Feel free to ask Myles

[FormerOceanwaySlave]

[bump]

[Terry Buddingh]

Those mystery tubes in the photos above are Tung Sol 6550s, rebranded with the RCA logo. RCA-labeled Tung Sol 6550s were fairly common in the mid-'70s.

7552 is a date code indicating they were made the 52nd week of 1975.

Look carefully at the top of the tubes. You should see a hexagonal graphic surrounding the number 6550. This graphic is often very faint, and sometimes nonexistent, if it's been rubbed off.

Cool tubes.

[myles_rose]

Originally posted by Terry Buddingh:

Those mystery tubes in the photos above are Tung Sol 6550s, rebranded with the RCA logo. RCA-labeled Tung Sol 6550s were fairly common in the mid-'70s.

7552 is a date code indicating they were made the 52nd week of 1975.

Look carefully at the top of the tubes. You should see a hexagonal graphic surrounding the number 6550. This graphic is often very faint, and sometimes nonexistent, if it's been rubbed off.

Cool tubes.

Terry -

 

Thanks for jumping in. Its nice to see somebody from Guitar Player in these forums.

 

Have a great Christmas and New Years. Next time you are down this way give me a call. I have a few things you may want to try out and play with.

 

If I do not hear from you before NAMM, have a great holiday.

[shoe124]

Myles,

 

I am trying to set up a home studio, and have a 75 foot mogami snake out to my tracking room from the control room...I want to put my amp heads (bass and guitar) in the control room....Is it ok to use a 75 to 100 ft speaker cable from the head out to the tracking room where my cabinets are? Will it adversely affect the sound? I am currently running a 30 foot cable over the floor and through the door, but want to run it through the wall so it looks better for clients.

 

Thanks

[myles_rose]

Originally posted by shoe124:

Myles,

 

I am trying to set up a home studio, and have a 75 foot mogami snake out to my tracking room from the control room...I want to put my amp heads (bass and guitar) in the control room....Is it ok to use a 75 to 100 ft speaker cable from the head out to the tracking room where my cabinets are? Will it adversely affect the sound? I am currently running a 30 foot cable over the floor and through the door, but want to run it through the wall so it looks better for clients.

 

Thanks

This will work fine, you will loose a bit of high end but depending on the amp you can compensate for this by using a 7025 in V1.

[Vin-erator]

Originally posted by mstreck:

Myles:

 

I have a friend that owns a Fender Super Champ and one or more of the tubes have gone bad. He said he can't find the 6V6 (or the 6L6 - I can't remember). Any recommendation on where he should get these tubes?

 

Thanks,

 

Mike

Myles,

I'm not Mike's friend (nothing personal, just don't know you). I do own a Super Champ which I have just re-tubed. I'm in love again. It sounds heavenly.

 

I bring back Mike's email because I had some difficulty finding the 6C10 tube. I found on the web a supplier who was able to send me a NOS GE Compactron 6C10.

 

Do you know the function of the 6C10? In the event we Super Champ lovers can't find these, do you know of a suitable substitute?

 

Also, with all of the gain cranked, the bass really just craps out. Do you happen to have any idea if this is just because of the way the amp is wired? Might a speaker with a higher wattage capacity help this problem?

 

Thanks!

Vinny

[myles_rose]

Originally posted by ec Vinny:

Originally posted by mstreck:

Myles:

 

I have a friend that owns a Fender Super Champ and one or more of the tubes have gone bad. He said he can't find the 6V6 (or the 6L6 - I can't remember). Any recommendation on where he should get these tubes?

 

Thanks,

 

Mike

Myles,

I'm not Mike's friend (nothing personal, just don't know you). I do own a Super Champ which I have just re-tubed. I'm in love again. It sounds heavenly.

 

I bring back Mike's email because I had some difficulty finding the 6C10 tube. I found on the web a supplier who was able to send me a NOS GE Compactron 6C10.

