Feel free to ask Myles

[Dave da Dude]

quote:

--------------------------------------------------------------------------------

Originally posted by Dave th Dude:

Myles, I am just about to receive (it's shipping today) my first tube amp (Randall Pro 1000, 1993).

 

I seem to remember somewhere in the deep, dark recesses of my memory (boy it's scary in there) something about the handling of tubes that said the oil from your fingers (that create fingerprints), if left on a power tube, will create a hot spot and cause early failure.

 

Is there any truth to this? Or was I just smoking wacky tobacee?

 

Dave

--------------------------------------------------------------------------------

quote:

 

Dave,

 

I guess from a pure physics point of view this may have some point, but tubes are not like halogen bulbs. They are more like conventional light bulbs, and I do not wear gloves when I replace light bulbs or tubes.

 

The main point of handling tubes is .... watch out for leaving some of your skin on output tubes when they are super hot ... won't hurt the tube much, but causes people a bit of pain

 

Regards,

 

--------------------

Myles S. Rose

 

That's IT ! Halogen bulbs. I knew I remembered that from somewhere. I don't wear gloves to replace light bulbs either.

 

Thanks for jogging my web clouded memory, Dave.

[rsf1977]

Hey Myles I was looking at my Dual Rect manual and this is what it says for the preamp:

 

V1 A= Input Stage

V1 B= NOT USED

V2 A= 2nd Stage

V2 B= 3rd Stage

V3 A= 4th Stage

V3 B= 5th Stage

 

V4 A= FX Send

V4 B= FX Return

V5 A/B= Phase Splitter/Output

 

If V1 is the Phase Inverter and the B side of the V1 position is not used does that mean a matched 12AX7 wont do anything or should I still get a matched one anyway?

 

Also should I use the 12AX7EHs for all the positions or do some tubes work better in certain applications generally, just wondering your opinion on this?

[myles_rose]

Originally posted by rsf1977:

Hey Myles I was looking at my Dual Rect manual and this is what it says for the preamp:

 

V1 A= Input Stage

V1 B= NOT USED

V2 A= 2nd Stage

V2 B= 3rd Stage

V3 A= 4th Stage

V3 B= 5th Stage

 

V4 A= FX Send

V4 B= FX Return

V5 A/B= Phase Splitter/Output

 

If V1 is the Phase Inverter and the B side of the V1 position is not used does that mean a matched 12AX7 wont do anything or should I still get a matched one anyway?

 

Also should I use the 12AX7EHs for all the positions or do some tubes work better in certain applications generally, just wondering your opinion on this?

Hey Myles I was looking at my Dual Rect manual and this is what it says for the preamp:

 

V1 A= Input Stage

(this is where you want a high gain tube)

V1 B= NOT USED

 

V2 A= 2nd Stage

(this is where you want the 2nd high gain tube)

V2 B= 3rd Stage

 

V3 A= 4th Stage

V3 B= 5th Stage

 

V4 A= FX Send

V4 B= FX Return

V5 A/B= Phase Splitter/Output

(this is where you want the matched phase inverter, not V1.

 

Only use the MPI in V5.

 

If you want more gain in the other channels, then you can put a high output tube also in V3, but since V3 is fed off earlier stages, you may have so much front end gain that you loose articulation and anything above "2" or so will not be useful anymore as it will be too distorted in the front end.

 

I prefer the GT-12AX7R3 in those amps. That is the same tube as the 12AX7EH but selected a bit more closely.

 

Regards,

[rsf1977]

Thanks Myles for all your help.

You mentioned earlier about using the 6L6GE or the 6L6-S at a ratting of 6-7. I just wanted to know the tonal qualities of each tube and why you suggested both. I am also not familiar with the 6L6-S who makes these?

 

Also so what do I stick in the V3? another EH12AX7 with low gain or another kind of tube? Sorry if I'm a little slow on this stuff I've only recently become addicted to knowing everything I can about my gear and everything else, my girlfriend thinks I'm crazy...

[snoz65]

Hi there Miles,

I am looking for a new preamp tube for the first position of channel 2 and 3 of my Marshall 30th aniversary. I currently have an old Brimar 12AX7 which has gone microphonic and I am seriously considering some Mullard CV4004's as a replacement.

