Preamp Tubes? - Who, What, When, Where, Why, and How? - Page 63

solarburnDSL50 · 10-29-2009, 05:31 AM

Quote:

Originally Posted by ken361

Im open for suggestions on my JVM for the v1. So far the RFT is the best, didnt care much for the tele's, seemed to the blanket effect(kinda muffled) good crunch but not eq'd great. I have a GE jan, they just dont seem to clear sounding to me. The jvm is a bright sounding amp so the RFT works well, then I have some chinese down the line. Hoping mullard or something else will bring this amp up more. I like old school rock and metal.

I'd try a Mullard. I mean if all you are looking for is to try it in V1 that means you only have to get 1 tube. So money wise the experiment won't cost you a bunch having to replace them all. Have you tried a Raytheon BP yet? If you like the character of the RFT you may like what the BP offers too.

If it was me I'd try the Mullard and the BP to see what I'd get. I also recommend the Jan Philips 12AX7WA. Great upper mids without being bright or harsh. I seem to always put 1 in my mix either in V1 or V2 where I have it now.

Speculating always kept me guessing. To truly know you have to put the tube in. You could just get 1 for now and then try another down the road. That's how I do it now. The other slots are filled on mine and I don't need to roll them anymore so picking 1 up here and there is easy on the wallet.

What power tubes are in your JVM? I think power tubes can have a noticeable EQ effect as well. So you could tailor the tone for more lowend, ballzier mids maybe even low mids and then smoother in the high end and not icepicky. I know a couple different power tubes that worked like this in my DSL one set of which I'm using.

MartyStrat54 · 10-29-2009, 01:43 PM

Quote:

Originally Posted by ken361

Im open for suggestions on my JVM for the v1. So far the RFT is the best, didnt care much for the tele's, seemed to the blanket effect(kinda muffled) good crunch but not eq'd great. I have a GE jan, they just dont seem to clear sounding to me. The jvm is a bright sounding amp so the RFT works well, then I have some chinese down the line. Hoping mullard or something else will bring this amp up more. I like old school rock and metal.

If you have Tele's that are muffled, then there is something wrong with the tube. One side of one of the tubes could have gave out. Remember, a 12AX7 tubes has two triodes and if one side goes out, the tube will still work, but sound like crap. On my tester I have had tubes show 27 on triode one and 11 on triode two. Not a good tube for a guitar.

Another tube that is probably my favorite is an Amperex tube. You can get a relabeled Amperex for around $25 to $35 dollars on EBAY. These tubes are very sweet sounding throughout the audio frequency range. I especially like the top end of an Amperex, very smooth. This will take the shrill out of a bright amp.

Another tube that smooths out a bright amp is a Raytheon or RCA Black Plate (preferably a pre-1966 tube). This or a 1959 RCA short, gray plate tube. It is very close to the Amperex in sound quality.

The trick of course with any of these tubes is to find one's with the proper gain level. Usually I do not go nuts with the gain on V1 unless I only play tap and shredder styles. I usually go with a medium to hot medium tube for V1. I then put a high gain in V2.

Also, not to be critical. If you have high quality NOS tubes in all slots that's great. Personally, I only use the high dollar one's in V1 and V2. I have Sylvania Gray Plates in V3 and V4. The Sylvania's are very good tubes. In fact they were picked over RCA for many years until the mid 50's. The thing is there are so many of them. So I go with what I know works in V3 and V4 without having to waste the Tele's, Mullards or Amperex's.

I about left this out. The GE JAN. Yes, I have written about this before. Some of the early JAN tubes seem to sound good. However, the newer one's were constructed for high shock applications. The internal parts are beefy and this causes the cardboard sound. I issued a statement here on the tube thread that the JAN and WA style tubes may not have a good sound to them. They are pumped up on EBAY as something exotic, when the fact is they are gov't tubes made for non-guitar amp applications.

ken361 · 10-29-2009, 02:01 PM

Quote:

Originally Posted by solarburnDSL50

I'd try a Mullard. I mean if all you are looking for is to try it in V1 that means you only have to get 1 tube. So money wise the experiment won't cost you a bunch having to replace them all. Have you tried a Raytheon BP yet? If you like the character of the RFT you may like what the BP offers too.

If it was me I'd try the Mullard and the BP to see what I'd get. I also recommend the Jan Philips 12AX7WA. Great upper mids without being bright or harsh. I seem to always put 1 in my mix either in V1 or V2 where I have it now.