 

Do you know the function of the 6C10? In the event we Super Champ lovers can't find these, do you know of a suitable substitute?

 

Also, with all of the gain cranked, the bass really just craps out. Do you happen to have any idea if this is just because of the way the amp is wired? Might a speaker with a higher wattage capacity help this problem?

 

Thanks!

Vinny

Vinny,

 

The 6C10 is a three triodes. If you email me at GT and ask for a print on this amp I will send one to you that will show it's functions.

[Vin-erator]

Originally posted by myles111:

Vinny,

 

The 6C10 is a three triodes. If you email me at GT and ask for a print on this amp I will send one to you that will show it's functions.[/QB]

Thanks!!!!

 

Hopefully, I have the mental capacity to read it!

vc

[shoe124]

Myles,

 

I have an fender blues deville 4x10 (probably around '93) laying around my studio and I would like to try some different cabs, but all my cab's are 16 ohms...

 

What is the ohmmage on the fender, and can I plug it into the 16 ohm cabs without hurting it?

[BillWelcome Home Studios]

Originally posted by shoe124:

Myles,

 

I am trying to set up a home studio, and have a 75 foot mogami snake out to my tracking room from the control room...I want to put my amp heads (bass and guitar) in the control room....Is it ok to use a 75 to 100 ft speaker cable from the head out to the tracking room where my cabinets are? Will it adversely affect the sound? I am currently running a 30 foot cable over the floor and through the door, but want to run it through the wall so it looks better for clients.

 

Thanks

Does it need to be 75 feet? Loss is related to distance/wire diameter. If it is only 30 feet via around and through, why does it end up being 75 feet going through the walls?

 

I use 10 gauge cable for my speakers. Lots of studios use larger, like 6. I suggest putting in wall jacks, wired with ten gauge, then make a couple of cables the right length to hit the amps, without any excess.

 

But my number one suggestion is to leave the heads in the studio, and put a driver/buffer amp in the control room to feed them, if the distance is indeed 75 feet. Or even 30 feet. Didn't Craig have a buffer amp for guitar in a project kit? I mean, there can't be that much changing you need to do on the amp head... at least, I only do a couple of tweeks, then I'm done.

 

Bill

[myles_rose]

Originally posted by shoe124:

Myles,

 

I have an fender blues deville 4x10 (probably around '93) laying around my studio and I would like to try some different cabs, but all my cab's are 16 ohms...

 

What is the ohmmage on the fender, and can I plug it into the 16 ohm cabs without hurting it?

You can use higher ohm cabs with the 2 ohm and 4 ohm Fender transformers. You cannot go the other way around though. There may be a slight drop in power at certain frequencies but it is safe.

[Vin-erator]

Originally posted by myles111:

Originally posted by shoe124:

Myles,

 

I have an fender blues deville 4x10 (probably around '93) laying around my studio and I would like to try some different cabs, but all my cab's are 16 ohms...

 

What is the ohmmage on the fender, and can I plug it into the 16 ohm cabs without hurting it?

You can use higher ohm cabs with the 2 ohm and 4 ohm Fender transformers. You cannot go the other way around though. There may be a slight drop in power at certain frequencies but it is safe.

I can only contribute here because I own this very amp. The minimum load for the extension speaker cab on the Blues DeVille is 8ohms. As Myles said, you won't have a problem with the 16 ohm cab.

[miroslav]

Myles...Questions on tube microphonics:

 

Just bought a bunch of 12AX7's along with some 6BQ5 tubes.

 

As a quick check, I'm trying them out in A Traynor Mark III...but not all the new ones at once.

 

There are (5) 12AX7's in the Mark III...and the easiest access ones, are positions V4 & V6...and positioq V5 is the 6BQ5 for the Reverb.

The V4 & V6 tubes, I beleive are part of the Reverb cicuit...from the way I'm reading the schematic.

