Feel free to ask Myles

[myles_rose]

Originally posted by Teahead:

Hey Myles, just wondering if you wouldn't mind checking a question I posed on the "Tech tip for EL84 based amplifiers" thread. I'd post you a link but I'm afraid I don't know how, maybe I'll bump it to bring it back onto the first page.

Thanks for your help, Tea.

Tea ....

 

Just answered that post over there for you.

[Teahead]

Thanks Myles, but I had the audacity to ask yet another question on that thread(!) Sorry to trouble you again, I respect your opinion on this subject and I'm keen to get the best sound I can from my amp. Thanks again for your time, Tea.

[rsf1977]

Hey Myles, I just heard about pitting KT66s ib Mesa Dual Rects.

 

1) I was wondering what your opinion was on that

2) what are the tonal differences between KT66s and 6L6s

3) how would you set the bias to 6L6 or EL34

[myles_rose]

Originally posted by Teahead:

Thanks Myles, but I had the audacity to ask yet another question on that thread(!) Sorry to trouble you again, I respect your opinion on this subject and I'm keen to get the best sound I can from my amp. Thanks again for your time, Tea.

Tea ....

 

No problem.

 

There is no charge on the number of questions

[myles_rose]

Originally posted by rsf1977:

Hey Myles, I just heard about pitting KT66s ib Mesa Dual Rects.

 

1) I was wondering what your opinion was on that

2) what are the tonal differences between KT66s and 6L6s

3) how would you set the bias to 6L6 or EL34

rsf1977 .........

 

These work great in the Mesa, and folks are now using them a lot in the Soldano amps too.

 

More mids, smoother, more balls all around. A very big sounding tube.

 

BUT ... a few things to note in the Mesa ...

 

1. DO NOT USE KT66C tubes. They only can safely take 450 or so plate volts.

 

2. USE ONLY a KT66HP, which can go over 525 with ease.

 

3. Bias as close to 30mA as possible in your amp. This means using the 6L6 setting, as the EL34 setting will blow them or burn them up pretty fast.

 

4. USE a rating of "6" on the HPs in the Mesa. This is the same current range as the Mesa Blue and White rating in the Mesa 6L6 tubes, and will bring the bias to a proper range, and not run as cold as a Mesa 6L6 runs in the 6L6 setting.

[aeon]

Myles...three questions:

 

1. do you have any online soundclips of the Victoria Sovereign?

 

2. have you tried running the Sovereign with a pair of THD Yellowjackets?

 

3. given the quality of new EF86 valves, I assume that NOS is the only way to go for V1...it seems that so much of the amp is built around the unique characteristics of the EF86, but have you tried it with the new GT EF86/12AX7 socket replacer?

 

thanks,

aeon

[myles_rose]

Originally posted by aeon:

Myles...three questions:

 

1. do you have any online soundclips of the Victoria Sovereign?

 

2. have you tried running the Sovereign with a pair of THD Yellowjackets?

 

3. given the quality of new EF86 valves, I assume that NOS is the only way to go for V1...it seems that so much of the amp is built around the unique characteristics of the EF86, but have you tried it with the new GT EF86/12AX7 socket replacer?

 

thanks,

aeon

aeon .......

 

1. do you have any online soundclips of the Victoria Sovereign? ..........

 

..... nope. I really hate clips. It is sort of like taking a test drive from the back seat of the car ... the recording techinques are not known, but most of all, you cannot feel how the amp reacts to touch. This is why some folks think there is a bigger difference between modelling amps and their target model. The touch and feel aspect is different. That is also why a plexi Marshall is so much more articulate and magincal than the later high gain models even when the high gain ones are run at lower levels.

 

2. have you tried running the Sovereign with a pair of THD Yellowjackets?

 

......... Yes and no .... GT has their own PR928 (the same idea as the Yellow Jacket). Remember, Red Rhodes (long gone now), was the guy that first made these things up, and that is where THD learned about them about 20 years ago. I have used the PR928's and they work fine in the Sovereign.