Speculating always kept me guessing. To truly know you have to put the tube in. You could just get 1 for now and then try another down the road. That's how I do it now. The other slots are filled on mine and I don't need to roll them anymore so picking 1 up here and there is easy on the wallet.

What power tubes are in your JVM? I think power tubes can have a noticeable EQ effect as well. So you could tailor the tone for more lowend, ballzier mids maybe even low mids and then smoother in the high end and not icepicky. I know a couple different power tubes that worked like this in my DSL one set of which I'm using.

winged C's 2 power tubes

ken361 · 10-29-2009, 02:03 PM

Quote:

Originally Posted by MartyStrat54

If you have Tele's that are muffled, then there is something wrong with the tube. One side of one of the tubes could have gave out. Remember, a 12AX7 tubes has two triodes and if one side goes out, the tube will still work, but sound like crap. On my tester I have had tubes show 27 on triode one and 11 on triode two. Not a good tube for a guitar.

Another tube that is probably my favorite is an Amperex tube. You can get a relabeled Amperex for around $25 to $35 dollars on EBAY. These tubes are very sweet sounding throughout the audio frequency range. I especially like the top end of an Amperex, very smooth. This will take the shrill out of a bright amp.

Another tube that smooths out a bright amp is a Raytheon or RCA Black Plate (preferably a pre-1966 tube). This or a 1959 RCA short, gray plate tube. It is very close to the Amperex in sound quality.

The trick of course with any of these tubes is to find one's with the proper gain level. Usually I do not go nuts with the gain on V1 unless I only play tap and shredder styles. I usually go with a medium to hot medium tube for V1. I then put a high gain in V2.

Also, not to be critical. If you have high quality NOS tubes in all slots that's great. Personally, I only use the high dollar one's in V1 and V2. I have Sylvania Gray Plates in V3 and V4. The Sylvania's are very good tubes. In fact they were picked over RCA for many years until the mid 50's. The thing is there are so many of them. So I go with what I know works in V3 and V4 without having to waste the Tele's, Mullards or Amperex's.

I about left this out. The GE JAN. Yes, I have written about this before. Some of the early JAN tubes seem to sound good. However, the newer one's were constructed for high shock applications. The internal parts are beefy and this causes the cardboard sound. I issued a statement here on the tube thread that the JAN and WA style tubes may not have a good sound to them. They are pumped up on EBAY as something exotic, when the fact is they are gov't tubes made for non-guitar amp applications.

marty what do you have in your stash? keep the rft in v1? then get something else?

MartyStrat54 · 10-29-2009, 07:10 PM

I think the RFT in V1 is a keeper. However, we don't know how it tests. My prior experience with these tubes is they can be on the stout side. Just to fill you in, I use a calibrated B and K 707 with solid state rectification. It measures 12AX7's in the following manner. 22-22 represents a nominal new tube. Again, my experience is that 22 represents like 80 per cent. However, just going up eight points, you are now in high gain country. So, a 30-30 would be a smoking tube for V2. Usually, we run a 24-24 in V1 matched up to the high gainer. Also of note: A 35-35 tube is too much gain for either V1 or V2. You can use a high gain tube like this in V3 or V4. (Some people have tried extra high gain tubes in V1 and V2. Some amps work okay and others do not.)

Also, to catch you up, we all were using a 7025 in V1. This is an extra quiet 12AX7 style tube (a 6681 is another). This was great for a nice clean channel and then the high gainer in V2 would allow you to get the crunch you needed. However, over the past three months, we have all been trying different tubes in V1. V1 is your flavor tube. The sound and tone of this tube will be amplified by the V2 tube. Only a little of the flavor of V2 will be included in the amplified signal. The 7025 is a quiet tube, but it doesn't have the flavor of some of these high end NOS tubes. It's all about what you like to hear coming out of your amp.

What does this mean? It means that most of us have taken the 7025's out of our amps and we are using Mullards, Telefunkens, RFT's, and Amperex tubes in V1. Right now, a lot of the guys here are hot on the smooth plate Telefunken. My favorite is still a Philips/Amperex tube of around 26-26 in V1 and a 29-29 in V2. Keep in mind that the tubes are not perfect. Some will test out at 25-26 and others will test at 24-28. The trick is that if you use the 24-28 tube, the "28" will be the side that feeds into V2 so you will get more gain over the 25-26. You follow me?

