Feel free to ask Myles

[myles_rose]

Originally posted by otto:

Originally posted by myles111:

Originally posted by otto:

Ruuning too high of ID in a Marshall will make the amp too clean, or at least it will not sound like a great Marshall. You need to have some crossover notch.

 

Thank you Myles, but are you saying that in a Marshall it is good to set the bias to have less than 50% of power at idle?

You actually want to set is at about 55% or so, and that would depend on your plate voltage. All amps are a bit difference. On Marshalls, it is actually better to set them with a scope looking at the crossover notch.

 

If you are ever near Los Angeles, I would be happy to do this for you for free.

Thank for your replies Myles, you are very kind. I would like to come to LA, but I am from Italy.

Your site is very good, thank you, but I did not find the answer to my doubt.

My JCM 800 4210 (50 W, split channel) has 450 V of plate voltage. I read that bias at idle must be set to have maximum 70% of power at idle, minimum 50%.

I understood that near 70% you obtain more distortion, near 50% more clean, is it not right?

You suggest to me 55%?

Otto.....

 

With 25 watt EL-34 tubes:

 

50% 60% 70%

 

28 33 39

 

With 30 watt E34LS tubes:

 

50% 60% 70%

 

33 40 47

 

Make sure your plate voltage is really 450, do not trust the prints or specs. Test fully loaded, not with a tube pulled. As current and idle dissapation is raised, plate voltage will drop, so keep this in mind.

 

Cooler tubes lack power and are grainy.

 

Hotter tubes are harsh and also have short life.

 

It may be better if you want to dial in very close, to figure at what volume amp setting you want the amp to sound best, and bias around that point with a scope, load, and 1Khz signal in the case of a Marshall.

[Dave da Dude]

Myles,

 

I'm looking for your (very learned) OPINION here.

 

Do you think that (in general) the new Pre-Amp tubes are on a par with NOS tubes yet?

 

In other words, is it worth the premium to buy NOS tubes?

 

Dave

[Chris Hebb]

Myles,

I saw on your website that you have a Rivera Sub 1 in your personal collection. How do you like it and how well does it compliment a 1x12 combo amp? Or would my money be better spent on a regular 2x12 external cabinet?

[michael saulnier]

Originally posted by myles111:

Originally posted by Ziggy:

Myles,

 

This is the third question I've posted here and let me first say thanks for the assistance you've provided.

 

I have a question concerning setting up a pre-amp stage. I'm sure this is a dumb question, but I'll ask anyway. I have a Pro-Jr. which as you know only has a tone and volume knob. Is it possible to take the output of another tube amp and plug it into the input of my Pro-Jr. in order to set up a pre-amp stage? I'm thinking that the output of another amp is probably the wrong type of signal and would damage my Jr., but I wanted to check because it would be nice to get some tube distortion at a low volume if possible.

 

Thanks in advance,

Ziggy

Ziggy..............

 

You cannot do this. Your amp's input is expecting a very low level signal at very high impedance. This will damage both amps.

Except of course, if you have a THD UniValve that is DESIGNED to do exactly this with a proper impedence output in addition to the regular speaker out...

 

A UniValve works GREAT for this!

 

guitplayer

[myles_rose]

Originally posted by Dave th Dude:

Myles,

 

I'm looking for your (very learned) OPINION here.

 

Do you think that (in general) the new Pre-Amp tubes are on a par with NOS tubes yet?

 

In other words, is it worth the premium to buy NOS tubes?

 

Dave

Dave,

 

Many NOS tubes today are going down in quality, as they are pulls in cases, and sold as new, or have been bounced around warehouses for years. The 1987 JAN Philips AT7s were fine but the 1988s I recently tested in bulk were almost useless.

 

New tubes are getting better all the time. The Chinese 12AX7C9 (9th generation tooling) are closer to spec and have tighter QA tolerances than most of the Mullards, Telefunkens, and many other high end tubes from the past that are left around these days. BUT ... all tube designs sound different, so this is also a factor.

 

There are not all than many NOS vendors I trust. Places like Upscale Audio, KCA NOS, Doug Preston, Vacuum Tube Valley, are some of the few that I trust and personally use.

 

The 12AX7EH by Electro Harmonix is very close to the 12AX7C9 in quality, but does sound a bit different ... it is personal taste. This EG tube is also known as the GT 12AX7R3 sold by GT and more highly tested.

 

All the specs on all of these are in my tube primer book off my website (get it for free as my guest from this Forum). There are also NOS specs there too.

[myles_rose]

Originally posted by Chris Hebb:

Myles,

I saw on your website that you have a Rivera Sub 1 in your personal collection. How do you like it and how well does it compliment a 1x12 combo amp? Or would my money be better spent on a regular 2x12 external cabinet?

Chris,

 

I so not use the Sub 1. It is for clients and folks that do dropped tunings, or if used with the internal crossover, then your amp does not have to produce frequencies of under 100hz, so you have huge amp power and headroom.