 

3. given the quality of new EF86 valves, I assume that NOS is the only way to go for V1...it seems that so much of the amp is built around the unique characteristics of the EF86, but have you tried it with the new GT EF86/12AX7 socket replacer?

 

........... You don't need NOS, you just need an EF86 that meets original specs, which the vast majority do not. A good EF86 is a long lasting tube, so I have some of these in my own inventory for the Sovereign and Dr Z amps, as well as some of my Vox clients. I hand pick these by the way for Dr. Z for his production of the Z28, Route 66, and KT-45 now. I will be doing the same for Mark Baier at Victoria. You would always be able to get replacements from Mark at Victoria or from GT.

 

I have used the EF86 adaptor. I think having one of these if you have a few Matchless DC-30s on tour would be a great insurance idea, as loosing an EF86 in these amps and you are out of luck. They make the amp work, and in the Matchless and Bad Cat amps, they are pretty cool, although the sound is different ... but some folks love it more ... some less.

 

In the Sovereign, I do not like it, but that is my personal take, and since I work for GT, I have to say again, this is my personal view, and not the view or taste perhaps of other GT folks.

 

In a Dr Z amp, I also do not like it. I prefer the real EF86.

 

Part of the reason for this I guess, is that in the Matchless and Bad Cat, the EF86 is used for their high gain channel. It was also designed by Mark Sampson, so there is a good reason it works nicer with "his" amps.

 

On the Victoria and Z amps, the EF86 is used as a great pentode for great response, headroom, and gain too, but not in as gainy of a way. The EF86 was used in the greatest (to my thinking anyway) of the Vox AC-10, AC-15, and early AC30 amps. So ...... in the V and Z amps, changing the tonal character with the dual triode to pentode adaptor, colors thing in a way that I do not like personally. Who knows, some folks may totally think I am full of crap, but this is my view. The V (Victoria) and Z amps, from the builder, sound and play about as magical as any amps around. So ... since I love them the way they are, I do not like the adaptor.

[Major Tom]

I have an old Peavey Bravo - 2xEL84 1x12 combo. I have made a few minor mods to it and changed the speaker - it is a killer little amp now. Anyway, I just put some new sovtek El 84's in, and 1 crapped out after a couple hours, which prompted me to look into it a little. I measure 385 volts at the plate, and from everything I read, this is higher than the norm. I am going to install a standby switch this weekend. A few questions, thanks in advance for any help.

1) should I decrease the B+ with a couple or 3 zener diodes in series with the bridge rectifier to bring it into the 350 volt range?

2) will letting the tubes warm up for a minute before flipping the standby on really help prevent tube failure and extend their life?.

3) I didn't measure the B++ or other B+ "derivative" voltages for the preamp tubes, but will lowering the supply voltage by 35 volts have an ill effect of them? - what is the accepted voltage range for them?

4) I haven't checked the bias on this amp (no adjustment pot) - Peavey shows -18v on the schematic - does that sound right? I have seen -12v listed for EL84's elsewhere...

5) will lowering the B+ by 35 volts necessitate a re-bias, or cause the tubes to draw excessive current?

[myles_rose]

Originally posted by Major Tom:

I have an old Peavey Bravo - 2xEL84 1x12 combo. I have made a few minor mods to it and changed the speaker - it is a killer little amp now. Anyway, I just put some new sovtek El 84's in, and 1 crapped out after a couple hours, which prompted me to look into it a little. I measure 385 volts at the plate, and from everything I read, this is higher than the norm. I am going to install a standby switch this weekend. A few questions, thanks in advance for any help.

1) should I decrease the B+ with a couple or 3 zener diodes in series with the bridge rectifier to bring it into the 350 volt range?

2) will letting the tubes warm up for a minute before flipping the standby on really help prevent tube failure and extend their life?.

3) I didn't measure the B++ or other B+ "derivative" voltages for the preamp tubes, but will lowering the supply voltage by 35 volts have an ill effect of them? - what is the accepted voltage range for them?

4) I haven't checked the bias on this amp (no adjustment pot) - Peavey shows -18v on the schematic - does that sound right? I have seen -12v listed for EL84's elsewhere...