 

OK...so I pulled V4, V5, V6...and inserted two NOS 12AX7's and one NOS 6BQ5...and then I power up and check the tubes.

 

I'm finding some of the tubes are a bit microphonic...some more, some less...including the 6BQ5's in the V5 socket.

 

I've also reversed the V4 & V6 tubes...and if the one in V4 was very microphonic...it became considerably quieter when placed in V6.

 

So...is the best way to find the best socket for each tube...to just to keep swapping them around...or do you find that most microphonic tubes will pretty much stay that way regardless where they go...???

 

If the two sides of the triode are not equally balanced...will that increase microphonics?

 

Appart from using dampers and what not...I'm just wondering if there are some better, worse ways to try and find the best positions for microphonic tubes...rahter than just toss 'em.

 

Any tips/ideas are welcome.

[miroslav]

Well...I tried some of those NOS 12AX7's in my other Traynor Amp (YCV40WR) in the V1 and V2 positions.

 

Thought they do exibit some microphonics when I tap on them...they also sound real nice compared to the stock Sovteks (also had some microphonics) that were in there.

I have another dozen NOS Sylvania/GE to try out...but the amp already sounds way better!

 

I also got four RCA black plate 6L6GB's, clear top, double-D bottom getters...used, but still quite strong, and they sound excellent...

...again, way better than the stock Sovtek 5881's.

 

I also tried some JAN Philips 6L6WGB's...and they are nice...but with a bit "harder" mids.

 

So...what I am seeing is that even though some of the tubes exibit microphonics...they still put out great tones.

 

Therefore, I would say that there needs to be some tube resonance....as it gives it it's tone/character...yes?

 

I think I'll get some of those O-ring dampers and that should help out.

[miroslav]

bump...

[myles_rose]

Originally posted by miroslav:

Myles...Questions on tube microphonics:

 

Just bought a bunch of 12AX7's along with some 6BQ5 tubes.

 

As a quick check, I'm trying them out in A Traynor Mark III...but not all the new ones at once.

 

There are (5) 12AX7's in the Mark III...and the easiest access ones, are positions V4 & V6...and positioq V5 is the 6BQ5 for the Reverb.

The V4 & V6 tubes, I beleive are part of the Reverb cicuit...from the way I'm reading the schematic.

 

OK...so I pulled V4, V5, V6...and inserted two NOS 12AX7's and one NOS 6BQ5...and then I power up and check the tubes.

 

I'm finding some of the tubes are a bit microphonic...some more, some less...including the 6BQ5's in the V5 socket.

 

I've also reversed the V4 & V6 tubes...and if the one in V4 was very microphonic...it became considerably quieter when placed in V6.

 

So...is the best way to find the best socket for each tube...to just to keep swapping them around...or do you find that most microphonic tubes will pretty much stay that way regardless where they go...???

 

If the two sides of the triode are not equally balanced...will that increase microphonics?

 

Appart from using dampers and what not...I'm just wondering if there are some better, worse ways to try and find the best positions for microphonic tubes...rahter than just toss 'em.

 

Any tips/ideas are welcome.

Your preamp tubes should not be microphonic.

[miroslav]

Originally posted by myles111:

Your preamp tubes should not be microphonic.

OK...I kinda' understood that to be the best-case situation...

 

Thing is...as I mentioned...I noticed that a given tube when placed in one position (V1) was more microphonic than when placing same tube in the V2 position.

 

I was asking if position, along with the actual tube makeup, worked together to give more/less microphonics?

Also...is it posible to anticipate a potentially microphonic tube by it's readings, and the balance between the two sides of the triode...

...or is that not relevent at all?

 

I guess it's sometimes puzzling that you have some good quality tubes that read very well...

...and then you stick them in one position and tap...and notice the high microphinics...???

So is that it...just the ol' tap-test, regardlessf their other quality?

 

Also...you specifically say no preamp tube should be microphinc...but, what about the power tubes....'cuz I notice that they too can exibit microphonics.

