I need to buy a new set of tubes for my PV-5 but need some recommendations for specific tubes. Seeing that there were 4 5751's I'd found a matched quad on ebay but got the email below from the seller, so I need to learn more about what would represent a great set of tubes for this preamp. Any suggestions, or feedback on the below?
Email from tube seller:
"The way that tubes are utilized in the PV-5 are that the only tubes which are used as pairs are the 12AX7's. The two 12AX7's should be a matched pair of the same brand/make. All of the other tubes are used as singles which are running one side of the stereo left and one side right for each half of the tube. What that means is the we don't need to have 4 5751 all of the same make. We can customize the sound by using the right tube in the right position. Here are my recommendations.
V3-Raytheon windmill getter 5751 I have a single tube for $60. Best audio 5751 of all time.
V4-RCA triple mica longplate 5965. Early 1960's. Best of the 5965 $23
V5-1957 GE 5751 triple mica D-getter blackplate-All the 1950's GE blackplate are excellent quality but I like the 57 D-getter because they are sweeter sounding. I have a new one in box for $60
V6, V7 Sylvania two mica 5751 matched pair is $67.50 same as what you purchased.
V8 RCA triple mica 5965 same as V4 $23"
Email from tube seller:
"The way that tubes are utilized in the PV-5 are that the only tubes which are used as pairs are the 12AX7's. The two 12AX7's should be a matched pair of the same brand/make. All of the other tubes are used as singles which are running one side of the stereo left and one side right for each half of the tube. What that means is the we don't need to have 4 5751 all of the same make. We can customize the sound by using the right tube in the right position. Here are my recommendations.
V3-Raytheon windmill getter 5751 I have a single tube for $60. Best audio 5751 of all time.
V4-RCA triple mica longplate 5965. Early 1960's. Best of the 5965 $23
V5-1957 GE 5751 triple mica D-getter blackplate-All the 1950's GE blackplate are excellent quality but I like the 57 D-getter because they are sweeter sounding. I have a new one in box for $60
V6, V7 Sylvania two mica 5751 matched pair is $67.50 same as what you purchased.
V8 RCA triple mica 5965 same as V4 $23"
Antique Electric Supply has the 5965A for $3.65. V4 and V8 are cathode followers, there is no reason to pay more.
I would recommend that you contact Conrad Johnson for the 5751 as eBay seems to be a minefield of silly prices. I have bought two sets of tubes from cj for my PV5.
I would recommend that you contact Conrad Johnson for the 5751 as eBay seems to be a minefield of silly prices. I have bought two sets of tubes from cj for my PV5.
Thanks for the info, will make sure I don't spend a bundle on the 5965A's. Ed quoted me $425. plus shipping for a set of tubes so I'm hoping I can do better than that or I'll never hear this preamp🙂
(shakes head sadly)
As soon as they start putting vintage years and shapes of holes, and getter patterns on tubes, you know you've now entered the realm of stamp collecting.
ESRB has 5751WAs for $16 and 5965As for $3. You can ask them or AES about triple mica, long plates, but maybe not windmill getter?????? Noone has found a UFO getter yet?
I think that's ESRC not ESRB. If so, it's probably Stan who's a good man and I've bought loads of tubes from him at good prices. He's not averse to doing deals for a few tubes either. I don't recollect him testing any tubes but he no doubt has a tester. He mostly sells new in box tubes and quotes for new tubes.
Incidentally, how do you know you need new tubes - have you tested all the ones you have?
Incidentally, how do you know you need new tubes - have you tested all the ones you have?
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Honestly I don't know I need tubes, but the preamp never sounded very good since I got it, and I can't afford to have it rebuilt; Ed felt tubes were a good place to start. The set of tubes that came in it sound like a kind of mishmash but I don't really know, here's what's in it:
An externally hosted image should be here but it was not working when we last tested it.
Yep it is, I meant to leave a link.
Vacuum Tubes - Audio Tubes - ESRC Vacuum Tubes - Electron Tubes
Usually in older gear, pre 80s, capacitors are where to start. Film caps will start being leaky, and power supply caps will start drying up. Instead of spending that much on tubes, you might want to get them tested, although I probably would put the correct tubes in. The amplifier section of the preamp looks pretty simple. Everything except the phono goes through 4 tubes, a 5751 to amplifiy, 5965A cathode follower, another 5751 to amplify, and another 5965A cathode follower, for both channels. V5, V6, V7, and V8.