5) will lowering the B+ by 35 volts necessitate a re-bias, or cause the tubes to draw excessive current?

Major .....

 

The Sovtek EL84s are generally not the way to go in your amp sonically, or at least not from my point of view.

 

I also do not know where the tubes came from, and the chances are they have a static draw that may not be what your amp expects.

 

In any case, before playing B+ games, get a good set of JJ EL84 tubes, in a #5 rating if from GT, as these will work great and there is a big chance your problem will be gone, and your tone will also improve.

 

Your plate voltage is not out of line ... many current EL84 amps run plate voltages way above the 350 volt spec max. It is the screen current that kills these most often.

[Major Tom]

Thanks for your help, I have heard a lot of good reviews of the JJ's - I will get a couple sets of the #5. I was using the Sovteks 'cause they are what came in the amp and are inexpensive, but not so cheap when you gotta replace 'em....

[myles_rose]

Originally posted by Major Tom:

Thanks for your help, I have heard a lot of good reviews of the JJ's - I will get a couple sets of the #5. I was using the Sovteks 'cause they are what came in the amp and are inexpensive, but not so cheap when you gotta replace 'em....

Tom,

 

You are more than welcome.

 

Keep in mind that a JJ E34L is not the same tube or plate structure as the JJ factory GT tooling E34LS. The JJ is a 25 watt tube and the LS is a 30 watter.

 

They bias very differently.

[daddyelmis]

Myles . . . looking for your opinion on aftermarket point-to-point boards for reissues (in my case, a 59 Bassman RI).

 

On the one hand, companies got away from ptp to avoid the errors introduced by having a roomfull of different schmoes hand soldering 100's of connections. In addition, my logical mind tells me that electrons flowing through the "same" circuit should behave the same, whether it's traces and surface mount components or ptp.

 

On the other hand, you'd think ptp boards were the Holy Grail to see their prices and to hear folks talk about them.

 

I want to get a bias pot installed on the Bassman RI, and I'm thinking that I might just spring for the PTP while I'm at it (I've been emailing the guys at ceriatone about a 5F6-A board).

 

Whaddya think? Hype? Reality? More G.A.S.???

 

Your opinion is, as always, highly valued.

[cincinnatirock]

I did a search of the forums and was wondering if a 6550 tube could be used as a substitute for either a 6L6 or an EL34. I need all the extra headroom I can get.

[myles_rose]

Originally posted by daddyelmis:

Myles . . . looking for your opinion on aftermarket point-to-point boards for reissues (in my case, a 59 Bassman RI).

 

On the one hand, companies got away from ptp to avoid the errors introduced by having a roomfull of different schmoes hand soldering 100's of connections. In addition, my logical mind tells me that electrons flowing through the "same" circuit should behave the same, whether it's traces and surface mount components or ptp.

 

On the other hand, you'd think ptp boards were the Holy Grail to see their prices and to hear folks talk about them.

 

I want to get a bias pot installed on the Bassman RI, and I'm thinking that I might just spring for the PTP while I'm at it (I've been emailing the guys at ceriatone about a 5F6-A board).

 

Whaddya think? Hype? Reality? More G.A.S.???

 

Your opinion is, as always, highly valued.

daddyelmis .............

 

The biggest issue with your RI Bassman is not the board, it is that they come stock with a 12AX7 in V1 rather than the original 12AY7, and a solid state rectifier which is thankfully in a socket, so a 5AR4 can be used.

 

This is the first step in the right direction, to change these two things ... fast and cheap.

 

As far as PTP vs PCB, I have a lot of info on my website in my tech tips, some great stuff written by Andy Marshall from THD.

[myles_rose]

Originally posted by cincinnatirock:

I did a search of the forums and was wondering if a 6550 tube could be used as a substitute for either a 6L6 or an EL34. I need all the extra headroom I can get.

cincinnatirock.......

 

Generally, yes. Look on my website.

[Gabriel E.]

Not a question this time - just bragging.

