C-Audio Pulse Projects
Printed From: Speakerplans.com
Category: General
Forum Name: Amp Forum
Forum Description: The 'Stopping Jake Fielder moaning constantly' forum description...
URL: https://forum.speakerplans.com/forum_posts.asp?TID=106433
Printed Date: 26 March 2026 at 9:25pm
Software Version: Web Wiz Forums 12.08 - https://www.webwizforums.com
Topic: C-Audio Pulse Projects
Posted By: ceharden
Subject: C-Audio Pulse Projects
Date Posted: 30 July 2021 at 12:16am
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Just wondering if anyone might be interested in some partially or non-working C-Audio Pulses as spares or repair projects? I have been running Pulse 2x1100's on my own system for years and sound-wise I really like them. However I am starting to move over to slightly more modern designs for various reasons. That means it's probably unlikely I will ever get round to finish looking at the ones which are long term residents in my workshop. I have one 2x1100 very much in bits which needs a complete output stage rebuilt and realistically may be no longer worth the effort and a 2x650 which is essentially working but suffers from a switch on/off thump on the output which I have never managed to track down the cause of. There is also another 2x1100 on the shelf which I've spotted an issue with the rail commutation where there is a brief oscillation but I can't decide if it's actually a fault with or it's just a design feature I've never paid attention to before! In addition, I also have a number of fully working 2x1100's which I should consider selling if anyone fancies a couple. |
Replies:
Posted By: Phil B
Date Posted: 30 July 2021 at 12:30am
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I would love the 2 x 650 for spares but I think the air freight will be more than it's worth !! .p. ------------- Mostly harmless.... except if catering is shut. Solar Sound System Shennanigans.. http://diyhifi.biz/" rel="nofollow - http://diyhifi.biz/ |
Posted By: ceharden
Date Posted: 30 July 2021 at 12:33am
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Shame, even container shipment is expensive at the moment. |
Posted By: M4trix
Date Posted: 30 July 2021 at 9:46pm
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Interesting. So far I've only seen Yorkville using TO-3 ( MJ ) devices in their class-H amplifiers. @Ceharden, would you be so kind and tell me the power supply voltages HT/MT ? Cheers. Edit: for the 1100 model please.
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Posted By: ceharden
Date Posted: 30 July 2021 at 11:55pm
| They're approximately 70 and 140V from memory, been a while since I've measured them. |
Posted By: M4trix
Date Posted: 31 July 2021 at 12:35am
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Thanks mate.  |
Posted By: M4trix
Date Posted: 31 July 2021 at 9:31pm
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*bumpinator Edit:
Since I have a bunch of NOS MJ15022/23, I was thinking to clone this
amplifier for fun. I don't want to waste all these transistors for
nothing especially I don't want them discarded. Over 100 matched devices.  Those voltages are too high for them so I have to adapt the whole project. Full SMD conversion except power resistors etc. And those silly ZTX transistors... get out of my sight !
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Posted By: ceharden
Date Posted: 31 July 2021 at 9:39pm
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You could do something along the same lines quite easily, just reducing the supply Voltages.
I have often considered doing my own version, incorporating all the known issues, especially in the PSU. Never going to have the time though. |
Posted By: M4trix
Date Posted: 31 July 2021 at 11:07pm
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Will come out with the schematic. I'm currently having problems with finding proper transistors. BF422/BF423 are way obsolete. Any suggestions ? Edit: MJE5731A/TIP50 are going out as well. MJE15032/MJE15033 will do the business. Edit 2: Vbe multiplier, TTA006B ( 2SA1837 ) Edit 3: these might replace BF422/423 --> BF722/BF723 or BF720/721 |