oldbrowndog Posted January 14, 2018 Share Posted January 14, 2018 Hi all, I am interested in a solution to get a completely muteable SINGLE volume control for my phono preamp, which currently does not have one.. Short of buying another preamp with volume control what is a possible solution that wouldn't negatively affect the signal? My current setup is a musical fidelity x-lps v3 phono preamp running straight into 2 Altec 1569a valve monoblocks powering some altec A7 speakers. I can currently use the volume controls on the Altec monoblocks to cut or raise the levels, but i want to set & forget the monoblocks & have a single volume control. Is there any small unintrusive passive attentuation unit i could use between the preamp & the monoblocks to do this? Prefereably something i can buy off the shelf rather than make myself, though that isn't out of the question... Or last option is to sell the Preamp & buy one with volume control.. suggestions please? Link to comment Share on other sites More sharing options...
andyr Posted January 14, 2018 Share Posted January 14, 2018 (edited) 4 hours ago, oldbrowndog said: Hi all, I am interested in a solution to get a completely muteable SINGLE volume control for my phono preamp, which currently does not have one.. Short of buying another preamp with volume control what is a possible solution that wouldn't negatively affect the signal? My current setup is a musical fidelity x-lps v3 phono preamp running straight into 2 Altec 1569a valve monoblocks powering some altec A7 speakers. From what you describe, you don't have a 'preamp' - you simply have a mf x-lps phono stage running straight into your Altec monoblocs ... which have a volume control. Quote I can currently use the volume controls on the Altec monoblocks to cut or raise the levels, but i want to set & forget the monoblocks & have a single volume control. Good concept in theory ... and having a separate volume control on each power amp gives you a balance control for free - which is a good thing to have! Quote Is there any small unintrusive passive attentuation unit i could use between the preamp & the monoblocks to do this? You could probably find what is called a "passive preamp" (which I consider is an oxymoron, as it doesn't amplify the signal - merely attenuates it!). Whether this would work well or not depends on the Zin of your Altec monoblocs - but being tube, it would probably work OK (having a high Zin). A passive preamp would also have source selection - which you don't seem to want. Quote Or last option is to sell the Preamp & buy one with volume control.. suggestions please? There are not too many phono stages around with an integral volume control. Andy Edited January 14, 2018 by andyr 1 Link to comment Share on other sites More sharing options...
djb Posted January 14, 2018 Share Posted January 14, 2018 I don't think I've never seen a phono stage with a volume control 1 Link to comment Share on other sites More sharing options...
mloutfie Posted January 14, 2018 Share Posted January 14, 2018 what's your budget for the line attenuator (a more accurate term in my book)? we can give a more accurate suggestion then Link to comment Share on other sites More sharing options...
oldbrowndog Posted January 14, 2018 Author Share Posted January 14, 2018 Right you are, my mistake, yes it is only a Phono stage. A passive preamplifier/line attenuator is exactly what I am thinking. As the parts for such a thing would be quite cheap I cant imagine they cost a lot, but then again.....? The ability to send a few separate signals into it would hurt either in case i do decide to play around. Any recommendations on units please.. cost 100 - $250. Link to comment Share on other sites More sharing options...
oldbrowndog Posted January 14, 2018 Author Share Posted January 14, 2018 perhaps this.. though the brand name is a little dubious.. https://addictedtoaudio.com.au/products/schiit-audio-sys-passive-preamp 1 Link to comment Share on other sites More sharing options...
mloutfie Posted January 14, 2018 Share Posted January 14, 2018 The sys would be best for your price point or you can get some similar on Ebay but I would suggest go with schiit Link to comment Share on other sites More sharing options...
VanArn Posted January 14, 2018 Share Posted January 14, 2018 It may be wiser to go a step further, oldbrowndog, and add a source selector switch to your intended system alterations. A phono preamplifier is used in a system when the preamplifier or integrated amplifier is not provided with this facility. I would suggest that buffer stages between the X-lpsv3 and the Altec P.A. amplifiers are needed as the reference output of the phono pre is 300mV and the minimum sensitivity of the amplifier is 900mV. It would be convenient if a source selector switch, stereo volume control and the buffer stages could be installed within the Musical Fidelity's case, although this might not be possible , due to a lack of space. Link to comment Share on other sites More sharing options...
aussievintage Posted January 14, 2018 Share Posted January 14, 2018 15 hours ago, oldbrowndog said: Is there any small unintrusive passive attentuation unit i could use between the preamp & the monoblocks to do this? Prefereably something i can buy off the shelf rather than make myself, though that isn't out of the question... If you decide to make something yourself, the ultra simple way - here's what I did when I had a signal that was too hot once. Get a nice quality interconnect cable, a small box, and a dual gang audio/log taper potentiometer (common despite the name). Value depends on the impedance of the power amps' inputs. Drill a hole in each end of the box, and drill a hole for the pot, cut the cable in two (nearer one end might be more convenient for use later). Insert the cut ends into each end of the box, tieing a knot in each so they can't pull back out. Strip and bare all the cut cable ends and solder to the pot (I can draw up a quick diagram if needed). Mount the pot to the box and close the lid. Fit a nice knob and you're finished. Link to comment Share on other sites More sharing options...
oldbrowndog Posted January 16, 2018 Author Share Posted January 16, 2018 Thanks for those last 2 messages much appreicated, not sure i fully comprehended the message from VanArn but the general drift is source selector switch so i can have different inputs? & a buffer stage to try & match impedances.. Im beginning to think a more relevant preamp for the era of gear im using would be good, & a very simple box like the one aussieventage mentions might be the best option for this setup.. ( the schitt source selector seems like it would be to cheap a unit to use with this tbh).... back to the drawing board. Link to comment Share on other sites More sharing options...
VanArn Posted January 16, 2018 Share Posted January 16, 2018 (edited) A buffer stage is suggested as you require some extra gain ( amplification ) between your phono preamp and your monoblock P.A. amplifiers. Impedance matching is not an issue with your setup. Perhaps a preamplifier having all the features you require would be better suited to your needs rather than a bits and pieces approach. Edited January 17, 2018 by VanArn Typo Link to comment Share on other sites More sharing options...
andyr Posted January 21, 2018 Share Posted January 21, 2018 (edited) On 1/14/2018 at 10:57 PM, oldbrowndog said: Right you are, my mistake, yes it is only a Phono stage. After a discussion this morning with Hugh "Mr AKSA" Dean, I can confirm that I can supply you with one of my 'Muse' phono stages which has a volume control fitted. You would then run your Altec 1569as at max volume (to take their volume controls out of circuit - for best sound). Obviously, this will be a lot more than $100 - 250 ... but you would be able to sell your MF x-lps v3 to part pay for it. I supply the Muse either with MM gain ... or MC gain, but not both (because IMO, having a switch at such low signal levels degrades the sound - compared to not having a switch). PM me if you're interested. Andy Edited January 21, 2018 by andyr Link to comment Share on other sites More sharing options...
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