[Feel free to ask Myles]

Originally posted by myles111:

James ... cool tubes ... Fivre was the RCA in Italy, using RCA tooling. Cool 50s stuff you have there, maybe even 40s.

 

In the UV I would use these in the low voltage setting ... they will take the high voltage, but hV in the UV is over 450 volts, and even 470 in some cases .... and being cathode biased, you would really subject these gems to a short life at the HV setting.

Thanks Myles- as always it's very much appreciated! I felt there was something good about them when I plugged them in. Thanks for the tip on the Univalve setting, I would have run them on HiV and burnt them out too quickly without your help.

[Feel free to ask Myles]

Myles!

 

I got lucky and scored these 60's tubes that some guy pulled from a Fender amp and sold them to me on Ebay.

Paid what one retail Russian 6L6 goes for over here.

 

Anyway, I really dig the one on the right- it's like a super-charged 6V6.

I can crank the Univalve to 10 with HiV and there's no grit at all, just nice smokey crunch and distortion.

They all sound really great though.

Too bad the Italian postal service broke one .

 

All the way on the left:

Smokey glass, etching says "6L6 G FIVRE 206" and sticker says "Fivre 6VS"

 

Middle:

Clear glass, etching says "6L6 G FIVRE 206" and sticker also says sticker says "Fivre 6VS"

 

On the Right (MY FAV!):

No printing or stickers except on the top of the tube there are 2 sets of numbers "333 306"

http://www.jameskettner.com/Tubes/NewTubes.JPG

 

Did I score some cool tubes? Can you tell me anything about them?

Can I run the one all the way on the right on HiV without problems?

[Feel free to ask Myles]

Bump for Otto.

[Feel free to ask Myles]

Myles,

In the Univalve- when I run an EL84 with the YellowJacket, do I have to run it "ONLY" in LoV like the 6V6's?

 

Will the Mazda 6V6 I just got blow if I run them in HiV? (don't want to risk it without checking with you, but if they will hold up to 465+ plate volts you said... maybe HiV will render a different sound)

 

Thanks!

[Feel free to ask Myles]

Myles.....

 

I don't even know where to start. To think that last October when I stumbled over this forum I knew very little about amps, and even less about tubes.

 

You've turned me on to the THD Univalve which is the best guitar tool around. I just don't understand how anyone who can afford one doesn't have one. To be able to use different tubes and completely change the sound of the amp in 15 seconds is incredible. With the Univalve I've discovered sounds I've only dreamed of attaining. Used as a pre-amp into a great head the possibilities are endless. The Univalve must be the most underrated amp in existance.

 

You are really a great guy to help all of us here on the forum. I can't thank you enough.

 

Three Cheers for Myles!!!!

[Feel free to ask Myles]

Originally posted by myles111:

The new JTM-45's use 5881's (as did some of the originals in the old days, and others used KT-66's.)

 

The "ECC83" marked tubes in many Marshall amps these days are not ECC83 tubes, but 12AX7 tubes which I have seen with "ECC83 Marshall" screening. They are of various 12AX7 makes.

 

The JJ short plate ECC83 is a real ECC83, and this is what I would use.

 

Watford Valves in the UK is a GREAT tube supplier. Their JJ ECC83's would be great. Their Harma KT-66 tubes are of the Chinese variant, which do not have the curves of the GEC tubes (or the KT-66HP), but will be nice enough.

 

If you want the KT-66HP, in Europe, then just contact

 

Groove Tubes Europe c/o Guitar XS Ltd. - Doug Chandler or Tina Shapre

Thomas Point 12a Waterside

Upper Brents, Faversham, Kent, ME13 7AU

Kent, Email: Doug@guitarXS.com

Phone: +44 (0)1795 538877

Fax: +44 (0)1795 538877

 

or ............. if you want them in Italy,

any of the GT products (as the KT-66HP is a GT built tube and not sold by others)

 

MCAS / M. Casale Bauer S.P.A.

Via IV Novembre, 6/8

40057 Cadriano di Granarolo

(Bo), P. IVA 00542121207, Email: info@casalebauer.com

Phone: 39 051 7666

Fax: 39 051 7660

 

These folks would also have the ECC83's.

Thanks Myles!

 

I ordered 11 tubes today from Watford, but waited on the JTM45 replacements till I heard from you. Glad I did! I'll track down some (non Chinese) KT66's at the places you listed above.

 

Today from Watford I ordered (for the Univalve):

2x 6L6GC Harma STR

2x ECC82/12AUTWA R.T.

2x ECC83/ECC83S JJ Tesla

2x ECC81/12AT7WC Phillips

1x EL84 Harma STR

1x 6V6GT RCA (supposed to be really good)

1x 6V6GT Mazda (can you tell I like the 6V6's?)

 

Separatley I ordered a YellowJacket so I can use the EL84 in the Univalve.

 

Thank again Myles- you are the man!

[Feel free to ask Myles]

Originally posted by myles111:

Originally posted by Chipotle:

Myles, I read your review of the Ruby Tubes EL34B-STR and thought I might try either a pair of those or a pair of the GTKT66 HP's in this JTM45 type thing. I was thinking a #4 rating for the KT66's, but how does one specify an equivalent power rating for the Ruby tubes? I was planning on buying from Antique Electronic Supply who do some type of matching for $1 per tube.

Chipotle .............

 

In a JTM-45, to my thinking, the KT66HP is the only way to go. It was the original tube.

