exchange. Out of 10 of them I had 4 cheapies. The majority of mine have come from : audiolabga.com/mal_cart/mal_cart.php?find=2SC5171&gclid=CJWMmvb_zZkCFRMaewodZygyswP.S. The vast majority of mine have measured HFE between 170 and 210, and I have never had one with HFE less than 150
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Post by jphoward on Mar 31, 2009 23:06:49 GMT
Have you checked RS and Farnell ? Digikey and Mouser are very good , but their P&P can be a killer for small orders. Ampslab is also quite good for some of the devices, and service is excellent. Not much luck from RS or Farnell (Farnell had nothing I was looking for, RS had 2 of 3 listed, but one was out of stock, the other was 'extended range' 6-8 days from the US). I'll check out the others you mentioned. I've been trying to order from Aussie suppliers who have stock, since I'm not very good at being patient...
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Post by elliot42 on Apr 8, 2009 11:00:40 GMT
I've seen that it's possible to use different transistors in the SCHA other than the suggested replacements 2SC5171 and 2SA1930 such as 2SD669A and 2SB649A or 2SA1837 and 2SC4793. Is it also possible to use one of these other combinations in the JLH? I ask because WES are out of stock of the 2SC5171 at the moment but they have all the others in stock.
Or am I better off waiting a little and get the 2SC5171 and 2SA1930 for both the JLH and SCHA?
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robertkd
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Post by robertkd on Apr 8, 2009 11:50:54 GMT
I've seen that it's possible to use different transistors in the SCHA other than the suggested replacements 2SC5171 and 2SA1930 such as 2SD669A and 2SB649A or 2SA1837 and 2SC4793. Is it also possible to use one of these other combinations in the JLH? I ask because WES are out of stock of the 2SC5171 at the moment but they have all the others in stock. Or am I better off waiting a little and get the 2SC5171 and 2SA1930 for both the JLH and SCHA? I am currently exploring an SC HA with 2SD669/2SB649 and initial findings are very impressive, although early days still tweaking bias and emitter resistor values
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Post by Deleted on Apr 8, 2009 11:56:30 GMT
I've seen that it's possible to use different transistors in the SCHA other than the suggested replacements 2SC5171 and 2SA1930 such as 2SD669A and 2SB649A or 2SA1837 and 2SC4793. Is it also possible to use one of these other combinations in the JLH? I ask because WES are out of stock of the 2SC5171 at the moment but they have all the others in stock. Or am I better off waiting a little and get the 2SC5171 and 2SA1930 for both the JLH and SCHA? Elliot As the 2SA1930 is still in stock, I would use it, and the 2SC4793 Alex
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Post by elliot42 on Apr 8, 2009 13:10:19 GMT
And those two would be fine to use for the JLH as well as the SCHA?
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Post by Deleted on Apr 8, 2009 13:25:34 GMT
And those two would be fine to use for the JLH as well as the SCHA? Elliot YES. Alex
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Post by elliot42 on Apr 8, 2009 13:36:55 GMT
OK. Got it Just making sure. I'll get an order placed then.
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Post by Deleted on May 24, 2009 22:19:09 GMT
FAKE TOSHIBA DEVICES. This morning I received the following from a friend in Sydney:
"I have recently had a bit of time to ponder why this ripple eater was not impressing me as much as your's did. Yes, I fell for the oldest trick for young players, these bastards at WES gave me fake 2SC5171s, not the official T of Toshiba but a T in a circle, hfe 85-100 compared to 230 from the Toshiba and I'm betting if I had the boys toys to test for Ft it would be nowhere near 200mhz, the bastards. So all I had in the cupboard were some Sanyo 2SA1538/2SC3953 TO126, 400mhz, hfe112 Cob a bit better, but what a difference a couple of weeks of f'ing around makes, good line for a song. I am now happy with the result and will now start cloning some more."
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FritzS
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Post by FritzS on May 25, 2009 8:05:24 GMT
FAKE TOSHIBA DEVICES.This morning I received the following from a friend in Sydney: "I have recently had a bit of time to ponder why this ripple eater was not impressing me as much as your's did. Yes, I fell for the oldest trick for young players, these bastards at WES gave me fake 2SC5171s, not the official T of Toshiba but a T in a circle, hfe 85-100 compared to 230 from the Toshiba and I'm betting if I had the boys toys to test for Ft it would be nowhere near 200mhz, the bastards. So all I had in the cupboard were some Sanyo 2SA1538/2SC3953 TO126, 400mhz, hfe112 Cob a bit better, but what a difference a couple of weeks of f'ing around makes, good line for a song. I am now happy with the result and will now start cloning some more." Alex, are the Sanyo's the better choice? for JLH and 15W Class A HA too?
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Post by Deleted on May 25, 2009 8:22:17 GMT
FAKE TOSHIBA DEVICES.This morning I received the following from a friend in Sydney: "I have recently had a bit of time to ponder why this ripple eater was not impressing me as much as your's did. Yes, I fell for the oldest trick for young players, these bastards at WES gave me fake 2SC5171s, not the official T of Toshiba but a T in a circle, hfe 85-100 compared to 230 from the Toshiba and I'm betting if I had the boys toys to test for Ft it would be nowhere near 200mhz, the bastards. So all I had in the cupboard were some Sanyo 2SA1538/2SC3953 TO126, 400mhz, hfe112 Cob a bit better, but what a difference a couple of weeks of f'ing around makes, good line for a song. I am now happy with the result and will now start cloning some more." Alex, are the Sanyo's the better choice? for JLH and 15W Class A HA too? Friedrich IMHO, no. Their HFE varies much more, and they have a lower maximum collector current and power dissipation. Alfred only used them because he had stocks of them. Nearly all the 2SA1930 and 2SC5171 that I have tested, have HFE between 170 and 210, so better matched pairs are readily obtainable. Alex
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Post by elliot42 on May 26, 2009 12:58:49 GMT
I bought some transistors from WES a few weeks ago and the ones I got are all genuine Toshibas. I guess it could be a bit of a lucky draw depending on what they currently have in stock? I measured the hfe of each of them (with my pretty old, cheap DSE DMM, don't know how accurate it is): 2sa1930 - 171, 174, 184, 191 2sc5171 - 160, 171, 174, 175 Those seem a bit on the low end if they should be between 170 and 210 (especially the 160), but that's certainly higher than the 85-100 mentioned.
... but I still haven't populated the JLH... too much on at uni and work right now ;D
Edited in error Alex
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Post by Deleted on May 26, 2009 21:35:59 GMT
Elliot
They all sound fine. HFE results will vary depending on the actual tester used, and the amount of current it supplies to the Base connection of the transistors. My Transistor tester has 2 different base current settings. : 10uA and 100uA. For everything but big power output devices I use the 10uA Base current setting. (roughly equal to a 9v battery supplying Base current through a 8.2Megohm resistor) Alex
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jonclancy
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Post by jonclancy on Dec 4, 2009 18:22:48 GMT
Phil, I can't open the Excel file - is the site still up? Cheers Jon
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