tag:blogger.com,1999:blog-2098337119765190876.post7390201801801618840..comments2024-03-28T13:34:32.307+01:00Comments on VinylSavor: Making of a D3a LCR RIAA Phono Preamp - Part 1VinylSavorhttp://www.blogger.com/profile/03255472557028244395noreply@blogger.comBlogger19125tag:blogger.com,1999:blog-2098337119765190876.post-236622435430291672021-05-05T22:06:24.144+02:002021-05-05T22:06:24.144+02:00Thomas, I completely understand.
I am building a...Thomas, I completely understand. <br /><br />I am building a very similar LCR EQ phono preamp, and yes, I intend to use it as the basis for testing certain variations, etc., of the circuit.<br /><br />All the Best!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-6637352622971139252021-05-05T20:41:04.199+02:002021-05-05T20:41:04.199+02:00I am sorry but that circuit is not public. Why doe...I am sorry but that circuit is not public. Why does it matter anyways? Why don't you try the idea you wrote above and see how it works for youVinylSavorhttps://www.blogger.com/profile/03255472557028244395noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-66868479373262136612021-05-05T20:35:08.217+02:002021-05-05T20:35:08.217+02:00Hi Thomas,
Thank you for your reply!
How did you...Hi Thomas,<br /><br />Thank you for your reply!<br /><br />How did you change and improve the electrical design in 2015, with regard to the biasing scheme for the D3As? How are you now biasing the D3As? And are you still using the Ultrapath topology in this LCR EQ phono preamp?<br /><br />Thanks in advance!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-81986280795195673792021-05-05T06:18:37.834+02:002021-05-05T06:18:37.834+02:00Hi!
This is an old version of my pono design which...Hi!<br />This is an old version of my pono design which I changed substantially in 2015. I am not using LED bias but you can of course try it and see how it works for youVinylSavorhttps://www.blogger.com/profile/03255472557028244395noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-14370548465970419942021-05-05T05:34:59.564+02:002021-05-05T05:34:59.564+02:00Hello Thomas.
Looking at the layout of this D3A L...Hello Thomas.<br /><br />Looking at the layout of this D3A LCR phono preamp, it appears that perhaps you are using a combination of the classic Ultrapath circuit, and a high value electrolytic capacitor across the cathode resistor from each of the D3A cathodes to ground. I assume the electrolytic is to suppress what would otherwise be a substantial issue with power supply ripple (hum) in this circuit, even with a well-filtered power supply, being that the D3A is are relatively high-mu tube, and they will amplify the ripple by mu+1. Are my assumptions correct?<br /><br />If so, have you perhaps tried LED bias with these tubes in this LCR phono preamp circuit? LEDs may be good candidates for this particular application; approximately 20 Ma cathode current per tube, and a low cathode bias voltage of around 1.7 VDC or so. The use of the LEDs would of course eliminate any need to bypass the cathode resistors with a capacitor, etc.<br /><br />What are your thoughts on this?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-22406188863791877852013-07-27T15:44:49.703+02:002013-07-27T15:44:49.703+02:00Yes I did, but prefer the intactaudio coilsYes I did, but prefer the intactaudio coilsVinylSavorhttps://www.blogger.com/profile/03255472557028244395noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-73697583796952990322013-04-04T11:37:16.219+02:002013-04-04T11:37:16.219+02:00Thanks Thomas, much appreciated, that makes me mor...Thanks Thomas, much appreciated, that makes me more confident that mine should be ok!<br /><br />Beautiful build, BTW, I love your style.<br /><br />Cheers,<br />PetePiotr Ghttps://www.blogger.com/profile/13514833742991618799noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-15859505920142814632013-04-04T11:19:48.626+02:002013-04-04T11:19:48.626+02:00Hi Pete,
no screening necessary. This phono is ve...Hi Pete,<br /><br />no screening necessary. This phono is very quiet even if used with a MC cartridge without MC step up transformer. Just keep enough distance to the PSU. half a meter is enough.<br /><br />ThomasVinylSavorhttps://www.blogger.com/profile/03255472557028244395noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-65581314702395991012013-04-04T10:25:56.101+02:002013-04-04T10:25:56.101+02:00Hi Thomas, I'm building something similar, :-)...Hi Thomas, I'm building something similar, :-) Did you find any need to screen the inductors?<br /><br />Thanks,<br />Pete<br />Piotr Ghttps://www.blogger.com/profile/13514833742991618799noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-22689211333264489902013-02-25T17:24:45.914+01:002013-02-25T17:24:45.914+01:00Thanks, Thomas.
