zenikoy Posted May 21, 2014 Posted May 21, 2014 Anyone here built or using one of these phono pre-amp kits? http://www.altronics.com.au/p/k5513-preamp-riaa-shortform-kit/ I've been looking around for a phono stage to use in addition to one built with my Yamaha A-S500 Integrated amp. Was looking at the usual suspect Rega/Project..etc models up to about $200. Then read some reviews mentioning DIY. I'm fairly handy but my electronics construction is limited to some Dick Smith "Fun Ways to Electronics" kits about 30 years ago. I'm willing to give this one a bash! I'm interested to hear peoples opinions on this kit and the resulting audio output. (Turntable is a Lenco L75 with a Shure m97xe) Some other comments here, which seem poitive so far: http://www.audiokarma.org/forums/archive/index.php/t-337428.html http://diyaudioprojects.com/Chip/Phono-Preamp-Kit/
awty Posted May 22, 2014 Posted May 22, 2014 I'm building the CNC phonostage http://www.lencoheaven.net/forum/index.php?topic=9021.0 You can get the board and build manual from Sachin. Very easy to build, can run off of 2x9volt batteries, most of the bits can be had from element14 (actually have plenty of resistors and a few other bits left over from mine you can have). Plenty of options to change loading and capacitance. Im building the OPS as well to use instead of batteries.
andyr Posted May 22, 2014 Posted May 22, 2014 On 21/05/2014 at 8:13 AM, enikoy said: I've been looking around for a phono stage to use in addition to one built with my Yamaha A-S500 Integrated amp. Was looking at the usual suspect Rega/Project..etc models up to about $200. Then read some reviews mentioning DIY. I'm fairly handy but my electronics construction is limited to some Dick Smith "Fun Ways to Electronics" kits about 30 years ago. I'm willing to give this one a bash! I'm interested to hear peoples opinions on this kit and the resulting audio output. (Turntable is a Lenco L75 with a Shure m97xe) There's a very long thread on DIYAudio about a great-sounding phono stage. See here: http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa.html Regards, Andy
oldrose Posted May 22, 2014 Posted May 22, 2014 I'd skip the altronics kits, having built a few of their other kits for learning purposes, the quality of parts used is less than stellar. It's far more expensive but have you looked at the Bugle2? 1
zenikoy Posted May 22, 2014 Author Posted May 22, 2014 (edited) Thanks for the replys guys, in the mean time I have bought the Altronics kit (only a lunchbreak stroll away). If the DIY bug bites and the soldering iron and I re-kindle our friendship I'm sure I'll be up for some more of these projects. I love hacks and "homebrew" solutions :-) Worst case would be that it costs $40 to prove I'm cack handed at DIY electronics! Edited May 22, 2014 by enikoy
zenikoy Posted May 25, 2014 Author Posted May 25, 2014 OK, so built. I'm pretty chuffed how it sounds and that I assembled it. Need to put it in a box, but it sounds good with just a circuit board laying on the floor Picking up very minor RF interference/ hum which I hope gets sorted once in an aluminium enclosure. Hard to do a real A to B test switching inputs back and forward. Not hearing anything ugly and its at least as good as the inbuilt unit in the Yamaha A-S500 amp. Most surprising thing was listening to a Miles Davis mono LP, it created quite a soundstage effect, obvioulsy not stereo, but instruments felt spread wider rather than just centred (if you get my drift!). Enjoyed that. So, $57 in so far for kit and power pack (12V AC). Learnt heaps.
zenikoy Posted July 5, 2014 Author Posted July 5, 2014 Well I boxed it and put into use. Very happy with it, $75 down and lots learnt. I'll use it a bit longer then swap back to the integrated's built in phono stage and see how I feel about that again. 1
zog Posted July 5, 2014 Posted July 5, 2014 On 05/07/2014 at 11:19 AM, enikoy said: Well I boxed it and put into use. Nice clean and simple build, great stuff!
zenikoy Posted September 12, 2014 Author Posted September 12, 2014 Been reading about summing L+R channels using RCA Y cables to get the best from MONO recordings (via the Beatles box thread). I'm wondering if another option would be to add/wire in a toggle switch to the pre-amp box discussed here, that would connect the inner pins of the input RCAs, giving the same effect as the external Y cables, but with easy Stereo/Mono switching? Would it be preferable to do this on the input or the output RCAs of the phono pre-amp? I'm handy, but no electrical engineer :-)
Zaphod Beeblebrox Posted September 12, 2014 Posted September 12, 2014 On 12/09/2014 at 3:53 AM, enikoy said: Been reading about summing L+R channels using RCA Y cables to get the best from MONO recordings (via the Beatles box thread). I'm wondering if another option would be to add/wire in a toggle switch to the pre-amp box discussed here, that would connect the inner pins of the input RCAs, giving the same effect as the external Y cables, but with easy Stereo/Mono switching? Would it be preferable to do this on the input or the output RCAs of the phono pre-amp? I'm handy, but no electrical engineer :-) It doesn't much matter, BUT you MUST use resistors to sum left & right channels. The value of the resistors will depend on the output impedance of the source. In general, the best place would be to do it after the phono preamp, using (say) 1,000 Ohm resistors.
zenikoy Posted September 12, 2014 Author Posted September 12, 2014 Thanks Zaph, looks like I will have to think this one through a bit more. In the meantime, do you think that the people using 2 Y RCA cables before the phono pre-amp are doing something unwise? eg 2xRCA (female) to 1xRCA (male) and 1xRCA (female) to 2xRCA (female) connected
catman Posted September 12, 2014 Posted September 12, 2014 (edited) G'day all, just found this thread! Yes I've built two of these kits for different applications and the sound quality is very good. A couple of possible simple modifications. OPA2134 dual op amps sound nice and LM4562's are very nice as well, and if you're using the OEM elliptical stylus Shure M97xE you might try changing the 47 k input resistors to 62 k for slightly improved upper treble. Changing the input loading ceramic capacitors to the same value WIMA polypropylene capacitors is a worthwhile upgrade in my humble opinion. Regards, Felix. Edited September 12, 2014 by catman
zenikoy Posted September 14, 2014 Author Posted September 14, 2014 (edited) Thanks Felix. Is the change in resistors to 62k that you mention,something that you could add in as a secondary equalisation circuit? The PCB has capacity for 3 that can be switched between. Listening to it now and it still sounds great on my system. Switchable EQ and mono/stereo would certainly make it even more useful. Maybe building up another kit with the mods you mentioned and the switching would be the way to go rather than disturbing what I have already set up. Edited September 14, 2014 by enikoy
catman Posted September 14, 2014 Posted September 14, 2014 G'day mate, if changing the input resistance to 62 k, the 47 k input loading resistors need to be changed, not in the equalisation networks. However if it sounds good to you as it already is, then don't bother with any modifications. Regards, Felix. 1
zenikoy Posted September 15, 2014 Author Posted September 15, 2014 On 14/09/2014 at 7:45 PM, catman said: G'day mate, if changing the input resistance to 62 k, the 47 k input loading resistors need to be changed, not in the equalisation networks. However if it sounds good to you as it already is, then don't bother with any modifications. Regards, Felix.Thanks Felix, as you can tell, I have little Idea what I am doing at the moment, other than being good at following instructions and asking many questions. I'll leave good alone :-) I think my system is on the bright side (Yamaha A-S500) so the Shure is maybe a natural match.
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