I guess the 12AT7s are inplace of the 5965As, since they are cathode followers, they'll work, but I dont know how the bias/sound will change.
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Funny I asked Ed about renewing the power supply caps and he said if they were a problem I'd hear a loud hum. I'll replace them myself if I can get a solid recommendation on what to put in there. It still has the original metal cans.
I kind of imagine if I have a good set of tubes and the p.s. caps are good, it should at least sound decent. Right now it's pretty muddy. I'm fine doing things like replacing caps etc. if I have trustworthy parts recommendations i.e. I don't want to be experimenting🙂
I'm just starting an updating of my son's Dynaco SCA-35 (with the Audioregenesis boards) and thought I'd get the CJ going at the same time to use with an ST-70 I updated some time ago to go with the CJ.
CJ wants $1450. for their teflon cap upgrade. Bill Thalman is now the more affordable option at something like $650 but still too rich for my blood and I really just would like to get this thing sounding like it's supposed to and see how I like it.
Much obliged for everyone's thoughts and information.
I kind of imagine if I have a good set of tubes and the p.s. caps are good, it should at least sound decent. Right now it's pretty muddy. I'm fine doing things like replacing caps etc. if I have trustworthy parts recommendations i.e. I don't want to be experimenting🙂
I'm just starting an updating of my son's Dynaco SCA-35 (with the Audioregenesis boards) and thought I'd get the CJ going at the same time to use with an ST-70 I updated some time ago to go with the CJ.
CJ wants $1450. for their teflon cap upgrade. Bill Thalman is now the more affordable option at something like $650 but still too rich for my blood and I really just would like to get this thing sounding like it's supposed to and see how I like it.
Much obliged for everyone's thoughts and information.
From CJ website:
V1 & V2: 12AX7
V3, V5, V6, & V7: 5751
V4 & V8: 5965
V1 & V2: 12AX7
V3, V5, V6, & V7: 5751
V4 & V8: 5965
An externally hosted image should be here but it was not working when we last tested it.
I have the 12AX7's covered, will pick up some inexpensive 5965's, leaving just the four 5751's to figure out. I'd ordered a matched quad from an ebay seller, nos Sylvania grey plates with disc getters but he sent me the comments noted in my first post...
So I guess my only question now is about the 5751's.
So I guess my only question now is about the 5751's.
Here's a post on a CJ PV-5. http://www.diyaudio.com/forums/tubes-valves/199266-cj-pv5-upgrades.html
Caps can make it sound muddy, along with poorly biased tubes, and maybe weak tubes. But usually weak tubes sound low and distorted. A low B+ can sound muddly, low, or distorted.
Caps, I'm not much on boutique high priced caps. I started with yellow film caps, moved up to solen (very fine caps for the price) and now use Russian PIO and orangedrops. $1 to $5 is enough for a cap for me. If it was a $7000 McIntosh, I might put in an Auricap or Hovland.
Look in Antique Electronic Supply LLC for a list of caps.
If you think you have a tube bad you can always swap between the 5751s and the 12AX7s. They are very close, with the 5751 being a militarized version of the 12AX7 with a little less gain 70 vs 100 and usually preferred between the 2.
Look at Sy's posts on the above link.
mmmalmberg said:
Caps can make it sound muddy, along with poorly biased tubes, and maybe weak tubes. But usually weak tubes sound low and distorted. A low B+ can sound muddly, low, or distorted.
Caps, I'm not much on boutique high priced caps. I started with yellow film caps, moved up to solen (very fine caps for the price) and now use Russian PIO and orangedrops. $1 to $5 is enough for a cap for me. If it was a $7000 McIntosh, I might put in an Auricap or Hovland.
Look in Antique Electronic Supply LLC for a list of caps.
If you think you have a tube bad you can always swap between the 5751s and the 12AX7s. They are very close, with the 5751 being a militarized version of the 12AX7 with a little less gain 70 vs 100 and usually preferred between the 2.
Look at Sy's posts on the above link.
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This was one of the threads, along with Ed's advice, that made me less anxious to mess with the caps other than updating the p.s. caps. If I could test caps and they measured close to their specified value, I guess I could figure they're not a problem, yes? I'm less anxious to recap the thing than retube it if I could determine the caps are somewhere near spec. My first choice would be to hear the intended sound of the preamp before doing anything to make it "better".