Now, about you. You have a V1 and you are looking for a V2. Do you want a 28-28, or do you want the 30-30? How much gain and OD and distortion are you wanting out of your amp? Do you want a tube that will help smooth the top end? Do you feel that your RFT is not contributing to a shrill top end. The RFT's are like a more gritty Mullard. They are great tubes if you are looking for earlier tube breakup. I will take a look at some tubes that I have and see what the test scores are. I will send you a PM with pricing.

MartyStrat54 · 10-29-2009, 07:19 PM

Quote:

Originally Posted by solarburnDSL50

If it was me I'd try the Mullard and the BP to see what I'd get. I also recommend the Jan Philips 12AX7WA. Great upper mids without being bright or harsh. I seem to always put 1 in my mix either in V1 or V2 where I have it now.

Joe, I don't know what year of JAN tubes you have tried and liked? There are some that do sound good, but these tend to be the earlier 12AX7A's. I posted here to Ken and also on this thread a while back about JAN and WA tubes (they can be either a JAN a JAN WA or a WA). The later versions just do not sound good due to internal construction.

You may have some older one's. I do. In fact I think I have about 18 to 20 RCA WA's, but they are older tubes. Anyway, I did want to clarify to you about this as I came across some in depth material several months ago and passed it on via the thread.

ken361 · 10-29-2009, 07:36 PM

Quote:

Originally Posted by MartyStrat54

I think the RFT in V1 is a keeper. However, we don't know how it tests. My prior experience with these tubes is they can be on the stout side. Just to fill you in, I use a calibrated B and K 707 with solid state rectification. It measures 12AX7's in the following manner. 22-22 represents a nominal new tube. Again, my experience is that 22 represents like 80 per cent. However, just going up eight points, you are now in high gain country. So, a 30-30 would be a smoking tube for V2. Usually, we run a 24-24 in V1 matched up to the high gainer. Also of note: A 35-35 tube is too much gain for either V1 or V2. You can use a high gain tube like this in V3 or V4. (Some people have tried extra high gain tubes in V1 and V2. Some amps work okay and others do not.)

Also, to catch you up, we all were using a 7025 in V1. This is an extra quiet 12AX7 style tube (a 6681 is another). This was great for a nice clean channel and then the high gainer in V2 would allow you to get the crunch you needed. However, over the past three months, we have all been trying different tubes in V1. V1 is your flavor tube. The sound and tone of this tube will be amplified by the V2 tube. Only a little of the flavor of V2 will be included in the amplified signal. The 7025 is a quiet tube, but it doesn't have the flavor of some of these high end NOS tubes. It's all about what you like to hear coming out of your amp.

What does this mean? It means that most of us have taken the 7025 out of our amps and we are using Mullards, Telefunkens, RFT's, and Amperex tubes in V1. Right now, a lot of the guys here are hot on the smooth plate Telefunken. My favorite is still a Philips/Amperex tube of around 26-26 in V1 and a 29-29 in V2. Keep in mind that the tubes are not perfect. Some will test out at 25-26 and others will test at 24-28. The trick is that if you use the 24-28 tube, the "28" will be the side that feeds into V2 so you will get more gain over the 25-26. You follow me?

Now, about you. You have a V1 and you are looking for a V2. Do you want a 28-28, or do you want the 30-30? How much gain and OD and distortion are you wanting out of your amp? Do you want a tube that will help smooth the top end? Do you feel that your RFT is not contributing to a shrill top end. The RFT's are like a more gritty Mullard. They are great tubes were you are looking for earlier tube breakup. I will take a look at some tubes that I have and see what the test scores are. I will send you a PM with pricing.

well i like a thick good distortion, kinda 80's 90's metal a clean distortion not muddy of blanket type sounding tube. Mine sounds pretty good but i think v2 needs a good tube because theres a chinese in there. Mullard or amperex go nice wth the rft? Thanks!!

ken361 · 10-29-2009, 07:38 PM

30/30 in V2 prob, be good huh?

solarburnDSL50 · 10-29-2009, 08:04 PM

Quote:

Originally Posted by MartyStrat54

Joe, I don't know what year of JAN tubes you have tried and liked? There are some that do sound good, but these tend to be the earlier 12AX7A's. I posted here to Ken and also on this thread a while back about JAN and WA tubes (they can be either a JAN a JAN WA or a WA). The later versions just do not sound good due to internal construction.

