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PREAMP TUBE GAIN CH...
 
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PREAMP TUBE GAIN CHART  

 

RavenDave
(@ravendave)
Founder of Raven Audio Admin
Joined: 2 years ago
Posts: 60
22/09/2019 10:40 am  

For those of you that have questions about the preamp tubes available and which to use in each row, and why you might not want to just use any tube anywhere.  Always ask me or another Raven Audio member about doing so before you try this, but I will start out with telling you that you can easily swap a 12AU7, and any of its equivalents: 12BH7, 5963, 5814 or 6189 - into any of the three preamp rows on any of the current Avian Series amplifiers.

For nearfield listening (systems which are desktop, and you are listening to the speakers within 4 to 6 feet of your ears) you may want to do exactly that.  But for the rest of you that listen with an equilateral triangle setup (where the listener is 8 to 10 feet from the speakers) you should keep with the current suggested tube layout chart where there is a 12AT7 or equal in row 1, a 12AT7 or equal in row 2 and 12AU7 in row 3.  But here is where it absolutely can get interesting.

Since there are other choices with slightly lower gains, you can experiment with the other tubes on this list.  If you have a question about preamp tubes, you can ALWAYS  call me, any day any time.  Just remember I am in Texas.  My number is: 936-662-5100.  The only real rule is: NEVER USE A 12AX7 TUBE in any row.   The gain is far too high for this amplifier's design.  It will overdrive the preamp section going into the power amp and cause distortion.  The rest are pretty much fair game though, so have fun~!

Remember also that I have literally thousands of preamp, and some power tubes that are available to ONLY RavenHeads.  So talk with me if you want to try out the domestic, European or even more exotic.  Chances are...   I have some in stock for you.

TUBE GAIN CHART & SUBSTITUTIONS

*12AX7 - 100 - DO NOT USE IN AVIAN SERIES AMPLIFIERS PLEASE! - Call RavenDave if you want to talk about this.  There are rare exceptions.
12AT7 - 60 
12AY7 - 45
12AV7 - 42
12AU7 - 19

Other substitutes in these families are (some are much more resilient and built for rugged use, called "ruggedized" in the tube field):
12AX7 - ECC83, 7025, ECC803, E83CC, 6681 (YOU SHOULD NOT USE THIS TUBE IN A RAVEN AUDIO AVIAN SERIES INTEGRATED!)*
12AT7 - ECC81, 6201, 6679, 6060
12AY7 - 6072
12AV7 - 5965
12AU7 - ECC82, 5963, 5814, 6189

Some of these equivalents can be much quieter, built for piston engine aircraft or field radio use, so they can be well worth a try.

*As I mentioned above...  you should NEVER use a 12AX7 in any Raven Audio preamp section - BUT there may be a very few exceptions.  Call me first~!!!

Again, if you have questions, please just call me~!

RavenDave


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Scotty
(@scotty)
Active Member
Joined: 2 months ago
Posts: 11
27/06/2020 6:26 pm  

Well, being an adventurous sort of guy, and since I have a nearfield listening environment (see RavenDave's Dozen for a photo of my studio / study setup) - I thought I would try experimenting with all AU7 types in Rows 1,2,3 per Dave's thoughts above. My speakers, in this setup, are approximately 3'-0" from the ears.

For Row 1, I rolled in a pair of Mullard CV4003 (6189) (early 1980's) - known for resistance to microphonics, deep expansive soundstage with definition, liquid smooth highs, leans to the warm side of neutral.

For Row 2, I plugged in CBS Hytron 5814WA's (nice 1950's)

For Row 3, I left in the excellent RCA 12AU7 Black Plates (RavenDave No 26 in his RavenDave Dozen list)

As Dave points out above, the gain for the 12AU7 is less than the 12AT7 (19 vs 60), and I noted that the volume knob for my normal listening level changed from 8:30 (AT7) to 9:00 (AU7)..........very insignificant really.

My listening impressions are lush, sweet, mellow, rich, relaxed, holographic, the female soprano voices are incredibly sweet, not sibilant. The presentation was not quite as exciting as the AT7 version, but is very enjoyable. I think I will leave it this way for a week or so.

For the listening trial: Female voices: Alison Kraus, Norah Jones, Rebecca Pidgeon, Enya, Diana Krall, Sara McLachlan, Eva Cassidy, Fleetwood Mac. Male voices: Alan Jackson, JJ Cale, Jack Johnson, Jeff Buckley, John Mayer, Leonard Cohen, Mark Knopfler, Paul Simon.


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Greg
 Greg
(@mrgrey)
Eminent Member
Joined: 9 months ago
Posts: 22
27/06/2020 10:55 pm  

@scotty

Turns out you are a man after my own heart Scotty. Virtually all the female vocalists and half the males are some of my favorites as well. Am not familiar with Rebecca Pidgeon, Jeff Buckley and Leonard Cohen. A couple of females not listed that I really like are Ruth Moody and Kim Richey. I have enough 12AU7’s to try them in all 3 rows so may have to give that a whirl sometime myself. Thanks for sharing. 


