Erik Mandaville Posted February 19, 2009 Share Posted February 19, 2009 GotHover: "Erik, No the sheild is only connected at the circuit board ground bus and is floated on the VC to reduce ground loop issues. The coax really isn't necessary, but the extra sheilding never hurts." Sure, that makes sense. As I'm sure you already know, there are numerous approaches to grounding, and grounding in general can be perplexing: what works well in one circuit may not necessarily be as equally effective in another. There have been a couple of instances with preamps I've made in the past where a ground plane, surprisingly, turned out to be a better solution (in terms of noise rejection and ground loop potential) than using a ground buss and/or single-point star ground. Those were scratch built line-stages, though, so at the time I wasn't sure about what the best approach would ultimately be. With a little practiced experimentation, it's sometimes possible to also improve on what is called for in a schematic or kit instruction booklet. I agree about the use of shielded cable. At line levels (as opposed to phono inputs), I've gotten away with unshielded cable many times in the past, particularly when tube filaments were heated with well-filtered DC and signal leads were routed away from power supply connections. However, where AC is used on filaments, and where input connections may have to be routed more closely to PSU components, a little shielding, even with line level signals, can be beneficial. I was just curious, thanks for the explanation. Erik Quote Link to comment Share on other sites More sharing options...
Guest David H Posted February 24, 2009 Share Posted February 24, 2009 Erick, thanks for sharing that info, I didn't realize there were so many ground configuration possibilities. I have always stuck with single point grounding, an have had good results. Quote Link to comment Share on other sites More sharing options...
Marvel Posted February 24, 2009 Share Posted February 24, 2009 A very sweet looking build! I'm getting ready to swap out my Curcio ST-70 board for one of Roy's It's gonna be fun. Bruce Quote Link to comment Share on other sites More sharing options...
Guest David H Posted February 27, 2009 Share Posted February 27, 2009 A very sweet looking build! I'm getting ready to swap out my Curcio ST-70 board for one of Roy's It's gonna be fun. Bruce Good choice, I love my VTA 70. May I suggest going with the Auricap upgrade. You will love it. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted March 5, 2009 Share Posted March 5, 2009 Great new for those interested, Tubes4HiFi has a bunch of new DIY products. The SP-8 preamp with regulated heater and B+. New heavy duty torroidal transformer for DIY and Dynaco Pas upgrades. Lastly VTA is offering a preamp linestage only no phono. Quote Link to comment Share on other sites More sharing options...
The Dude Posted March 13, 2009 Share Posted March 13, 2009 Nice looking piece, looks like i picked the right time to get started on a 2 channel system glad this forum is around to get people started in the path on audio. As i like to think to start with something like this to learn and enjoy, especially for the price. Can't wait to get started. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted March 14, 2009 Share Posted March 14, 2009 Duder, I think you will like this preamp, and Roy at Tubes4HiFi is great to deal with... Have fun, and send me a pm if you need more info. Quote Link to comment Share on other sites More sharing options...
The Dude Posted March 25, 2009 Share Posted March 25, 2009 I just picked up a pat-4 pre-amp off of ebay though the guy said it works great and which i am sure it does(havent got the chance to check it out yet) but i mainly got it for the chassy.. I cant wait until i start dumping some of those up grades in it. it might take me a couple of months but that gives me time to finish working on my amp for this bad boy, and save some bucks for some Cornwalls ide like to but in the system. Speaking of which if anyone recomends any certain Cornwalls as far as 1 or 2s go with any updates let me know that will be the next thing i do for this two channel set up. nick Quote Link to comment Share on other sites More sharing options...
Guest David H Posted March 25, 2009 Share Posted March 25, 2009 Nice choice, I always liked the idea of putting the upgrade in an original Dynaco chassis. You will also be able to really appreciate the improvement over the stock PAT-4. As for Cornwalls either version works well, I am currently working with JWCullison on a pair of Tractrix midhorns for Cornwalls. Cornwall upgrades will depend on the age, model and possible issues you may have with them. There are some really good upgrades for older Cornwall 1's. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted March 25, 2009 Share Posted March 25, 2009 the PAT 4 is solid state....no tubes in it. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted March 26, 2009 Share Posted March 26, 2009 the PAT 4 is solid state....no tubes in it. You couldn't be more right, but the chassis is perfect for the Tubes4HiFi SP-6 or SP-8 board and upgrade.Here is a pic of the SP-6 installed in a Pat-4 Quote Link to comment Share on other sites More sharing options...
Guest " " Posted March 26, 2009 Share Posted March 26, 2009 Amazing...... Quote Link to comment Share on other sites More sharing options...
The Dude Posted March 26, 2009 Share Posted March 26, 2009 and thats what i want to build. man am i geeking out. Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 19, 2012 Share Posted April 19, 2012 So 3 years later, I finally pulled the trigger on Roys sp6. Originally I was going to order the sp8 but it has been replaced with a line stage only kit. Yes Roy is wonderful to talk to and great customer service. I started off just ordering the sp 6 line stage board, but after talking to Roy he recommended a regulated power supply with a toroid transformer, plus he made me a offer I couldn't refuse. I will be starting my own build thread once I get some other things done. Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 19, 2012 Share Posted April 19, 2012 I am still plaining on stuffing this in the Pat4 chassis, but I must say once I add the phono stage"were going to need a bigger boat" Quote Link to comment Share on other sites More sharing options...
Guest David H Posted April 20, 2012 Share Posted April 20, 2012 Nice, enjoy your project., Doesnt the sp-6 have a phono stage on board? Dave Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 20, 2012 Share Posted April 20, 2012 Not any more he split the board to fit in the pas3 as a drop in replacement. Quote Link to comment Share on other sites More sharing options...
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