 

If your amp has about 400 B+ and a GZ34 rectifier, get these in a #6, and bias at 36mA (some may say bias higher, but then the amp gets a bit harsh at some settings). Make sure V1-V3 are ECC83 and not 12AX7 or 7025 tubes (ECC83's were original and do sound different), and make sure V3 is a matched phase inverter, and not just matched for gain, but matched for rise time also, as in these amps, it is one piece of the magic.

Myles,

Found this old post regarding the JTM45. I just bought one new that has the 2x5881 and 3xECC83. I like the sound now, but know what good tubes can do (ala THD Univalve). I was going to order from Watford (which is the best for me here in Italy- no customs or duties to pay). Just wanted to check with you first since you're the expert!

2xKT66 Harma

3xECC83 JJ Tesla

GZ34 Sovtek Rectifier (a GZ34 is in the JTM, but don't know what make)

 

Will I notice an improvement?

Do I have to do anything besides Re-bias?

 

Thanks Myles- You Rock!

[Feel free to ask Myles]

Originally posted by myles111:

Where did you find GT 6V6NOS tubes? We don't even sell those anymore, they are kept for personal stash.

 

The 12AX7EH is a good tube, but the 12AT7EH can have some issues in cathode follower tone circuits in some amps.

 

If you run a 6V6 in high voltage in the UV, you will destroy it. This is a class A amp, and 450 plate volts, even in A/B is a killer on these tubes.

 

Tubes like current, not voltage.

 

Your UV tube on the left, facing the amp, is V1.

Thanks Myles! Guess they've probably been laying around my local music store for a while now. I'll go back on Saturday and see if they've got anymore. I think I paid @$20 (hard to tell cause it was mixed in with the Les Paul), but I think I'm a pretty good customer. I also had them order the THD UV for me so they know why I want them.

 

I'd heartily support Guitplayer as a Mod fwiw.

[Feel free to ask Myles]

Myles, I posted this in the "Tube Primer" thread since it was continuing my discussion with Guitplayer. I posted it here also because it's a true Ask Myles post!

 

Armed with Myles's Tube Primer in hand I was able to discuss tubes with the guitar-shop guy like I knew what I was talking about! Guitplayer, I followed your advice and bought what we said yesterday.

 

GT6V6"NOS"

12AX7 (EH?) for the V1

12AT7 (EH?) for the V2

 

Myles, do you think I need to run the Univalve in LoV as Guitplayer suggested? Is it gonna hurt if I run it in HiV?

I read in your primer that the 6V6 holds up well to 450+ volts on the plate. The Univalve manual states that HiV applies @450-470v (depending on the tube) and @300-320v on LoV.

 

Photo of the tubes

 

Edit: When I installed them today the Univalve has written on it the warning (like Guitplayer said) to only run 6V6 in LoV. So that settles that. There's more than enough crunch with LoV I found.

 

Instead I have another question. On the Univalve the Pre-amp tubes are labeled Input and Drive. Which is V1 and which is V2? I installed the AX7 in Input and the AT7 in drive. Is that good?

[Feel free to ask Myles]

Thanks Myles. I'm in Italy so Ebay is out for me. Luckily however, I'm coming to the states to visit the parents at Christmas. I'll go ahead and order a set from you anyway using my Mom's address and bring them back in a suitcase. Unless we can figure out some way to get them to Italy without paying 3 times the value at customs...

 

How much space do 10 tubes take up? I think I can fit them in a suitcase without the wife having a cow... Should I contact you by Email to special order a package for the sounds I'm looking for, or does the big set include it all?

[Feel free to ask Myles]

Hi Myles,

 

I ordered the THD Univalve a few weeks ago after reading your comments and on the advice of some of the guys on this forum. It should be here next week... not many units get to Italy and it takes a while. I'm trying to digest the info on your site about tubes now that I'm getting this puppy. I'm sure I'll be back with some questions once I'm playing around with it.

 

My immediate problem is to make the

Marshall TSL122 amp work with the

Marshall SE100 attenuator/Cab simulator

without blowing anything.

 

It came to me when I ordered the THD to buy a powerbrake for the Marshall, but the local store didn't have any. They offered me a used SE100 for the equivalent of @$95. From what I've found on the net this is a great deal on an excellent piece of equipment. I'm scared of blowing something up though.

 

The TSL has 16ohm speakerout which plugs into the cab. It also has a switchable 4/8ohm out. The SE100 has a 8ohm Speakerin (from amp) and an undisclosed ohm speaker out (to cab). Do I plug the TSL 8ohm out into the 8ohm in on the SE100, then the Speakerout to the 2x12 Cab in the TSL? I figure the speakers are 16ohm and my gut tells me it's ok to configure like above. But my head tells me to be careful before I blow something. Any help would be greatly appreciated.

 

I don't like the VPR switch on the TSL122 which reduces it from a 100w to a 25w amp. I really do like the LineOut from the SE100 to my Mixer, but I only use the mixer in my basement studio. (I live on the 4th floor and play mostly in my apartment.)

 

Thanks in advance if you can help me. Even if you can't- Thanks a million for all your info, help, and time.

 

CIAO!

[Feel free to ask Myles]

Don't really have a question- just wanted to say

 

"Myles you are an Amp GOD!!!"

 

Too cool the way you help guys out. And your website went immediately in my bookmarks. Since gtrmac just recommended the THD Univalve (and it took me about 10 minutes of research on the web to decide to get one), I'm sure I'll be referencing your site a bit.