Post by optical on Jul 26, 2022 11:04:36 GMT
Not strictly DIY (as the finished product has been bought and modified) but you can buy the boards and chassis separately also.
So,
a couple of years ago I bought the identical phono stage from Ali Express, no recommendations, no reviews.
I was aware that the circuit it was based on was pretty highly regarded (D.Klimo) so after a little research I pulled the trigger.
The brief here was to have a decent quality valve phono stage with switchable MM/MC inputs where no swapping of cables was necessary to have full use of both an MM and MC turntable.
It arrived and to be honest sounded very good in it's standard guise.
I'd been perfectly happy modifying an EAR834 clone phono stage, nothing complicated just replacing a couple of caps for some Mundorf Supreme's. (Alan Firebottle has a great little mod for these which he carried out). But I wanted to use an MC cart in another turntable and the EAR clone was MM input only. I did use an SUT for a while but ultimately the inconvenience of switching cables or adding a 2-1 switchbox was becoming tiresome and I wanted a more elegant solution.
Boyed by the success of the cap upgrades in the EAR clone I did similar with the new one, swapping the big caps once again for Supreme's but also replacing the smaller ones in the circuit with some Clarity SA's.
The valves were upgraded to some Philips/Mullard 12AT7's along with some Voskhod Rocket 6n23p's. The rectifier was replaced by a Tung-Sol 6x4WA with an adapter.
It all came together even though the board was an absolute pig to work on without desoldering all of the connections from the transformer, which I didn't want to do.
To be honest I was blown away by the sound. Not only that but it was dead silent (after isolating the transformer a bit to stop it buzzing) but there was no switching noise between MM/MC and no background hum at all. Overall just a winner.
So obviously I sold it.
Idiot, thought I could do better but ultimately it was always a sideways move when I 'upgraded'. Okay so I had a very nice phono stage recently (again which I've sold) but it was also MM only, so I didn't really learn my lesson there did I!
Anyway, I've been thinking about what the original phono stage did wrong and the answer is very little, so the chance came to get another for cheap on Ali Express so I bought it.
Bought all the bits to go with it as I waited for it to arrive.
Opened it up upon arrival, oh dear. Looks like the manufacturing costs have squeezed the parts quality a bit. Previously the original one came with some decent CMC 'rose gold' (red copper) RCA sockets for all inputs and outputs. This one had some very cheap and nasty brass offerings. Oh well a bit more added cost but I ordered some pure copper CMC ones as I wasn't about to build the same stage again, only slightly inferior.
Transformer was rated to 230v so this was nice to see as some of the Chinese bought goods can sometimes be 220v which can cause some issues with UK voltages.
Got straight to work on it desoldering the old caps and drilling holes in the board to accommodate the (thicker lead out wired) new ones.
Finished in a couple of hours but had some issues soldering properly to the thin track which lifted easily so used some OCC wire to go point to point on some components (didn't actually realise you have to scrape off the protective film of the track to get a good surface to work with, oops).
Committed the cardinal sin of not listening to it first but my previous efforts had gone so well what could possibly go wrong . . . . well something actually.
I got it home, new caps in place (sockets hadn't arrived yet so hadn't done them), switched it on . . . nowt, nothing, not even an electrical thump or pop switching it on whilst connected to the system with the volume up. That's not good.
Traced the circuit as best I could but couldn't rectify it.
Time to call in the experts . . . . so off it goes to Alan 'get a guy out of the sh**' Firebottle . . . . pride slightly swallowed now.
Alan immediately saw I'd re-soldered one of the output pins incorrectly. Oh well, so much messing about with stuff without a huge amount of knowledge was bound to end me up in some sort of mess sooner or later, it happens.
Alan had a little listen before making any major changes and without putting words in his mouth I think he was quite surprised. Glad I wasn't just imagining it then . . .
Further to my embarrassment I'd also used the wrong value for the smaller caps, they were okay on the MM part of the circuit but not for the MC. Luckily Alan had some nice Le Clanché Signal Path caps which could replace the wrong ones and probably do a better job in that position anyway.
After rectifying it Alan set about further improving things. Adding some resistors in the power section to bring the noise floor down further (I think).
The CMC sockets were added and the stage has now made it's way back to me.
Haven't had a listen yet but I have no doubt it will be a vast improvement over the original one I had which in itself was pretty darn good.