At first I thought you are using ...Thanks, Thomas.<br /><br />At first I thought you are using O-Rings but I noticed it is a single rubber element. It is pretty good machining of blind holes if you can only use a 4mm plate.<br /><br />Regards,<br /><br />TonyAnonymoushttps://www.blogger.com/profile/02744075829270932620noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-27429612562378324942013-02-25T17:01:28.084+01:002013-02-25T17:01:28.084+01:00Hi Tony,
The rubber elements are from a local sup...Hi Tony,<br /><br />The rubber elements are from a local supplier. The impact of the ground wire on damping is minimal. If the sub plates damping is too soft, it is not effective in absorbing vibrations.<br /><br />The plates are 4mm thick<br /><br />Best regards<br /><br />ThomasVinylSavorhttps://www.blogger.com/profile/03255472557028244395noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-39376544526845688262013-02-25T16:42:11.887+01:002013-02-25T16:42:11.887+01:00Very nice, Thomas!
I wonder what rubber parts are...Very nice, Thomas!<br /><br />I wonder what rubber parts are you using to decouple the small tube plates? I noticed you use thicker solid core wires for ground for the tubes. Will these thick wires decrease isolation of the tubes?<br /><br />I like very much that no screws are visible from the top due to use of the blind tapped holes. What thickness of the top plates are you able to get away with? 5mm?<br /><br />Regards,<br /><br />TonyAnonymoushttps://www.blogger.com/profile/02744075829270932620noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-18356049757312027412013-02-12T10:42:40.333+01:002013-02-12T10:42:40.333+01:00There is a beauty coming up :-)There is a beauty coming up :-)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-15018059484822625002013-02-10T01:00:47.160+01:002013-02-10T01:00:47.160+01:00Thomas,
Have you tried the Lundahl LCR Inductors?...Thomas,<br /><br />Have you tried the Lundahl LCR Inductors?<br /><br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-40436333579493282842013-02-09T18:34:56.336+01:002013-02-09T18:34:56.336+01:00Hi Pedro,
I can supply everything needed for this...Hi Pedro,<br /><br />I can supply everything needed for this preamp.<br />The important parts are the signal transformers and LCR coils.<br />Also the power supply chokes and I believe the power transformers are very important.<br />I can also provide the capacitors. <br /><br />You can also get a subset of parts for example if you have a specific preference for caps and want to use others or if you have a LCR network already.<br /><br />Schematics will be provided also with a subset of the parts. I will also be available for consulting during the construction in case of any questions.<br /><br />Contact me be email: thomas -at- vinylsavor -dot- de<br /><br />Best regards<br /><br />ThomasVinylSavorhttps://www.blogger.com/profile/03255472557028244395noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-46033477099202731412013-02-09T17:13:04.650+01:002013-02-09T17:13:04.650+01:00dear Thomas,
could you please let us know the stra...dear Thomas,<br />could you please let us know the strategic parts you can supply for this phono ?<br /><br />best regards,<br />Pedro<br />alicante(costa blancaAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-924017511128113142013-02-08T23:47:37.566+01:002013-02-08T23:47:37.566+01:001A 1A1A 1AAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-17124855231178060242013-02-08T19:28:52.216+01:002013-02-08T19:28:52.216+01:00Hi!
This phono stage is available as a kit or par...Hi!<br /><br />This phono stage is available as a kit or partial kit. Schematics will be provided with the purchase of parts. Gotta keep at least some secrets ;-)<br /><br />ThomasVinylSavorhttps://www.blogger.com/profile/03255472557028244395noreply@blogger.comtag:blogger.com,1999:blog-2098337119765190876.post-89081034898655312512013-02-08T19:08:21.849+01:002013-02-08T19:08:21.849+01:00Great!
Can we see schematic?
I tried to find every...Great!<br />Can we see schematic?<br />I tried to find everywhere but with no success :(neskorhttps://www.blogger.com/profile/10439527934457026505noreply@blogger.com