Do you have any comments or experience with these Mullards and why are they known as CV4004's rather than 12AX7's.

Regards,

Shaun.

[myles_rose]

Originally posted by rsf1977:

Thanks Myles for all your help.

You mentioned earlier about using the 6L6GE or the 6L6-S at a ratting of 6-7. I just wanted to know the tonal qualities of each tube and why you suggested both. I am also not familiar with the 6L6-S who makes these?

 

Also so what do I stick in the V3? another EH12AX7 with low gain or another kind of tube? Sorry if I'm a little slow on this stuff I've only recently become addicted to knowing everything I can about my gear and everything else, my girlfriend thinks I'm crazy...

rsf1977,

 

The 6L6S has more of a midrange bump and is less linear than the GE. It's really a matter of personal preference. The sound image is larger by about 10-15 degrees with the GE's but a lot of hard rock players love the "in your face" aspects of the 6L6S. The 6L6S is made by the JJ factory.

 

In V3, you can use most anything as the initial gain and tone have already been set and defined for the most part by V1.

 

Regards,

[myles_rose]

Originally posted by snoz65:

Hi there Miles,

I am looking for a new preamp tube for the first position of channel 2 and 3 of my Marshall 30th aniversary. I currently have an old Brimar 12AX7 which has gone microphonic and I am seriously considering some Mullard CV4004's as a replacement.

Do you have any comments or experience with these Mullards and why are they known as CV4004's rather than 12AX7's.

Regards,

Shaun.

Shaun,

 

CV4004 is just another designation that has been used at times. The Mullard CV is in the same family as the 12AX7, ECC83, 7025, etc, but has its own unique plate structure and some other unique aspects that give it it's tonal qualitles.

 

These are great in V1 of a Marshall (or just about any other amp) as they had very high Quality Control and at least you generally get a tube that is putting out what it was supposed to put out. It is also very articulate and all in all, just a beautiful sounding tube in general.

 

Regards,

[Seth]

Hi Myles,

 

I'm looking to maximize my Peavey Classic VT 50 for blues.

 

That's the model with the SS front end, a multitude of channels with an "automix" (cascades one channel into the other for an extra muddy sound) feature, and 2 6L6GC's for power. I got these from Bob at Eurotubes.

 

2 - 12" Eminence OEM speakers.

 

By bridging the bright channel into one of the normal inputs, and by very careful eq-ing and gain adjustment, I can get a "pretty good" sound with very little (but some!) ss harshness buried in the background.

 

Any ideas how I might be able to take this platform further?

 

Thanks.

[myles_rose]

Originally posted by Seth:

Hi Myles,

 

I'm looking to maximize my Peavey Classic VT 50 for blues.

 

That's the model with the SS front end, a multitude of channels with an "automix" (cascades one channel into the other for an extra muddy sound) feature, and 2 6L6GC's for power. I got these from Bob at Eurotubes.

 

2 - 12" Eminence OEM speakers.

 

By bridging the bright channel into one of the normal inputs, and by very careful eq-ing and gain adjustment, I can get a "pretty good" sound with very little (but some!) ss harshness buried in the background.

 

Any ideas how I might be able to take this platform further?

 

Thanks.

Seth,

 

The 6L6 JJ tubes are a bit "in your face" for blues, and with your SS front end, may be even a bit more sterile.

 

I would go to something like an NOS 5881 or a KT-66, and with something in the rating area of a GT #3-4.

 

Regards,

[Seth]

Originally posted by myles111:

Originally posted by Seth:

Hi Myles,

 

I'm looking to maximize my Peavey Classic VT 50 for blues.

 

That's the model with the SS front end, a multitude of channels with an "automix" (cascades one channel into the other for an extra muddy sound) feature, and 2 6L6GC's for power. I got these from Bob at Eurotubes.

 

2 - 12" Eminence OEM speakers.

 

By bridging the bright channel into one of the normal inputs, and by very careful eq-ing and gain adjustment, I can get a "pretty good" sound with very little (but some!) ss harshness buried in the background.