You may have some older one's. I do. In fact I think I have about 18 to 20 RCA WA's, but they are older tubes. Anyway, I did want to clarify to you about this as I came across some in depth material several months ago and passed it on via the thread.

I'm just look'n foolish tonight hahahaha! Well it looks like I got a couple of the bad ones...From Doug's is where I got them:

JAN Philips 12AX7WA

The last of the 80's military production, has a nice creamy sound when overdriven. Highly recommended, every guitar player should have one.

I actually like them though. I have one in the NT along with an RFT. The DSL has the RFT(V1)and the JP(V2). Tone wise I put them right up there with my other favs Mullard, RFT and BP but I'm only getting the flavor of 1 in the mix. Maybe more than one in the preamp causes problems. I like how their mids mix with other tubes.

Now I feel like my ears are no good...

I take it you've probably tried them and hated it?

Maybe I shouldn't mention the JPs anymore so's I don't influence someone to buy a questionable NOS tube.

That's alot of money for one.

Led Hendriani · 10-29-2009, 08:05 PM

Any one know if I can use a 5687 as an exact replacement for a 12AX7 without having to modify anything?
Thanks!

ken361 · 10-29-2009, 08:13 PM

Quote:

Originally Posted by solarburnDSL50

I'm just look'n foolish tonight hahahaha! Well it looks like I got a couple of the bad ones...From Doug's is where I got them:

JAN Philips 12AX7WA

The last of the 80's military production, has a nice creamy sound when overdriven. Highly recommended, every guitar player should have one.

I actually like them though. I have one in the NT along with an RFT. The DSL has the RFT(V1)and the JP(V2). Tone wise I put them right up there with my other favs Mullard, RFT and BP but I'm only getting the flavor of 1 in the mix. Maybe more than one in the preamp causes problems. I like how their mids mix with other tubes.

Now I feel like my ears are no good...

I take it you've probably tried them and hated it?

Maybe I shouldn't mention the JPs anymore so's I don't influence someone to buy a questionable NOS tube.

That's alot of money for one.

I have one too lol, I liked it in one of older combo amp but it made too much noise in the v1 and i didn't care for it too much in the marshall. some of the old tubes just sound muddy not clear you know! like marty says you have the gains in the right sections of v1 and v2 i guess

solarburnDSL50 · 10-29-2009, 08:17 PM

Quote:

Originally Posted by ken361

I have one too lol, I liked it in one of older combo amp but it made too much noise in the v1 and i didn't care for it too much in the marshall. some of the old tubes just sound muddy not clear you know! like marty says you have the gains in the right sections of v1 and v2 i guess

I actually find it clear and articulate. I even put it in my HT Dual and it improved the tone there I thought.

I don't know what to say guyz...

I will qualify that I like those other tubes too so my ears can't be total failure.

ken361 · 10-29-2009, 08:26 PM

Quote:

Originally Posted by solarburnDSL50

I actually find it clear and articulate. I even put it in my HT Dual and it improved the tone there I thought.

I don't know what to say guyz...

I will qualify that I like those other tubes too so my ears can't be total failure.

you probley have a good one! when you buy used you never know what you get, could always send it back lol. I think some tubes work well in some amps and not in others.

MartyStrat54 · 10-29-2009, 08:34 PM

Quote:

Originally Posted by Led Hendriani

Any one know if I can use a 5687 as an exact replacement for a 12AX7 without having to modify anything?
Thanks!

This tube has a different pin out than a 12AX7 (9A pin out). The 5687 (9H pin out), although a very stout tube voltage wise, only has an amplification factor of 17.5, or about what a 12AU7 has. This will neuter your sound.

What are you trying to accomplish? Maybe one of the guys can give you some advice.

solarburnDSL50 · 10-29-2009, 08:35 PM

Quote:

Originally Posted by ken361

you probley have a good one! when you buy used you never know what you get, could always send it back lol. I think some tubes work well in some amps and not in others.

I appreciate it ken. Will call it an anomaly. That should cover the 2 that I think rock hehe.

Now on with the Mullards, BP's, RCA's, RFT's, Tele's etc...

MartyStrat54 · 10-29-2009, 08:38 PM

More Telefunken Smooth Plate versus Telefunken by RFT Smooth Plate. Hey they both sound great!