 

Also...I've heard a lot of folks state that almost all tubes can have some degree of microphinics...

...and I must agree, since all the ones I tried out....more or less, when tapped...will ring...but only some seem to be heard at all during actual playing.

 

Do those silicone/rubber O-rings/dampers help at all with those tubes that show very marginal microphinics?

 

Thanks!

[myles_rose]

Originally posted by miroslav:

Originally posted by myles111:

Your preamp tubes should not be microphonic.

OK...I kinda' understood that to be the best-case situation...

 

Thing is...as I mentioned...I noticed that a given tube when placed in one position (V1) was more microphonic than when placing same tube in the V2 position.

 

I was asking if position, along with the actual tube makeup, worked together to give more/less microphonics?

Also...is it posible to anticipate a potentially microphonic tube by it's readings, and the balance between the two sides of the triode...

...or is that not relevent at all?

 

I guess it's sometimes puzzling that you have some good quality tubes that read very well...

...and then you stick them in one position and tap...and notice the high microphinics...???

So is that it...just the ol' tap-test, regardlessf their other quality?

 

Also...you specifically say no preamp tube should be microphinc...but, what about the power tubes....'cuz I notice that they too can exibit microphonics.

 

Also...I've heard a lot of folks state that almost all tubes can have some degree of microphinics...

...and I must agree, since all the ones I tried out....more or less, when tapped...will ring...but only some seem to be heard at all during actual playing.

 

Do those silicone/rubber O-rings/dampers help at all with those tubes that show very marginal microphinics?

 

Thanks!

Generally, the first gain stage, in most amps V1 will show the worst attributes of a tube, and is the most critical location. This is where you want the best quality tube ... tone wise, lack of noise wise, and lack of microphonics wise. In may amps, changing from a 12AX7C to a 12AX7R2 or ECC83S will change the character of the amp too.

[snoz65]

Hi Myles,

 

I am looking at some 'RCA' 12ax7/7025 tubes to try out. The ones that I'm interested in are reportedly 'the re-issue series made by TESLA'

They are NOS, unmarked and in RCA boxes.

http://i17.ebayimg.com/01/i/02/7e/f7/8a_1.JPG

http://i18.ebayimg.com/01/i/02/7f/0d/67_1.JPG

 

Do you know anything about these 're-issues' or are they simply re-boxed Teslas. Why would they not be marked with anything? Any experience with 'em?

 

Thanx bud,

Shauno.

[BlueZet]

I want to split my guitar signal, so I can have

 

-->effects-->

gtr amp

------------>

 

in order to retain the initial attack and ADD the overdrive/chorus/delay sound

 

I heard this is possible but NOT very good with just a Y-cord, and that I would need a splitter box - is this correct and can I make one myself?

[myles_rose]

Originally posted by snoz65:

Hi Myles,

 

I am looking at some 'RCA' 12ax7/7025 tubes to try out. The ones that I'm interested in are reportedly 'the re-issue series made by TESLA'

They are NOS, unmarked and in RCA boxes.

http://i17.ebayimg.com/01/i/02/7e/f7/8a_1.JPG

http://i18.ebayimg.com/01/i/02/7f/0d/67_1.JPG

 

Do you know anything about these 're-issues' or are they simply re-boxed Teslas. Why would they not be marked with anything? Any experience with 'em?

 

Thanx bud,

Shauno.

These look exactly like the current JJ ECC83 and that tube is completely different than any of the older RCA tubes. They also sound completely different. I have no experience with a JJ copy of an RCA tube that is shown here.

[myles_rose]

Originally posted by badblues:

I want to split my guitar signal, so I can have

 

-->effects-->

gtr amp

------------>

 

in order to retain the initial attack and ADD the overdrive/chorus/delay sound

 

I heard this is possible but NOT very good with just a Y-cord, and that I would need a splitter box - is this correct and can I make one myself?