 

Any ideas how I might be able to take this platform further?

 

Thanks.

Seth,

 

The 6L6 JJ tubes are a bit "in your face" for blues, and with your SS front end, may be even a bit more sterile.

 

I would go to something like an NOS 5881 or a KT-66, and with something in the rating area of a GT #3-4.

 

Regards,

Thanks Myles!

 

This is a "fixed bias" amp, but I'm very ignorant about biasing.

 

If I try 5881's or KT-66's will I need to have a tech do any biasing or adjusting?

 

I've heard that KT-66's are large. How much space do I need for them to be an option?

 

Thanks again for anly info.

[rsf1977]

Hey Myles not that I'm doubting your knowledge, but I thought maybe you could respond to what someone told me on Harmony-Central when I asked about the new GE6L6:

 

"You might like to know that at least one, and maybe more, boutique amp builder has disliked the the new GT 6L6 enough to ask Miles to stop recommending it for their amps. They do not feel that it is a good sounding tube, despite how and where it was made. Please remember that Myles is a paid employee of Groove Tubes and you should take that into consideration when thinking about his "advice".

 

Just something to think about!"

 

http://acapella.harmony-central.com/forums/showthread.php?s=1aa7ca5ab0a848e4f30f5f9c4557e452&postid=324392

[myles_rose]

Originally posted by Seth:

Originally posted by myles111:

Originally posted by Seth:

Hi Myles,

 

I'm looking to maximize my Peavey Classic VT 50 for blues.

 

That's the model with the SS front end, a multitude of channels with an "automix" (cascades one channel into the other for an extra muddy sound) feature, and 2 6L6GC's for power. I got these from Bob at Eurotubes.

 

2 - 12" Eminence OEM speakers.

 

By bridging the bright channel into one of the normal inputs, and by very careful eq-ing and gain adjustment, I can get a "pretty good" sound with very little (but some!) ss harshness buried in the background.

 

Any ideas how I might be able to take this platform further?

 

Thanks.

Seth,

 

The 6L6 JJ tubes are a bit "in your face" for blues, and with your SS front end, may be even a bit more sterile.

 

I would go to something like an NOS 5881 or a KT-66, and with something in the rating area of a GT #3-4.

 

Regards,

Thanks Myles!

 

This is a "fixed bias" amp, but I'm very ignorant about biasing.

 

If I try 5881's or KT-66's will I need to have a tech do any biasing or adjusting?

 

I've heard that KT-66's are large. How much space do I need for them to be an option?

 

Thanks again for anly info.

I would have a tech check the bias, and remember, the KT-66 is a 25 watt tube, a bit different than some 5881's or some 6L6's.

 

On height, give yourself at least 4 7/8".

 

Regards,

[myles_rose]

Originally posted by rsf1977:

Hey Myles not that I'm doubting your knowledge, but I thought maybe you could respond to what someone told me on Harmony-Central when I asked about the new GE6L6:

 

"You might like to know that at least one, and maybe more, boutique amp builder has disliked the the new GT 6L6 enough to ask Miles to stop recommending it for their amps. They do not feel that it is a good sounding tube, despite how and where it was made. Please remember that Myles is a paid employee of Groove Tubes and you should take that into consideration when thinking about his "advice".

 

Just something to think about!"

rsf1977 ...

 

Interesting news to me, but everybody is entitled to their opinion. It would be nice to know who the "boutique" maker was that did not like the tube, as some feedback would be nice, but since the first 6 month run off the GE's were gone in 3 1/2 weeks, most folks may tend to feel differently than the "boutique" amp maker I guess.

 

Regards,

[rsf1977]

so no one has told you to stop recommending them? or anything? Have the tubes been getting positive feedback from users or is it to early to tell?

[sgguitarzz]

Hey Myles. Still searching for that small amp. I have decided that the Blues Jr. is too small. I am now currently checking out the Peavey Delta Blues amps but can't decide on 1x15 or 2x10. Do you have any experience with these and tube recommendations? Thanks.

 

Dennis

[myles_rose]

Originally posted by rsf1977:

so no one has told you to stop recommending them? or anything? Have the tubes been getting positive feedback from users or is it to early to tell?