Real one on the left, East German model on the right. Funny, the real Tele doesn't say, "Made in W. Germany," but the RFT (E. Germany) says West Germany on the tube. Watch me put this peanut under one of these three cups. Now watch closely and tell me which cup the nut is under.

RiverRatt · 10-29-2009, 08:44 PM

Quote:

Originally Posted by Led Hendriani

Any one know if I can use a 5687 as an exact replacement for a 12AX7 without having to modify anything?
Thanks!

No, the pinout is different.

EDIT: Sorry for the redundant post - these guys are fast.

MartyStrat54 · 10-29-2009, 08:54 PM

Now a tube that I would like any information on. A Raytheon "Registered" tube. Has a tight mounted, slant D getter (Note skewed getter flash on tube.) Has the number 122 printed on the tube. Raytheon's EIA Code is 280, so this is some kind of lot number. The only other number on the tube is, "7025."

The plate looks more like a European rib design. Normal Raytheon plates are flat on the ends and then there is a small raised area in the middle with the raised area sticking outwards. This plate is not like that. It is wide.

How about it Alan. Any suggestions? Did Raytheon make a Slant D Getter? This is the only Raytheon Registered tube that I have and the only one I've seen.

solarburnDSL50 · 10-29-2009, 08:55 PM

Ooooh! Tube porn!

I'm ready for mine on November 10th. I must try the TeleFunken.

You still have it tucked away right........?

MartyStrat54 · 10-29-2009, 09:02 PM

In reference to the JAN and WA tubes...a while back Joe and I were amazed at this tube. It is the Holy Grail of JAN tubes. Made by Raytheon. This tube was packed on 8/63. Dark Gray Plate style tube, 12AX7. Tests 30-31. The price for one of these is $200. I got two of them on EBAY for $55. One reads lower at 26-24.

1963...it was a very good year!

Stenciled at the top inside of the box is "ARDM."

RiverRatt · 10-29-2009, 09:08 PM

I've looked at a lot of D-getter tubes trying to find a match for the Sonotone clear tops. Am I seeing seams on top?? It looks like an Amperex. I'm looking through the tubemonger stuff to see if I can find that picture again.

MartyStrat54 · 10-29-2009, 09:11 PM

Quote:

Originally Posted by solarburnDSL50

Ooooh! Tube porn!

I'm ready for mine on November 10th. I must try the TeleFunken.

You still have it tucked away right........?

I've sold all the Tele's except for one smooth plate that tests 11-14. I wanted to save one with a lot of snap left in it. Sounds good, doesn't it? 11-14?

Joe, I have a boatload of Tele's, just waiting to hear from you. Smooth, ribbed (like a special Trojan) or RFT Smooth Plates. Maybe you should try one of each? You might end up with the RFT/Tele. They seem to be a little more aggressive. How does that sound? One of each and you can send the two back you don't like. Or would that be the one back that you don't like, or would that be I'm keeping all three?

Didn't you want a hot medium like a 26-26, or do you want like a 24-24?

solarburnDSL50 · 10-29-2009, 09:18 PM

Quote:

Originally Posted by MartyStrat54

I've sold all the Tele's except for one smooth plate that tests 11-14. I wanted to save one with a lot of snap left in it. Sounds good, doesn't it? 11-14?

Joe, I have a boatload of Tele's, just waiting to hear from you. Smooth, ribbed (like a special Trojan) or RFT Smooth Plates. Maybe you should try one of each? You might end up with the RFT/Tele. They seem to be a little more aggressive. How does that sound? One of each and you can send the two back you don't like. Or would that be the one back that you don't like, or would that be I'm keeping all three?

Didn't you want a hot medium like a 26-26, or do you want like a 24-24?

I think I'll need to try both. The 24-24 and the 26-26. I think I better try an RFT version along with a Tele. Wait there are 3 versions due to one being ribbed too. Yep better send all 3 options and then I'll pick 1...most likely.

solarburnDSL50 · 10-29-2009, 09:28 PM

Well guyz I have to go watch a scary movie with me daughter so I'll be away for awhile.

Marty don't be selling those tubes while I'm gone...

And don't be talk'n about how I like bad tone cause I use sucky tubes either!

Later dudes.

RiverRatt · 10-29-2009, 09:29 PM

I think these are the ones I was thinking about.