Use a buffer or a proper buffered A/B/Y switch. Using a common Y cord will cause your guitar pickup to not see the proper load. This is no biggie, and may even be almost not perceptible in a lot of cases but it is not the best way to do things.

[miroslav]

Odd question about 6L6/5881 tubes.

 

I have a bunch of 'em now...

 

Pair of Philips JAN 6L6WGB - '70

 

Pair of Sovtek 5881WXT - '02

 

2 pair of RCA 6L6GB - '59

 

Pair of Tung-SOl 6L6GB - '58

 

Pair of Philco 6L6GB - '57

 

So here's the odd thing I just realized...

 

the 2 RCA and Philco 6L6GB have 7 pins, with a pin at position 1, and only position 6 is empty...

 

...whereas the others (6L6WGB/5881), including the Tung-Sol 6L6GB have the usual 6 pins with no pins at positions 1 & 6.

 

OK...what's with the extra pin at #1...???

 

I've already tired them in my amp...and all work fine, regardless of pin count.

 

Is there something different with the RCA and Philco GBs....and then why do the Tung-Sol GBs have just 6 pins...???

 

Just one of those...DUH???...moments.

[snoz65]

Originally posted by myles111:

Originally posted by snoz65:

Hi Myles,

 

I am looking at some 'RCA' 12ax7/7025 tubes to try out. The ones that I'm interested in are reportedly 'the re-issue series made by TESLA'

They are NOS, unmarked and in RCA boxes.

http://i17.ebayimg.com/01/i/02/7e/f7/8a_1.JPG

http://i18.ebayimg.com/01/i/02/7f/0d/67_1.JPG

 

Do you know anything about these 're-issues' or are they simply re-boxed Teslas. Why would they not be marked with anything? Any experience with 'em?

 

Thanx bud,

Shauno.

These look exactly like the current JJ ECC83 and that tube is completely different than any of the older RCA tubes. They also sound completely different. I have no experience with a JJ copy of an RCA tube that is shown here.

Thanks Miles, you are absolutely correct. I already bought two of these and when they arrived I checked them against a JJ ECC83s and they are exactly the same!

I plugged them into my Marshall, replacing a Blackburn Mullard and of course there is NO comparison. These are much brighter and kinda thin sounding, not as much body about their tone. So I feel kind of ripped off by this ebayer who is apparently rubbing off the 'JJ' label and putting them int RCA 7025 boxes. At least they were fairly cheap. Thanks again,

Shaun.

\'RCA 7025\' auction.

[miroslav]

Originally posted by PBBPaul:

What are the typical characteristics of these? If I want to replace them, what should I look for? I don't have a schematic but I assume that the 12AX7 is the phase inverter.

You guys may already have this link bookmarked...

...but I found this site while google-ing for tube data.

 

TUBE DATA

 

I don't know how accurate his data is (maybe Myles can comment)...but he has a decent searchable database and it also cross-references tubes in the same family.

 

Just click on the TUBE DATA button on his main pageand then you can search out characteristics of various tubes.

[myles_rose]

Originally posted by miroslav:

Odd question about 6L6/5881 tubes.

 

I have a bunch of 'em now...

 

Pair of Philips JAN 6L6WGB - '70

 

Pair of Sovtek 5881WXT - '02

 

2 pair of RCA 6L6GB - '59

 

Pair of Tung-SOl 6L6GB - '58

 

Pair of Philco 6L6GB - '57

 

So here's the odd thing I just realized...

 

the 2 RCA and Philco 6L6GB have 7 pins, with a pin at position 1, and only position 6 is empty...

 

...whereas the others (6L6WGB/5881), including the Tung-Sol 6L6GB have the usual 6 pins with no pins at positions 1 & 6.

 

OK...what's with the extra pin at #1...???

 

I've already tired them in my amp...and all work fine, regardless of pin count.

