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Just me or are these RCA black plates pretty good?

StuartB

StuartB

AK Subscriber
Subscriber
I recently rebuilt a Dynaco SCA-35. I have been experimenting with different tubes...so far I am finding the RCA 7025 black plates, RCA black plate 6GH8A, and RCA black plate 6BQ5 tubes sound the best....just full, rich, balanced sound. Anyone else find these to be great sounding?
 
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Hiya,

Well if you know tube history like I do.

I think those were from the last gasp of the New Jersey Harrison Tube Plant ..

Or so the romantic in me likes to think.

Frannie
 
I use RCA black plate 12AT7s and 12AX7s in variety of amps. They are best I've found among many to-date. Shhh don't tell anybody!
 
Well, thanks to you I have a nice supply of black plate 6GH8A and 6U8A tubes for this SCA-35.

Thanks again, those black plates are rising to the top.
buglegirl said:
Hiya,

Well if you know tube history like I do.

I think those were from the last gasp of the New Jersey Harrison Tube Plant ..

Or so the romantic in me likes to think.

Frannie
Click to expand...
 
You are of course right.
They are great, and not over-the-top in price yet.
I have rolled about every 12AX7 through the phono section of my pre, and ended up with the black plates.
Transparent, great depth and sound stage.
 
IMO RCA 12AX7 black plates are the best all around 12AX7. The tube excels in preamp and tone control sections. Also very good in phono, the Brimar CV4004 has an edge as long as the RCA 12AX7 black plate is used downstream.
 
They are amazing

They are a tube that LIVE UP to their reputation. I have only found 1 pair better (for me) and that is the Sylvania Triple Mica Black plates 5751 (12AX7) with yellow gold lettering (not gold pin) ...and the only reason was for me, slightly more forward mids. Also so damn hard to find and be SURE they are authentic.

But when anyone asks, I tell them you can never go wrong with the RCA Blackplates. I just parted with a pair recently (I have more...lol) so I hope the buyer is loving em....
 
Different circuits sounds different with the same tube. So, it not possible to discredit anyone's experiences of declaring the best tube in their audio gear.

Using an upgraded Fisher 400, the RCA 12AX7 black plate was compared with two of us listening to a Sylvania 5751 black plate triple mica and GE 5751 black plate triple mica. Two tubes of same brand was placed in the input preamp and tone control section.

The RCA was best with more of an airy and open sound.
 
I use RCA 12AT7 blackplates in my preamp. They bested a pair of Telefunkens that previously resided there.
 
Very fond of the rca blackplate and the long black plate variant if available in several different tubes . (I wonder what the magic was?)
 
Very true...

sony6060 said:
Different circuits sounds different with the same tube. So, it not possible to discredit anyone's experiences of declaring the best tube in their audio gear.

Using an upgraded Fisher 400, the RCA 12AX7 black plate was compared with two of us listening to a Sylvania 5751 black plate triple mica and GE 5751 black plate triple mica. Two tubes of same brand was placed in the input preamp and tone control section.

The RCA was best with more of an airy and open sound.
Click to expand...

Every system has different synergy so I never say XYZ is THE perfect tube

My top 3
Sylvania 5751 Triple Mica Black plate
Mullard Blackburn plant circa 1960 12AX7
RCA Black Plate triple mica

each a little unique on my rig but all keepers. I switch out now and then for variety...I am trying to get another pair of the sylvania's as backup. will cost me $150 plus for a pair but I have to be sure they are the right ones...
 
I'm using RCA 6GH8's in my St 70 series 2, they sound very good. They are grey plates. I also have a pair of the black plates to try.
 
arcorob said:
Every system has different synergy so I never say XYZ is THE perfect tube

My top 3
Sylvania 5751 Triple Mica Black plate
Mullard Blackburn plant circa 1960 12AX7
RCA Black Plate triple mica

each a little unique on my rig but all keepers. I switch out now and then for variety...I am trying to get another pair of the sylvania's as backup. will cost me $150 plus for a pair but I have to be sure they are the right ones...
Click to expand...

Yes, my statement was for you. I find the RCA superior in the Fisher 400.
 
nj pheonix said:
Very fond of the rca blackplate and the long black plate variant if available in several different tubes . (I wonder what the magic was?)
Click to expand...

For starters, some say the early tubes were built on fresh tooling and are of precision tolerances inside that contributes to high quality sound.
 
arcorob said:
They are a tube that LIVE UP to their reputation. I have only found 1 pair better (for me) and that is the Sylvania Triple Mica Black plates 5751 (12AX7) with yellow gold lettering (not gold pin) ...and the only reason was for me, slightly more forward mids. Also so damn hard to find and be SURE they are authentic.

But when anyone asks, I tell them you can never go wrong with the RCA Blackplates. I just parted with a pair recently (I have more...lol) so I hope the buyer is loving em....
Click to expand...

You're gonna hate me, Rob. I picked up five Tektronix signal preamplifiers (for bench testing) from a salvage hut for $9/ea. and each preamplifier had two lab-matched low-noise black plate RCA 12AU7s and a triple-mica 5751. :banana:

So keep an eye out for old Tek preamplifiers as they're loaded with goodies.

-D
 
wow...I wouldnt know where to find them

derekva said:
You're gonna hate me, Rob. I picked up five Tektronix signal preamplifiers (for bench testing) from a salvage hut for $9/ea. and each preamplifier had two lab-matched low-noise black plate RCA 12AU7s and a triple-mica 5751. :banana:

So keep an eye out for old Tek preamplifiers as they're loaded with goodies.

-D
Click to expand...

I not only wouldn't know where ..I wouldn't know what they look like...LOL

Good score !
 
Just curious

sony6060 said:
Yes, my statement was for you. I find the RCA superior in the Fisher 400.
Click to expand...

Have you ever tried the Fisher branded Mullard's in your 400 ? I have two pair (one is the pair I mention in the prior post) ...Just curious...
 
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