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Post by PinkFloyd on Feb 15, 2016 21:14:39 GMT
For £13 you just cannot go wrong and these little amps can prove to be seriously good fun, almost addictive, when it comes to rolling opamps and experimenting with different "flavours" of caps. The power supply couldn't be simpler or cleaner.... a 9V battery and some of the most enjoyable listening sessions I have had have been through an RA1 / CMOY type amp. Who's up for joining the RA1 / CMOY revisited party? The entry fee is £13 shipped: www.ebay.co.uk/itm/221747059163 I chose that particular seller because he's £13 GBP shipped..... no other reason, we can add our own flavours to the mix this is a good starter package IMO. Well....... I'm in, I hit the buy it now button 20 minutes ago and am looking forward to rediscovering the simplicity / bang for the buck / sheer fun of the RA1 / surprisingly superb sound quality / CMOY! When you start scratching your head wondering why things are no longer exciting you tend to look back to simpler times........ these little amps ALWAYS brought a smile to my face and will, undoubtedly, do so again. If you want to be a part of the rockgrotto RA1 / CMOY revisited revolution then I suggest you RUN (don't walk) to your nearest BIN button and hit it hard! Mike.
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Post by PinkFloyd on Feb 15, 2016 21:19:53 GMT
Looking at the PCB it will also accommodate an ALPS RK27 (blue velvet) as well as the mini pot...... I'm looking forward to maxing out this puppy
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jc
Fully Modded
Posts: 5,417
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Post by jc on Feb 24, 2016 22:52:04 GMT
Any news from Guangdong Province?
I wonder if a bodged split rail etc. can be bolted on? A cmoy-stein monster!
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Post by PinkFloyd on Feb 26, 2016 10:00:30 GMT
Any news from Guangdong Province? I wonder if a bodged split rail etc. can be bolted on? A cmoy-stein monster! Hi Chris, It's been shipped but no sightings as yet! Mike.
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Post by PinkFloyd on Mar 10, 2016 20:15:30 GMT
It has arrived but I'm a bit puzzled.......... The RA-1 amp uses a 464K resistor but this clone amp comes with a 464R resistor..... that's a big difference! The question is, what would you guys say was the correct value..... 464K or 464R? Here is the supposedly "correct" RA-1 schematic: Here is the clone RA-1 schematic: Both of them are from third parties so either one could be correct or both could be incorrect Here is a close up of the PCB.... it's a nice quality "weighty" double sided job: I'll upload photos tomorrow of the entire kit contents and then get round to putting it all together but my first priority is to establish the age old question....... "464K or 464R"?
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Deleted
Deleted Member
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Post by Deleted on Mar 10, 2016 23:36:01 GMT
Mike Obviously, the marked 464R in this antiquated circuit, which uses way too high resistor values in the input and feedback areas ,should be 464K which will give a gain of a little under 4 times.
Alex
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Post by PinkFloyd on Mar 11, 2016 20:44:21 GMT
Mike Obviously, the marked 464R in this antiquated circuit, which uses way too high resistor values in the input and feedback areas ,should be 464K which will give a gain of a little under 4 times. Alex Hi Alex, Glad you confirmed that mate.... there are tons of these out there and god only knows what they sound like with the 464R resistor fitted Yes, It may be antiquated and not cutting edge but at £13 GBP shipped it gives people the opportunity to hear the Grado RA-1 amp without having to fork out £420 GBP www.nintronics.co.uk/Headphones/headphone-accessories/headphone-amplifiers/grado-ra1-headphones-amp.html?Colour=12866&gclid=CKvh8s2-ucsCFdS7Gwod_jEE3AWe all know that the Grado RA-1 is this simple, antiquated circuit potted inside a wooden box but a lot of people seem to like it...... they will like it a lot more if all it costs them is £13 (plus wooden casket of their choosing) Strip her down and have a look at what the £420 GBP is buying you: Ooh err missus!
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jc
Fully Modded
Posts: 5,417
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Post by jc on Mar 12, 2016 0:56:19 GMT
Don't speak too loud Mike, someone will be popping these into polished wooden boxes, dub them RA-1 MKii and flog them for a "bargain" £300!
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