The only person that has said something to me has been Ed from THD where I mention the GE and reference a review on the original GE that Watford Valves had written. Since during testing, the curves, specs, parts, and every other aspect was identical to the original GE, right down to the machines they are made on, I felt it was OK to reference that review. Ed did not like me using an old review on the new GE in the same reference as the THD Univalve name, possibly as GT has a similar product that competes in some markets with the Univalve. Both amps have their strong points, and I personally own a Univalve, but when I get the money, I will also purchase a GT Solo-Single.

 

The feedback from those that have used or purchased the 6L6GE has been more positive than was expected. In the initial 6 month run, the tubes were gone in less than a month. The second run was completed, and the tubes are now back in stock. One pretty famous 5150 user purchased a LOT of them, all that GT was willing to ship to a single individual. In the past, this fellow used the NOS GE's in his amps.

 

Regards,

[myles_rose]

Originally posted by sgguitarzz:

Hey Myles. Still searching for that small amp. I have decided that the Blues Jr. is too small. I am now currently checking out the Peavey Delta Blues amps but can't decide on 1x15 or 2x10. Do you have any experience with these and tube recommendations? Thanks.

 

Dennis

Dennis,

 

I'd post that question here, and over at Harmony Central. You'll probably get a lot of responses. Also check the Harmony Central user's review, as there is a lot of good feedback there.

 

I like 2x10 configs a lot, as the speaker cones are lighter than a 12" (and much lighter than a 15"), have nice midrange detail because of less cone mass in a lot of cases, and provide good low end when 2 10's are used.

 

Myles

[rsf1977]

Cool, just wondering don't mean to put you on the spot. Well I ordered the GE6L6 I'll let you know how it goes when I get them and popem' in my Dual Rect. Thanks for the help.

 

Do you know if there is a backorder wait and if there have been any changes with the second run of these tubes like any adjustments for the better? Thanks.

[myles_rose]

Originally posted by rsf1977:

Cool, just wondering don't mean to put you on the spot. Well I ordered the GE6L6 I'll let you know how it goes when I get them and popem' in my Dual Rect. Thanks for the help.

 

Do you know if there is a backorder wait and if there have been any changes with the second run of these tubes like any adjustments for the better? Thanks.

rsf1977,

 

There is no backorder as the 2nd run was finished on last Thursday and the first 200 finished testing on Monday (two days ago). Just as a matter of info, out of the first 200, there was a 0% reject rate, which is quite unique compared to the up to 50% reject rate on some other tubes.

 

Regards,

[El Glom-o]

Hi, Myles - Are you familiar with the Tel-Ray Adineko device, sometimes referred to as the "oil-can reverb"? I have a couple of them that I'd like to have in optimum working condition. I've gathered info about them, including schematic and owner's instructions for the Gibson GA4-RE (Gibson's version), as well as copies of the patents for the device, but I've been unable to find service or troubleshooting info. Can you help me with this? Either with advice or perhaps with servicing it yourself?

[El Glom-o]

Hi, Myles - Are you familiar with the Tel-Ray Adineko device, sometimes referred to as the "oil-can reverb"? I have a couple of them that I'd like to have in optimum working condition. I've gathered info about them, including schematic and owner's instructions for the Gibson GA4-RE (Gibson's version), as well as copies of the patents for the device, but I've been unable to find service or troubleshooting info. Can you help me with this? Either with advice or perhaps with servicing it yourself?

[rsf1977]

hey Myles is there someone out there that knows as much about guitars as you do about amps I can ask stuff.

[myles_rose]

Originally posted by El Glom-o:

Hi, Myles - Are you familiar with the Tel-Ray Adineko device, sometimes referred to as the "oil-can reverb"? I have a couple of them that I'd like to have in optimum working condition. I've gathered info about them, including schematic and owner's instructions for the Gibson GA4-RE (Gibson's version), as well as copies of the patents for the device, but I've been unable to find service or troubleshooting info. Can you help me with this? Either with advice or perhaps with servicing it yourself?

The hot shot on these is a guy named Jimmy who is the tech at Groove Tubes.

