Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Voxbox on October 22, 2013, 04:00:09 pm
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Hi All,
Following my experiences earlier this year with a 66 PRO REVERB, I found I really liked the sound of the original Sylvania 7025s over anything else I tried as they just seem more musical.
I've now got a great condition Brown Vibrasonic from the early 60s in for checking over. There are a couple of RCA 7025s still in it, but I'd like to get my hands on some Sylvanias to replace the remaining pre-amp valves that have been changed for other brands (like Peavey), but they are eluding me!
So what would folks recommend as a replacement if I cant get the Sylvanias?
For the 6L6GCs I'm going to use Winged Cs. Any other suggestions?
One other thing is that the valve chart shows a 12AX7 as the PI, but the schematic shows a 7025. The 7025 is an improved version of the 12AX7 so I'm not sure why the chart and the schematic are different. Guess it doesnt really matter for the PI position?
thanks for your help
Cheers, Voxbox
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As you say, the 7025 is a "better" 12AX7. Any good tube-dealer of the day would know they are the same tube, except fussy customers might pay more for 7025. Maybe Fender didn't want to commit to 7025 on the chart, but if they got 7025 for a good price, they threw them in.
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Voxbox, www.hitestguitars.com (http://www.hitestguitars.com) lists NOS Sylvania 7025s in stock. I have bought from him (Gregg Levy) before several times and his stuff is the real deal NOS NIB, no "ANOS in white box" masquerading as NOS.
Please tell us what you like about them, as they are half the price of the RCA long black plate 7025, which I have one of that I got from Hitest and like a lot.
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Foghornleghorn,
The best answer I can give is that the Sylvania's sound more musical than anything else I tried - GE 5751 NOS cryogenically treated, TungSol 12AX7, JJ's, but no RCAs unfortunately.
Really hard to define…..
Sorry I can't be more helpful!
Cheers
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hi
these tubes can be bought and a what up inside ...sometimes they are already sold .
7025/12AX7 $15.00 Zenith 115%/115% 1250:1200/1250Gm used (wb) (M9) square gray plates - top halo getter - special 12AX7
1 7025/12AX7 $15.00 Fender 100%/100% 1250:1200/1250Gm used (wb) (M9) square gray plates - top halo getter - special 12AX7
tom
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Thanks for you replies guys
Errrr..... What's a "what up inside"? I can speak Americano, but can someone translate into Lowland Scots for me please?
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hi
my keyboard is dirty and I do a lot of retyping the missing letters ..
here is something to think about ..
1 5751/12AX7 $25.00 GE 120%/120% 1250:1250/1250Gm NOS (ob) (M9) JAN gray plates - green lettering - double stuff mica - halo getter
1 5751/12AX7 $25.00 Sylvania 120%/140% 1250:1350/1250Gm NOS (ob) (M9) JAN square gray plates - green lettering - halo getter
1 5751/12AX7/CV4017 $25.00 Philips 120%/120% 1450:1450/1250Gm NOS (OB) (M9) USA - square gray plates - top getter
1 6681/12AX7 $25.00 GE 100%/110% 1400:1400/1250Gm NOS (OB) (M9) square black plates - red lettering - top getter
1 6681/12AX7 $25.00 GE 100%/110% 1200:1250/1250Gm NOS (OB) (M9) rectangular ribbed gray plates - white lettering - top getter
1 6681/12AX7 $25.00 GE 120%/140% 1300:1500/1250Gm NOS (OB) (M9) rectangular ribbed gray plates - white lettering - top getter
1 7025/12AX7WA $25.00 Sovtek 120%/130% 1350:1400/1250Gm NOS (wb) (M9) short gray plates - tripple mica
1 7025/12AX7WA $25.00 Sovtek 140%/145% 1350:1500/1250Gm NOS (wb) (M9) short gray plates - tripple mica
1 7025A/12AX7A $25.00 NEC 140%/140% 1400:1650/1250Gm NOS (wb) (M9) gray plates - Japan
1 7025/12AX7 $15.00 Zenith 115%/115% 1250:1200/1250Gm used (wb) (M9) square gray plates - top halo getter - special 12AX7
1 7025/12AX7 $15.00 Fender 100%/100% 1250:1200/1250Gm used (wb) (M9) square gray plates - top halo getter - special 12AX7
1 7025/12AX7WB $5.00 Sovtek 90%/100% 900:1000/1250Gm used (L) (M9) short gray plates