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RavenDave
(@ravendave)
Founder of Raven Audio Admin
Joined: 2 years ago
Posts: 60
27/06/2020 11:58 pm  

@scotty  You had better add the George Jones album "Who's Gonna Fill Their Shoes" and "Hits I Missed and One I Didn't" and Vern Gosdin's "Chiseled in Stone" to that list.  Both are engineering and production marvels from those days.  Today's albums cannot touch them.  Of course...   Billy Sherrill produced them is why!  Then get any Linda Ronstadt album with Nelson Riddle, or her two Spanish language albums - "Conciones de Mi Padre" and "Mas Conciones"  She sang all these songs for her father - and you can tell it in ever single word.  The production on all of her non-pop albums is also breathtaking and the musicianship and performance is absolutely splendid.


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Scotty
(@scotty)
Active Member
Joined: 2 months ago
Posts: 11
28/06/2020 9:34 am  

Greg, thanks for your feedback - 

Rebecca Pidgeon is an actress, songwriter, and singer - she is most famous for her version of Spanish Harlem. I have her album Slingshot, which has some nice stuff: Slingshot, Sweet Hand of Mercy, Disintegration Man, Tremble, Kiss Me, Baby Please come home again. Jeff Buckley was the original recorder of Hallelujah (best of my knowledge). Leonard Cohen has the most deep, gravely voice I have ever heard - try his album Old Ideas: songs Lullaby and Going Home.

Dave, not only are you a tube guru, you know your vintage music - you probably sang with those guys, lol.

Thanks for the heads up on George Jones and Vern Gosdin albums; will definitely pick those up. I forgot to mention Linda Ronstadt - her song Blue Train gets lots of repeats - and I wlll also pick up her Spanish albums you mention - her history with the Eagles is very interesting. She is incredible.

I forgot to mention other favorite artists - they just weren't involved in my tube rolling experiment: Shelby Lynne, Sam Cooke, Sissel, Rosanne Cash, Willie Nelson, Yo-Yo Ma, Jennifer Warnes, Roy Orbison (try his Black & White Night bluray), Sade, Michael Buble (try his bluray Caught in the Act), Johnny Rivers, Jim Croce, James Taylor, Eagles, Dire Straits, Cat Stevens.

Like Dave implies, well recorded music is in the minority in my experience (maybe 10% of albums have the dynamics and richness I am looking for). Mark Knopfler is a good example; all of his stuff is well produced.

Thanks my fellow Ravenmaniacs..........


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Greg
 Greg
(@mrgrey)
Eminent Member
Joined: 9 months ago
Posts: 22
28/06/2020 6:53 pm  

Thanks Scotty. Always fun to try different artists. Couldn’t agree more on recordings. Most of the others you mentioned I know of, though I have only spent significant time with Sade, Shelby Lynne, Rosanne Cash, Eagles, Dire Straits (amazing recordings) and Cat Stevens. I also really like Ray Bonneville, Ray LaMontagne (his early stuff), Amos Lee and Gretchen Peters. Unlikely as it may seem given my taste in music one of the best albums I have is Rock Steady by No Doubt. Just need to buckle your seatbelt for that one but the recordings are really magical with their dynamics and soundstage. I look forward to trying your recommendations. I use Roon with TIDAL so it is pretty easy to track down music. 

Greg

 


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Greg
 Greg
(@mrgrey)
Eminent Member
Joined: 9 months ago
Posts: 22
01/07/2020 2:54 pm  

Hey Scotty

I was wondering if you, or anyone else reading this for that matter, have heard of Brandi Shearer? She only has two albums, both of which I love. I like her voice and personality that comes through her music, and they are good recordings. Unfortunately it seems she has moved on to other things because I can’t find anything about her since around 2012. 


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Scotty
(@scotty)
Active Member
Joined: 2 months ago
Posts: 11
01/07/2020 7:14 pm  

@mrgrey -

I haven't been familiar with Brandi's music, I checked out some of her stuff tonight at Amazon - she has a nice, sultry sound - will try more..........thanks. We should probably start a thread - What are you listening to tonight? - 


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RavenDave
(@ravendave)
Founder of Raven Audio Admin
Joined: 2 years ago
Posts: 60
01/07/2020 9:34 pm  

PLEASE DO GUYS~!!!  That would be awesome.   We are WAY off topic here and I worry nobody will find these great suggestions.

 

And...   add Dave's True Story to your lists...   great band, excellent recordings... but of course that's true, they are on Chesky Records.


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Greg
 Greg
(@mrgrey)
Eminent Member
Joined: 9 months ago
Posts: 22
02/07/2020 3:40 pm  

I apologize Dave. I wanted to do a private convo but per Bryant the forum is not set up for that. Didn’t even think about which forum we were in - my bad on that. For future reference which of the forums should one utilize for that kind of thing? If there is a way to delete posts I would be glad to do that. 
Greg


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