Seriously, forget all those stupid prices to recap, retube etc. They are way over market price. And get your advice here on these pages from those with no vested interest in selling you product.
If you want better coupling caps, get Russian FT-3 teflon caps. Cheap and available. If the voltage is 200v or under, use FT-2 because they're smaller. The smart money buys these Russian teflon caps - the most transparent (i.e. "not muddy") you'll find outside boutique stuff. And remember that the best cap is NO coupling cap, not some boutique nonsense. I doubt that replacing electrolytics will be audible, as long as they don't leak.
But take a look at what you have here. It's mainly a name - CJ. Strip that away and you have 2 things - a phono section (I believe...) and a line stage. The phono stage is OK and useful if you have vinyl. If you don't use vinyl, than there's absolutely no point in inserting this in your amplification chain. You probably don't need the gain - have you tried just a good stepped attenuator with discreet resistors and some way of switching inputs?
If you actually do need some gain, then build a really good preamp with a transformer output and a single tube, and use a great preamp tube like the 26, not a guitar tube like a 12AX7. No coupling caps and no high gain tubes you don't need. Probably the best build currently for a line stage is the "26 pre amp" thread. Tells you exactly how to build one. These preamps are SERIOUSLY world class. Your CJ isn't and never will be.
Andy
If you want better coupling caps, get Russian FT-3 teflon caps. Cheap and available. If the voltage is 200v or under, use FT-2 because they're smaller. The smart money buys these Russian teflon caps - the most transparent (i.e. "not muddy") you'll find outside boutique stuff. And remember that the best cap is NO coupling cap, not some boutique nonsense. I doubt that replacing electrolytics will be audible, as long as they don't leak.
But take a look at what you have here. It's mainly a name - CJ. Strip that away and you have 2 things - a phono section (I believe...) and a line stage. The phono stage is OK and useful if you have vinyl. If you don't use vinyl, than there's absolutely no point in inserting this in your amplification chain. You probably don't need the gain - have you tried just a good stepped attenuator with discreet resistors and some way of switching inputs?
If you actually do need some gain, then build a really good preamp with a transformer output and a single tube, and use a great preamp tube like the 26, not a guitar tube like a 12AX7. No coupling caps and no high gain tubes you don't need. Probably the best build currently for a line stage is the "26 pre amp" thread. Tells you exactly how to build one. These preamps are SERIOUSLY world class. Your CJ isn't and never will be.
Andy
There's a fair chance I'll be building another preamp as well for a second system. In the case of the cj, as I said I'm not particularly interested in changing the caps, and am primarily trying to find out whether the 5751's need to be matched and perhaps if anyone has specific recommendations for this tube. I don't have seriously world class ears but I do use vinyl and I am interested in hearing how this preamp is supposed to sound since I already own it🙂
Good points. I think CJ used polystyrene caps - these are the next best to teflon. If you have vinyl, then yes, an upgrade is worthwhile. It's a long time since I used 5751. I remember triple mica but that's all. I think mine were either GEC or Raytheon.
Only matching I see needed are the two sections of each tube, since each tube does left and right. Only the first 12AX7 in the phono (V1, and V2)section should be matched since V1 does left and V2 does right.
But still you need to find out why it sounds muddy. Hate to spend $400 and it still has a problem. I'd wait on caps and see how it sounds with the correct tubes in. With a tuner or CD as an input you only use V5, V6, V7, and V8.
Why would you need 4 tubes in a line stage? This in itself might be why the sound is veiled. You don't really need more than one low Rp tube and an output transformer in a line stage. High gain tubes and cathode followers is very old school, and then you have plate resistors, cathode bypass caps, coupling caps and all the rest of it.
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Then you might want to replace some of the 30 year old caps and also verify that the PSU is in proper working order -- all of the PV series was notorious for burning up the caps in the B+ circuit... as well as transformers and sometimes the pass transistors...
Don't start with tubes. Start with the PSU.
Remember, the audio circuits are nothing but a controlled oscillator for the DC from the PSU. If that DC is contaminated in some way you will never get the thing working correctly.
If you still really think that the tubes might be the problem, start swapping the tubes left to right and such. If the muddyness persists and doesn't move around you are most likely dealing with a problem other than burnt out tubes.
If you would like specific recommendations as how to procede PM me. 🙂
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