 

Is there something different with the RCA and Philco GBs....and then why do the Tung-Sol GBs have just 6 pins...???

 

Just one of those...DUH???...moments.

In a 6L6 or 5881 not all eight pins are used. Sometimes they are left out of the base, sometimes they are inserted in the base and just not connected internally.

[myles_rose]

Originally posted by snoz65:

Originally posted by myles111:

Originally posted by snoz65:

Hi Myles,

 

I am looking at some 'RCA' 12ax7/7025 tubes to try out. The ones that I'm interested in are reportedly 'the re-issue series made by TESLA'

They are NOS, unmarked and in RCA boxes.

http://i17.ebayimg.com/01/i/02/7e/f7/8a_1.JPG

http://i18.ebayimg.com/01/i/02/7f/0d/67_1.JPG

 

Do you know anything about these 're-issues' or are they simply re-boxed Teslas. Why would they not be marked with anything? Any experience with 'em?

 

Thanx bud,

Shauno.

These look exactly like the current JJ ECC83 and that tube is completely different than any of the older RCA tubes. They also sound completely different. I have no experience with a JJ copy of an RCA tube that is shown here.

Thanks Miles, you are absolutely correct. I already bought two of these and when they arrived I checked them against a JJ ECC83s and they are exactly the same!

I plugged them into my Marshall, replacing a Blackburn Mullard and of course there is NO comparison. These are much brighter and kinda thin sounding, not as much body about their tone. So I feel kind of ripped off by this ebayer who is apparently rubbing off the 'JJ' label and putting them int RCA 7025 boxes. At least they were fairly cheap. Thanks again,

Shaun.

\'RCA 7025\' auction.

You have to watch out on ebay, and from some other folks too.

 

Some of the biggest scams are more sophisticated.

 

1. Taking current Ei long plate tubes and silkscreening the Telefunken logo on them. They came off the same tooling but the materials are different. One tube is magic to some but the Ei is not magic to most. Look for a diamond in the base of real Telefunkens.

 

2. Relabelling GZ-34 tubes that are current $25 tubes with a Mullard logo and selling for $150.00+

 

3. The GT-12AX7M is a reissue of the original right down to the materials. Some folks are now buying these and removing the GT silkscreen and rescreening as original Mullards. This is pretty easy to find fakes though. Aspen (head of GT) was concerned that this might happen so when the bottle was tooled GT went to a slightly larger diameter bottle. If you ever suspect a fake Mullard give me a call or drop me a line.

 

I have seen a LOT of RCA 6L6 tubes that are Chinese but rescreened with the RCA logo.

[myles_rose]

Originally posted by miroslav:

Originally posted by PBBPaul:

What are the typical characteristics of these? If I want to replace them, what should I look for? I don't have a schematic but I assume that the 12AX7 is the phase inverter.

You guys may already have link this bookmarked...

...but I found this site while googloing for tube data.

 

TUBE DATA

 

I don't know how accurate his data is (maybe Myles can comment)...but he has a decent searchable database and it also cross-references tubes in the same family.

 

Just click on the TUBE DATA button on his main pageand then you can search out characteristics of various tubes.

I have not seen this site but the typical hamm radio guy is a lot more tube smart that 90% of the people that work on guitar amps actually ... so, this may be a great site.

 

Another great tube data site is www.duncanamps.com

[WaterMan]

Myles,

 

You referred me to the DS-1 for my Maz 18 Jr, and it does sound good. Thought I might tweek it a bit, however; maybe smooth out some rough edges. Any thoughts on the Keeley vs AnalogMan mods for this pedal?

[myles_rose]

Originally posted by WaterMan:

Myles,

 

You referred me to the DS-1 for my Maz 18 Jr, and it does sound good. Thought I might tweek it a bit, however; maybe smooth out some rough edges. Any thoughts on the Keeley vs AnalogMan mods for this pedal?

I use the pedal stock.