 

Bought a box of tubes at a Salvation Army auction the other day for $25. Most were RCA tubes for B&W TVs.

 

However:

 

1-Mullard 12AX7

 

1-Ratheon 5U4GB

 

1-RCA 12AU7

 

1-RCA 5R4GYB

 

1-Amperex EF86

 

1-Mullard 5AR4/GZ34 with a metal base.

 

All in unused condition.

 

Put the RCA 12AU7 and the Mullard 5AR4 in my tweed Super and it sounds incredible. Need to rebias though cuz the plates on the output tubes started glowing.

 

A bunch of the RCA tubes were rebranded "Curtis Mathers". Know anything about these?

[Mudcat]

Myles,

Really appreciate all of the help you provide to the forum. Now it's my turn to pick your brain. I have a Musicman RP112 that has never (to my knowledge) been serviced. Is there anything that can be done with this thing? It sounds brittle to my ears and I would like to smooth it out a bit. I don't know if this is because of the SS preamp section or because of age coupled with a lack of maintenance.

 

Thanks in advance!

[Guitar Geezer]

Curtis Mathes used to be one of the more prestigious TV Manufacturers (back when they ran on "tubes". Their motto was something like "The most expensive set in America...and darn well worth it"

.

.

So i guess that's where they came from!

[Blue Strat]

Originally posted by Gabriel E.:

A bunch of the RCA tubes were rebranded "Curtis Mathers". Know anything about these?

Nice score! Re-branding tubes was a common practice in the days when most commercial products used them. Curtis Mathis is a TV company. If they're RCA's they're still excellent tubes. Willing to sell any? Could you post a complete list or PM me? I'd be particularly interested in any 6BQ5, 6AQ5, 6AV6, 6SN7, 6CG7, 6SL7, or 6AU6 tubes you're willing to part with.

[Gabriel E.]

Thanks for the responses guys. Interesting about Curtis Mathis. Never seen one of those TVs around.

 

Bluestrat, I'll PM you a list this evening or tomorrow.

 

Gabriel

[daddyelmis]

Originally posted by myles111:

Originally posted by daddyelmis:

Myles . . . looking for your opinion on aftermarket point-to-point boards for reissues (in my case, a 59 Bassman RI).

 

On the one hand, companies got away from ptp to avoid the errors introduced by having a roomfull of different schmoes hand soldering 100's of connections. In addition, my logical mind tells me that electrons flowing through the "same" circuit should behave the same, whether it's traces and surface mount components or ptp.

 

On the other hand, you'd think ptp boards were the Holy Grail to see their prices and to hear folks talk about them.

 

I want to get a bias pot installed on the Bassman RI, and I'm thinking that I might just spring for the PTP while I'm at it (I've been emailing the guys at ceriatone about a 5F6-A board).

 

Whaddya think? Hype? Reality? More G.A.S.???

 

Your opinion is, as always, highly valued.

daddyelmis .............

 

The biggest issue with your RI Bassman is not the board, it is that they come stock with a 12AX7 in V1 rather than the original 12AY7, and a solid state rectifier which is thankfully in a socket, so a 5AR4 can be used.

 

This is the first step in the right direction, to change these two things ... fast and cheap.

 

As far as PTP vs PCB, I have a lot of info on my website in my tech tips, some great stuff written by Andy Marshall from THD.

Thanks, Myles, I'll check out the web info. Based on your earlier advice I already made the tube switches for V1 and the rectifier.

[myles_rose]

Originally posted by Mudcat:

Myles,

Really appreciate all of the help you provide to the forum. Now it's my turn to pick your brain. I have a Musicman RP112 that has never (to my knowledge) been serviced. Is there anything that can be done with this thing? It sounds brittle to my ears and I would like to smooth it out a bit. I don't know if this is because of the SS preamp section or because of age coupled with a lack of maintenance.

 

Thanks in advance!

Mudcat ............

 

These are killer great amps.

 

We have about 1/2 a dozen Music Man amps that are loaned out on tour to replace the "great" amps that die on the road trips from city to city.

