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JLH 10 Watt class A amplifier
JLH 10 Watt class A amplifier
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Old 18th September 2020, 08:50 AM   #7061
nigel pearson is offline nigel pearson  United Kingdom
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Location: Shaftesbury
I think I would use Darlingtons if Dinsdale.
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Old 18th September 2020, 10:06 AM   #7062
OldDIY is offline OldDIY
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Join Date: Dec 2009
Quote:
Originally Posted by Steve Luck View Post
Hi Guys i'm going to build some of these for my desk and possibly my sisters dining room:

DECWARE Tiny Radials


LP Spirit Pure Class A 1969 Amplifier Computer Desktop Mini Merge Split Type HIFI Audio Power Amp|audio power|power ampa class amplifier - AliExpress



Its Based on 1969 John Linsley Hood Design
You are being deceived
2x12 W with a consumption of 27 W pure class A?
Not less than 100 W (transformer 200 W)
Output on transistors TIP41. The radiator is small. This is 2x5 watts. (:
Capacitors 25 V 30,000 microfarads (30x1000). Supply voltage no more than 24V. Nothing is said about the load resistance. You may have to configure it yourself.

Last edited by OldDIY; 18th September 2020 at 10:24 AM.
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Old 18th September 2020, 10:08 AM   #7063
nigel pearson is offline nigel pearson  United Kingdom
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Join Date: Mar 2007
Location: Shaftesbury
I noticed 85C very standard capacitors. Make them 105C and be sure the ripple current is x >2 the actual.
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Old 19th September 2020, 05:14 AM   #7064
Steve Luck is offline Steve Luck  New Zealand
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Join Date: Sep 2012
Location: Wellington
Thanks for the feedback :-)

Not worried about the output provided it's less than 20 watts per channel - any more than that will blow up the drivers in the speakers i'm going to build. Decaware Tiny Radials use some wicked little Tangband 4 Ohm drivers with built in passive radiators so should be OK for intended use. It's for desktop use I'll let you know how i get on- best part is that a lack of surface mount components should make it easy to tweak at a later date.

264-938--tang-band-t2-2136sa-spec-sheet.pdf
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Old 19th September 2020, 05:52 AM   #7065
Ian Finch is offline Ian Finch  Australia
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Join Date: Apr 2010
Location: Coffs Harbour, NSW
JLH 10 Watt class A amplifier
There are several other standard 10W models available from China that are also complete, working and fitted in a single box for less money than that. None that I'm aware of have a preamp included but unless you are a vinyl addict, the JLH'69 and updated versions don't really need one.

Why not DIY build the amplifier though, starting with a super cheap PCB and parts that will be fine for the purpose of getting you going and enthusiastic about the electronics too?
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Old 19th September 2020, 06:59 AM   #7066
Steve Luck is offline Steve Luck  New Zealand
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Join Date: Sep 2012
Location: Wellington
Hi Ian

Thanks :-)

I've already built two ACA and the Korg Nutube all with dedicated power supplies. I have the boards and main case for a Pearl two phono preamp as well that I need to finish. On this occasion I wanted something ready made and cheaper than the ACA that will fit in a specific spot on my desk. I may well pass it on to my sister so keeping it compact and visually appealing comes into the equation for that too.

Will try it out on the horns for a laugh -106db per Watt and powered subwoofers in each to boot :-) In common with Decaware ones - no crossover the subwoofer is just adjusted to cut off at the overlap.
IMG_0714.jpg
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Old 19th September 2020, 07:42 AM   #7067
Ian Finch is offline Ian Finch  Australia
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Join Date: Apr 2010
Location: Coffs Harbour, NSW
JLH 10 Watt class A amplifier
There are a couple of small footprint, cheaper prebuilt models but I suspect they all run quite hot to the touch. I would be wary of passing any class A amplifier on to a family member or friend since being in contact with heatsinks or the case surrounding internal heatsinks, can be painful, even if not hot enough to burn you. Not everyone welcomes a surprise like that when fumbling about with their audio system, connectors and leads at the rear etc. I still get caught out, even after many years of messing with class A.
e.g. 1969 classic Circuit design class A HIFI power amplifier with full aluminum chassis|hifi power amplifier|a class amplifieramplifier a class - AliExpress
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Old 19th September 2020, 07:55 AM   #7068
nigel pearson is offline nigel pearson  United Kingdom
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Location: Shaftesbury
I would be very interested to know if the PSU is OK on hum. Even though it looks impressive it might be marginal. I guess they did their homework. In a way if if does work the simplicity is helpful.
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Old 19th September 2020, 10:47 AM   #7069
OldDIY is offline OldDIY
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Join Date: Dec 2009
Quote:
Originally Posted by Steve Luck View Post
Thanks for the feedback :-)

Not worried about the output provided it's less than 20 watts per channel - any more than that will blow up the drivers in the speakers i'm going to build. Decaware Tiny Radials use some wicked little Tangband 4 Ohm drivers with built in passive radiators so should be OK for intended use. It's for desktop use I'll let you know how i get on- best part is that a lack of surface mount components should make it easy to tweak at a later date.

Attachment 876937
SENSITIVITY 1W/1m 80 dB
POWER RECOMMENDED 20W (RMS)
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Old 19th September 2020, 11:10 AM   #7070
Steve Luck is offline Steve Luck  New Zealand
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Join Date: Sep 2012
Location: Wellington
Decaware have been running the Tangbands on 3 watt Zen Triode amps in all the videos they've posted - I can only assume poor data sheet wording and it means the max recommended is 20 watt which makes more sense for such a tiny driver. Put in perspective the speakers are only 6 1/2 inches tall.
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