MartyStrat54 · 10-29-2009, 09:31 PM

Quote:

Originally Posted by RiverRatt

I've looked at a lot of D-getter tubes trying to find a match for the Sonotone clear tops. Am I seeing seams on top?? It looks like an Amperex. I'm looking through the tubemonger stuff to see if I can find that picture again.

Pardon me for a moment while I take this boot to my ass. Yes, it is the pinch top on the tube. I forgot to put it down when posting. It has the type of pinch that you would see on an Amperex versus a Mullard. The Amperex pinch top is usually put together with tighter tolerances.

So we have the pinch top, the Euro style plates. Maybe Raytheon had Amperex do a run of slant tops for them. It's definitely a well built, high quality tube. It's not a Raytheon. Although I would like to have about twenty of these. This one is a screamer at 32-35.

MartyStrat54 · 10-29-2009, 09:39 PM

Quote:

Originally Posted by RiverRatt

I think these are the ones I was thinking about.

These are very close. They use a modified paddle getter. The basics are there and other than the "O" cut-out on the Raytheon, the plates are very similar. I would have to say that it is probably a "Philips" made tube. This would cover the 14 or so companies that Philips owned over in the UK and Europe. I would also say that this is probably a pre-1968 tube.

RiverRatt · 10-29-2009, 10:27 PM

Quote:

Originally Posted by MartyStrat54

These are very close. They use a modified paddle getter. The basics are there and other than the "O" cut-out on the Raytheon, the plates are very similar. I would have to say that it is probably a "Philips" made tube. This would cover the 14 or so companies that Philips owned over in the UK and Europe. I would also say that this is probably a pre-1968 tube.

I noticed that cutout. Isn't that common to most Raytheons?

I found a forum where the OP is asking about a Raytheon Registered tube that also has Made In Great Britain printed on it. They are speculating that it is a Brimar.

Audiophiletalk - help with 12ax7 / ecc83 stash?

Led Hendriani · 10-29-2009, 11:31 PM

Quote:

Originally Posted by MartyStrat54

This tube has a different pin out than a 12AX7 (9A pin out). The 5687 (9H pin out), although a very stout tube voltage wise, only has an amplification factor of 17.5, or about what a 12AU7 has. This will neuter your sound.

What are you trying to accomplish? Maybe one of the guys can give you some advice.

I did not really check it out too much. Someone posted on a site in order of least to most gain 12AX7 family and the 5687 was after the 7025. So I looked it up and found NOS that were originally $35 on sale for $10 since some have microphonic issues.

I guess that 7025 it is then. I really don't want to comb through 63 pages...
Could someone please tell me what are the lowest output numbers that I am needing for an ICBM?

Thanks again!

MartyStrat54 · 10-29-2009, 11:31 PM

Quote:

Originally Posted by RiverRatt

I noticed that cutout. Isn't that common to most Raytheons?

I found a forum where the OP is asking about a Raytheon Registered tube that also has Made In Great Britain printed on it. They are speculating that it is a Brimar.

Audiophiletalk - help with 12ax7 / ecc83 stash?

I looked at six Raytheons from different eras and none of them had the cut-out. I will have to pull out some different tubes tomorrow and compare them.

I went to that site, but I got bored real quick. I want info on a slant top. Oh I'm sure that we will get it figured out. Like the guy on the said on the Audiophile Talk...I installed a pair of my Amperex branded Mullards into my system. Yes, Philips even owned Mullard.

10-29-2009, 07:38 PM	#1868 (permalink)
ken361 Senior Member Join Date: Aug 2009 Posts: 235	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? 30/30 in V2 prob, be good huh? __________________ tone slut JVM 205h/1960b cab Peavey wolfgang/ EVH frankenstein pup 1959 Epiphone Les paul George L cables Mxr pedals

10-29-2009, 08:05 PM	#1870 (permalink)
Led Hendriani Junior Member Join Date: Jul 2008 Posts: 5	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? Any one know if I can use a 5687 as an exact replacement for a 12AX7 without having to modify anything? Thanks!

10-29-2009, 09:08 PM	#1881 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 918	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? I've looked at a lot of D-getter tubes trying to find a match for the Sonotone clear tops. Am I seeing seams on top?? It looks like an Amperex. I'm looking through the tubemonger stuff to see if I can find that picture again.

10-29-2009, 09:29 PM	#1885 (permalink)
RiverRatt Senior Member Join Date: May 2008 Location: Between Memphis and Nashville Posts: 918	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? I think these are the ones I was thinking about.

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