 

The big deal here is output tubes, as these run very high plate voltages.

 

Make sure you have fresh output tubes and the amp is biased properly. Improper bias set too low (so the amp runs hot and harsh) is the big culprit.

[myles_rose]

Originally posted by Gabriel E.:

Thanks for the responses guys. Interesting about Curtis Mathis. Never seen one of those TVs around.

 

Bluestrat, I'll PM you a list this evening or tomorrow.

 

Gabriel

Gabriel,

 

They also made killer Hi Fi gear.

[myles_rose]

Originally posted by daddyelmis:

Originally posted by myles111:

Originally posted by daddyelmis:

Myles . . . looking for your opinion on aftermarket point-to-point boards for reissues (in my case, a 59 Bassman RI).

 

On the one hand, companies got away from ptp to avoid the errors introduced by having a roomfull of different schmoes hand soldering 100's of connections. In addition, my logical mind tells me that electrons flowing through the "same" circuit should behave the same, whether it's traces and surface mount components or ptp.

 

On the other hand, you'd think ptp boards were the Holy Grail to see their prices and to hear folks talk about them.

 

I want to get a bias pot installed on the Bassman RI, and I'm thinking that I might just spring for the PTP while I'm at it (I've been emailing the guys at ceriatone about a 5F6-A board).

 

Whaddya think? Hype? Reality? More G.A.S.???

 

Your opinion is, as always, highly valued.

daddyelmis .............

 

The biggest issue with your RI Bassman is not the board, it is that they come stock with a 12AX7 in V1 rather than the original 12AY7, and a solid state rectifier which is thankfully in a socket, so a 5AR4 can be used.

 

This is the first step in the right direction, to change these two things ... fast and cheap.

 

As far as PTP vs PCB, I have a lot of info on my website in my tech tips, some great stuff written by Andy Marshall from THD.

Thanks, Myles, I'll check out the web info. Based on your earlier advice I already made the tube switches for V1 and the rectifier.

daddyelmis ...........

 

If you need any help, just drop me a note.

[Mudcat]

Originally posted by myles111:

Originally posted by Mudcat:

Myles,

Really appreciate all of the help you provide to the forum. Now it's my turn to pick your brain. I have a Musicman RP112 that has never (to my knowledge) been serviced. Is there anything that can be done with this thing? It sounds brittle to my ears and I would like to smooth it out a bit. I don't know if this is because of the SS preamp section or because of age coupled with a lack of maintenance.

 

Thanks in advance!

Mudcat ............

 

These are killer great amps.

 

We have about 1/2 a dozen Music Man amps that are loaned out on tour to replace the "great" amps that die on the road trips from city to city.

 

The big deal here is output tubes, as these run very high plate voltages.

 

Make sure you have fresh output tubes and the amp is biased properly. Improper bias set too low (so the amp runs hot and harsh) is the big culprit.

Thanks! I may get back to you on tube selection for the sound I'm looking for.

[myles_rose]

Originally posted by Mudcat:

Originally posted by myles111:

Originally posted by Mudcat:

Myles,

Really appreciate all of the help you provide to the forum. Now it's my turn to pick your brain. I have a Musicman RP112 that has never (to my knowledge) been serviced. Is there anything that can be done with this thing? It sounds brittle to my ears and I would like to smooth it out a bit. I don't know if this is because of the SS preamp section or because of age coupled with a lack of maintenance.

 

Thanks in advance!

Mudcat ............

 

These are killer great amps.

 

We have about 1/2 a dozen Music Man amps that are loaned out on tour to replace the "great" amps that die on the road trips from city to city.

 

The big deal here is output tubes, as these run very high plate voltages.

 

Make sure you have fresh output tubes and the amp is biased properly. Improper bias set too low (so the amp runs hot and harsh) is the big culprit.

Thanks! I may get back to you on tube selection for the sound I'm looking for.

Mudcat.................

 

You are more than welcome.

[jzgtrguy]

posted 11-26-2003 01:08 PM

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

Myles,

 

Sorry about emailing you direct. I am new to this forum, I followed the link from your website.

