Post by RdM on Feb 24, 2021 21:38:34 GMT 12
Just browsing, found this:
Not exactly a manufacturer, but kudos to him for putting the page up and showing us his work!
Atrad-Audio
Post by michaelw on Feb 25, 2021 9:56:26 GMT 12
Looks good !
Balanced output on a tube pre is fancy stuff. My old high school form teacher would have some stern words for the front row of preamp tubes... Stand up straight laddie ! 
5,578 posts |
Post by cartridgeguyonline on Feb 25, 2021 19:08:14 GMT 12
Theres actually a school of thought that believes that preamp valves should lay flat (horizontal). I think I read that in David Manleys book.
941 posts |
Post by RdM on Feb 25, 2021 19:23:28 GMT 12
A friend of mine has made a prototype and ordered boards for a valve preamp with valves horizontally out L&R sides of the chassis.
Very old school, not even on the net at home. It's phone to talk & visit. Time I caught up with him again! 
1,284 posts |
Post by michaelw on Feb 25, 2021 19:35:39 GMT 12
My old Counterpoint SA-7 had horizontal valves that allowed a slim form factor but may have also contributed to the model's legendary unreliability ?
The followup model SA-1000 returned to conventional vertical orientation.
5,578 posts |
|
Connoisseur
 Post by RdM on Feb 25, 2021 20:02:13 GMT 12The followup model SA-1000 returned to conventional vertical orientation. Correlation is not necessarily causation, you know that! Tough review here on a quick glance: I had to go to image search to see internal horizontally mounted tubes/valves. My (mad?) friend has them mounted externally as a feature. Not sure if marble was involved or not, now... cosmetics. Well, perhaps we'll see later. ;=})
1,284 posts |
Post by michaelw on Feb 26, 2021 12:54:19 GMT 12
True but you can't argue against the empirical evidence
 That Stereophile review is indeed brutal, they liked the SA-7 more across the Atlantic, although I recall Ken Kessler writing that the preamp is so microphonic he could shout at it and hear his voice come through the speakers lol I quite enjoyed mine (more musical than a Musical Fidelity The Preamp) until I fitted a factory mod (based on the newer SA-1000 circuit) that removed tubes form the line stage and turned it into a Frankenstein hybrid. But it made it sound worse, so I traded the SA-7 for a used ARC SP8/II I don't recall reading anything in the Manley book about tube orientation, will have a look next time I see the books. The early VTL preamps did lay their tubes down but later models went to conventional stand up fitment.
5,578 posts |
|
Administrator
 Post by Owen Y on Feb 26, 2021 14:05:54 GMT 12
Many valves, esp more modern ones, could operate vertical or horiz.
6DJ8s, no problem, a rugged modern low-noise tube. The Counterpoint SA-7 was a cost-cut design, it was noisy, but not the fault of the tubes. the SA-3 fixed that (also horiz 6DJ8s), eg with 'elevated' heater supply... but didn't sound so 'exciting'. PS. Some tubes must have their plates rotated vertical if operated in a horiz position - more for heat dissipation I'm guessing DarkLantern blog - darklanternforowen.wordpress.com
7,244 posts |
Post by cartridgeguyonline on Feb 26, 2021 16:28:57 GMT 12
All the VTL preamps I was familiar with had them laying horizontal, as did my Melos. ARC had them vertical as did Sonic Frontiers iirc, My current preamp ex colinf has them horizontal. CJ also have them vertical. As did Dynaco.
Does it make a difference ? They are upside down usually in guitar amps....
941 posts |