 

He can be reached at 818-361-4500, just ask for Jimmy, or I think his email is:

 

lab@groovetubes.com

 

Regards,

[myles_rose]

Originally posted by rsf1977:

hey Myles is there someone out there that knows as much about guitars as you do about amps I can ask stuff.

The best guitar folks around that I know are:

 

David Neely ... a guitar builder from Nashville that is in So Cal now. On my website there is a link to him (his website) and he has an email there where you can write him or call him also. Tell him I said hello.

 

"The Amazing Nick" at Norm's Rare Guitars .... also a link on my website with contact info. If you know who Norm Harris is, and realize that Nick is the one that does all his repair and restoration work, then that gives you an idea about Nick. If Nick seems "harsh", its just his personality, and he's really a fun guy but some folks do not understand his humor. Some folks that can give him references are folks like Van Halen, David Lee Roth, and folks from the Jazz and Blues world from decades.

 

Those are the two best guys for my money.

 

Regards,

[Skapunxter]

Hey myles got a couple of questions for you:

First off i got a rocktron piranha preamp the other day and noticed that the hi-gain channel is kinda cheezy sounding. I can get some good distortoin outta it, but i want more thick shred and not so much tinny biting tone and theres just something it lacks, and i gotta play with the eq a bunch to get it sounding how i like it. Is it probable that this is the result of a crappy pair of tubes? its a real pain in the ass to open this preamp up, so if it wont really help too much id rather not risk anything.

 

Next question: I run this piranha into a peavy classic 50/50. One channel has a quartet of GT el84's #7, and the other channel has a new set of sovteks i think. This preamp/poweramp combination can really scream at a low volume... sounds really nice. But when i crank them up, it just doesnt seem to put out the advertised 100 watts. I have a hard time keeping up with the rest of the band in terms of balaced volume. When i do max out all my volume knobs it is (barely) loud enough, but sounds flabby and my tone looses all its balls. All my patches start to sound really alike. What can i tweak to fix this problem, or is it just going to be like that forever? I can go into each of my patches and max out their levels, but that doesnt leave me with a lot of room for level variation beween patches. I also Have an ADA mp-1 and it sounds pretty loud through the 50/50, but still not near loud enough. Im getting my ass drowned out by a peavey ultra 100 watt head with its volume on 5. Something just doesnt seem right... Thanks a ton.

randy

[El Glom-o]

[/qb]

The hot shot on these is a guy named Jimmy who is the tech at Groove Tubes.[/QB]

 

I just spoke to Jimmy. He was quite helpful. Thank you.

 

El Glom-o

[dave251]

Myles- Been a while...thought I'd fill you in on the electroCoustic amp project/progress...

 

We've settled on a tube layout...#2 will have a pair of 12AX7's, a 6SL7 for the driver and a pair of 300B's for output. It will have a buffered EFX loop, and Hammond transformers. SS recto. We feel like we can eliminate the big filter choke...Brett routed around it on the first one and didn't have any added noise problems. We're going to DC for the filament heater...

 

With any kind of luck we'll have this one together by midsummer...and in a cab ready for demo shortly thereafter...I'd like to be building my first "production" amp by the first of the year...this will be quite a plunge for this old woodbutcher...but I'd sure like to be able to build the whole shootin' match...guitar AND amp. Speaking of which...here's a pic of the latest delivery...

 

We need recommendations on the best/most consistently available 12AX7 for our purposes....preamp stage and EFX buffering...

 

Regards, Dave

 

http://electrocoustic.com/newimage/kessler%20front.jpg

[myles_rose]

Originally posted by El Glom-o:

[/qb]

The hot shot on these is a guy named Jimmy who is the tech at Groove Tubes.

 

I just spoke to Jimmy. He was quite helpful. Thank you.

 

El Glom-o[/QB]

 

El Glom-o ... you are welcome.

 

Myles

[myles_rose]

Originally posted by Skapunxter:

Hey myles got a couple of questions for you:

First off i got a rocktron piranha preamp the other day and noticed that the hi-gain channel is kinda cheezy sounding. I can get some good distortoin outta it, but i want more thick shred and not so much tinny biting tone and theres just something it lacks, and i gotta play with the eq a bunch to get it sounding how i like it. Is it probable that this is the result of a crappy pair of tubes? its a real pain in the ass to open this preamp up, so if it wont really help too much id rather not risk anything.