 

I had emailed asking advice about buying an amp to play Fusion and Rock. I have been hunting at EBAY and seen these amps that interested me.

 

Rivera Fandango or Quiana

Pro Tube Pro Reverb

Groove Tubes Soul-O 75

Gerlitz Revolator

Randall MTS 50 Watt Combo

 

I know that covers a lot of sonic territory and any one of these amps would probably sound great in the right hands. So what am I really asking for? I just wanted to avail myself to your expertise on Reliability and which ones had the most versitility (great clean sound and a great distortion). I went down to Guitar Trader and played a Pro Reverb and the clean was nice but the dirty channel sounded a little harsh. Unfortunately I could not turn it up. I have not tried the others.

 

I am not looking to emulate anyone elses tone but I like to listen to Pat Metheny, Erich Johnson, Frank Gambale, Allan Holdsworth and so on.

 

Is there anywhere I could listen to almost all of these amps at once?

 

Thanks in Advance,

 

Best,

 

Jeff

[jzgtrguy]

Myles,

 

Sorry for this little addition but I thought it might be improtant.

 

My main electric guitar is a 1972 Les Paul Model with Seymnours in it a Jazz in the neck and a JB in the bridge.

 

My main Jazz guitar (the one I live on) is a Comins Concert Model with a custom Fralin pickup derived from an Unbucker.

 

That might help shed some light on which amp.

 

Out,

 

Jeff

[myles_rose]

Originally posted by jzgtrguy:

posted 11-26-2003 01:08 PM

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

Myles,

 

Sorry about emailing you direct. I am new to this forum, I followed the link from your website.

 

I had emailed asking advice about buying an amp to play Fusion and Rock. I have been hunting at EBAY and seen these amps that interested me.

 

Rivera Fandango or Quiana

Pro Tube Pro Reverb

Groove Tubes Soul-O 75

Gerlitz Revolator

Randall MTS 50 Watt Combo

 

I know that covers a lot of sonic territory and any one of these amps would probably sound great in the right hands. So what am I really asking for? I just wanted to avail myself to your expertise on Reliability and which ones had the most versitility (great clean sound and a great distortion). I went down to Guitar Trader and played a Pro Reverb and the clean was nice but the dirty channel sounded a little harsh. Unfortunately I could not turn it up. I have not tried the others.

 

I am not looking to emulate anyone elses tone but I like to listen to Pat Metheny, Erich Johnson, Frank Gambale, Allan Holdsworth and so on.

 

Is there anywhere I could listen to almost all of these amps at once?

 

Thanks in Advance,

 

Best,

 

Jeff

Jeff ..........

 

Rivera Fandango or Quiana - The Quina with it's 6L6 output stage, with a set of KT66HP's in a #5 at the stock bias rating is killer.

 

Pro Tube Pro Reverb - This is a good amp, but for what you are looking for, from my point of view, the clean would be too clean, and with no Master Volume on the clean channel, you could not control the front end compression as you could on the Rivera. The gain channel is too limited in scope for your use.

 

Groove Tubes Soul-O 75 - great amps, but too heavy and loud with a sweet spot that is a very high level.

 

Gerlitz Revolator - I know nothing about this amp.

 

Randall MTS 50 Watt Combo - complex front end that would have too little articulation for your

needs from my personal point of view.

 

On the aspect of reliability, the Rivera amps I support, have never had one single minute of downtime due to the amp's design or construction.

 

You can listen to a lot of these amps at True Tone Music in Santa Monica. I am sure there are other places, but off the top of my head I can not think of any.

[myles_rose]

Originally posted by jzgtrguy:

Myles,

 

Sorry for this little addition but I thought it might be improtant.

 

My main electric guitar is a 1972 Les Paul Model with Seymnours in it a Jazz in the neck and a JB in the bridge.

 

My main Jazz guitar (the one I live on) is a Comins Concert Model with a custom Fralin pickup derived from an Unbucker.

 

That might help shed some light on which amp.

 

Out,

 

Jeff

Jeff ....

 

Still the Rivera.