Big thanks to Alan for getting me out of the brown stuff on this.
So,
a couple of years ago I bought the identical phono stage from Ali Express, no recommendations, no reviews.
I was aware that the circuit it was based on was pretty highly regarded (D.Klimo) so after a little research I pulled the trigger.
The brief here was to have a decent quality valve phono stage with switchable MM/MC inputs where no swapping of cables was necessary to have full use of both an MM and MC turntable.
It arrived and to be honest sounded very good in it's standard guise.
I'd been perfectly happy modifying an EAR834 clone phono stage, nothing complicated just replacing a couple of caps for some Mundorf Supreme's. (Alan Firebottle has a great little mod for these which he carried out). But I wanted to use an MC cart in another turntable and the EAR clone was MM input only. I did use an SUT for a while but ultimately the inconvenience of switching cables or adding a 2-1 switchbox was becoming tiresome and I wanted a more elegant solution.
Boyed by the success of the cap upgrades in the EAR clone I did similar with the new one, swapping the big caps once again for Supreme's but also replacing the smaller ones in the circuit with some Clarity SA's.
The valves were upgraded to some Philips/Mullard 12AT7's along with some Voskhod Rocket 6n23p's. The rectifier was replaced by a Tung-Sol 6x4WA with an adapter.
It all came together even though the board was an absolute pig to work on without desoldering all of the connections from the transformer, which I didn't want to do.
To be honest I was blown away by the sound. Not only that but it was dead silent (after isolating the transformer a bit to stop it buzzing) but there was no switching noise between MM/MC and no background hum at all. Overall just a winner.
So obviously I sold it.
Idiot, thought I could do better but ultimately it was always a sideways move when I 'upgraded'. Okay so I had a very nice phono stage recently (again which I've sold) but it was also MM only, so I didn't really learn my lesson there did I!
Anyway, I've been thinking about what the original phono stage did wrong and the answer is very little, so the chance came to get another for cheap on Ali Express so I bought it.
Bought all the bits to go with it as I waited for it to arrive.
Opened it up upon arrival, oh dear. Looks like the manufacturing costs have squeezed the parts quality a bit. Previously the original one came with some decent CMC 'rose gold' (red copper) RCA sockets for all inputs and outputs. This one had some very cheap and nasty brass offerings. Oh well a bit more added cost but I ordered some pure copper CMC ones as I wasn't about to build the same stage again, only slightly inferior.
Transformer was rated to 230v so this was nice to see as some of the Chinese bought goods can sometimes be 220v which can cause some issues with UK voltages.
Got straight to work on it desoldering the old caps and drilling holes in the board to accommodate the (thicker lead out wired) new ones.
Finished in a couple of hours but had some issues soldering properly to the thin track which lifted easily so used some OCC wire to go point to point on some components (didn't actually realise you have to scrape off the protective film of the track to get a good surface to work with, oops).
Committed the cardinal sin of not listening to it first but my previous efforts had gone so well what could possibly go wrong . . . . well something actually.
I got it home, new caps in place (sockets hadn't arrived yet so hadn't done them), switched it on . . . nowt, nothing, not even an electrical thump or pop switching it on whilst connected to the system with the volume up. That's not good.
Traced the circuit as best I could but couldn't rectify it.
Time to call in the experts . . . . so off it goes to Alan 'get a guy out of the sh**' Firebottle . . . . pride slightly swallowed now.
Alan immediately saw I'd re-soldered one of the output pins incorrectly. Oh well, so much messing about with stuff without a huge amount of knowledge was bound to end me up in some sort of mess sooner or later, it happens.
Alan had a little listen before making any major changes and without putting words in his mouth I think he was quite surprised. Glad I wasn't just imagining it then . . .
Further to my embarrassment I'd also used the wrong value for the smaller caps, they were okay on the MM part of the circuit but not for the MC. Luckily Alan had some nice Le Clanché Signal Path caps which could replace the wrong ones and probably do a better job in that position anyway.
After rectifying it Alan set about further improving things. Adding some resistors in the power section to bring the noise floor down further (I think).
The CMC sockets were added and the stage has now made it's way back to me.
Haven't had a listen yet but I have no doubt it will be a vast improvement over the original one I had which in itself was pretty darn good.
Big thanks to Alan for getting me out of the brown stuff on this.