 

Next question: I run this piranha into a peavy classic 50/50. One channel has a quartet of GT el84's #7, and the other channel has a new set of sovteks i think. This preamp/poweramp combination can really scream at a low volume... sounds really nice. But when i crank them up, it just doesnt seem to put out the advertised 100 watts. I have a hard time keeping up with the rest of the band in terms of balaced volume. When i do max out all my volume knobs it is (barely) loud enough, but sounds flabby and my tone looses all its balls. All my patches start to sound really alike. What can i tweak to fix this problem, or is it just going to be like that forever? I can go into each of my patches and max out their levels, but that doesnt leave me with a lot of room for level variation beween patches. I also Have an ADA mp-1 and it sounds pretty loud through the 50/50, but still not near loud enough. Im getting my ass drowned out by a peavey ultra 100 watt head with its volume on 5. Something just doesnt seem right... Thanks a ton.

randy

Randy ....

 

On your Rocktron, there is a lot of processing and EQ in there already, so the sound it makes is, well, sort of the sound it makes. If you change anything inside, it won't do much as there are too many other things going on and the signal path is anything but simple.

 

The Sovtek's don't have anywhere near the output sound image of the JJ (EL-84-s) tubes. They may also be far from being close to match also. If you are in my area (So Cal), I would be happy to scope your amp and let you know actual power output. (I do this for no charge for forum folks from here .... and I also adjust bias for N/C if you are a player that is NOT signed or NOT famous, and just are trying to get by like most of us. If you have an agent, manager, or record label, then you PAY ... LOTS).

 

What you should do is put in all new EL-84's. Also make sure the driver tube (called the phase inverter in a lot of amps) is also fresh on each output set.

 

If you want another tip, email me about this from my website as there are some things I would mention but would not think this forum is the proper avenue.

 

Regards,

[myles_rose]

Originally posted by dave251:

Myles- Been a while...thought I'd fill you in on the electroCoustic amp project/progress...

 

We've settled on a tube layout...#2 will have a pair of 12AX7's, a 6SL7 for the driver and a pair of 300B's for output. It will have a buffered EFX loop, and Hammond transformers. SS recto. We feel like we can eliminate the big filter choke...Brett routed around it on the first one and didn't have any added noise problems. We're going to DC for the filament heater...

 

With any kind of luck we'll have this one together by midsummer...and in a cab ready for demo shortly thereafter...I'd like to be building my first "production" amp by the first of the year...this will be quite a plunge for this old woodbutcher...but I'd sure like to be able to build the whole shootin' match...guitar AND amp. Speaking of which...here's a pic of the latest delivery...

 

We need recommendations on the best/most consistently available 12AX7 for our purposes....preamp stage and EFX buffering...

 

Regards, Dave

 

Dave,

 

Its great to hear you are progressing.

 

On 12AX7's, frankly, today's 12AX7's have tolerances that are so wide ( from 0.6mA to 1.8mA ) that it is just hopeless to suggest any off the shelf one that would work best in your amp.

 

You are not going to sell 100,000 of these (well, if you do, then we'll deal with that), but for limited production of a very high end amp like yours, I'd go with selected 12AX7R3 tubes. These are available from the SAG (Special Applications Group) over at Groove Tubes. Actually, that is how I ended up at GT last month, as I needed more and more selected tubes all the time for my own clients.

 

I'd go with a "medium" selection as the rise time will be really nice in that amp, but on the high side of the medium range so the rise time is on the fast side of medium ... to keep the articulation and attack of an acoustic instrument.

 

You can see these tubes at: http://www.groovetubes.com/product.cfm?Product_ID=1733

 

For your amp I'd specify a rating of 85-95.

 

I would also be happy to put you in contact with the head of GT sales as since you are an amp maker, you'd probably have a corporate account set up with whatever associated discounts sales does with those sort of folks.

 

Keep me informed!

 

Myles