 

If I were not 54, and were at least two decades younger, and a heavy player, I would not play without it. But ... I am an old blues and acid rock sort of old fart, stuck in music styles that were around before cool stuff like subs were invented for guitar players

[johnny5]

myles,

i know this question keeps coming up, but ths is the last time i'll ask. i believe you are familiar with the peavey classic series (classic 30, delta blues, etc.).

 

is the Carme Ghia as loud or louder than the classic 30 or delta blues? (or should i say "have the abilty to cut as well"). i am about to order a Ghia and have a C30. the C30 "just" hangs with the band, so anthing there or beyond is ok.

 

thanks,

john

[myles_rose]

Originally posted by johnny5:

myles,

i know this question keeps coming up, but ths is the last time i'll ask. i believe you are familiar with the peavey classic series (classic 30, delta blues, etc.).

 

is the Carme Ghia as loud or louder than the classic 30 or delta blues? (or should i say "have the abilty to cut as well"). i am about to order a Ghia and have a C30. the C30 "just" hangs with the band, so anthing there or beyond is ok.

 

thanks,

john

John,

 

Go otu and try tp play a Carmen Ghia. It is a very loud amp, maybe about the same as your Peavey, but with different harmonic content, so it may seem even louder.

 

This is one of those "you gotta hear it for yourself" sort of deals ... and speakers and cabs make an even bigger difference.

[daddyelmis]

Myles:

 

Can bridging inputs hurt an amp? I've got a 59 Bassman RI and some guy was talking about running an a/b box with a to Normal 1, "b" to Bright 1, then using a patch cord to bridge Normal 2 and Bright 2. Other folks suggest bridging the two inputs with a patch cord.

 

Possible damage doing this? Does it really add anything (obviously I have not tried this yet for fear of "releasing the smoke" from my amp, which we all know is how amps work, 'cause if you let that smoke out, everything stops working).

 

Thanks

[myles_rose]

Originally posted by daddyelmis:

Myles:

 

Can bridging inputs hurt an amp? I've got a 59 Bassman RI and some guy was talking about running an a/b box with a to Normal 1, "b" to Bright 1, then using a patch cord to bridge Normal 2 and Bright 2. Other folks suggest bridging the two inputs with a patch cord.

 

Possible damage doing this? Does it really add anything (obviously I have not tried this yet for fear of "releasing the smoke" from my amp, which we all know is how amps work, 'cause if you let that smoke out, everything stops working).

 

Thanks

On the Tweed Bassman, you can bridge the inputs, just as on a Marshall Plexi (that has the same front end, as it was copied from this Bassman).

 

You do not want to do this on a Tolex era Bassman though.

[lg64strat]

Hi Myles,

I noticed that you commented on the Blue Angel in a HC forum, and appear to own one. Can you tell me anything about the Mesa Maverick? How it sounds on both channels? How is stacks up to other boogies, etc, etc.?

 

Thanks in advance...

lg64strat...

[PBBPaul]

Originally posted by myles111:

Originally posted by daddyelmis:

Myles:

 

Can bridging inputs hurt an amp? I've got a 59 Bassman RI and some guy was talking about running an a/b box with a to Normal 1, "b" to Bright 1, then using a patch cord to bridge Normal 2 and Bright 2. Other folks suggest bridging the two inputs with a patch cord.

 

Possible damage doing this? Does it really add anything (obviously I have not tried this yet for fear of "releasing the smoke" from my amp, which we all know is how amps work, 'cause if you let that smoke out, everything stops working).

 

Thanks

On the Tweed Bassman, you can bridge the inputs, just as on a Marshall Plexi (that has the same front end, as it was copied from this Bassman).

 

You do not want to do this on a Tolex era Bassman though.

Myles,

 

I've been bridging the inputs of my mid-70's Bassman for most of the past ten years by running a short cable between input 2 on the Normal channel and input 1 on the Studio channel. I've never had a problem. What's the scoop?

[exactopposite]

hey myles is the mesa maverick cathode biased. i'm looking at buying one (4x10) and i' curious to know for sure. if so, and i think it is, what range of tubes on the gt scale can the cathode bias properlly adjust itself for?

[Caevan O’Shite]

Originally posted by PBBPaul:

"I've been bridging the inputs of my mid-70's Bassman for most of the past ten years by running a short cable between input 2 on the Normal channel and input 1 on the Studio channel. I've never had a problem. What's the scoop?"

I'll take a tentative whack at this- Myles gave me permission to hop in here now and then, or I would feel like I was stepping on somebody's toes-

 

I seem to recall that the reason against this wasn't for fear of damage, but concerned a loading or phase issue, that would affect your tone.

 

If you like the way it sounds, then I think it's safe to stick with the jumpering.

 

If I can find further details- I've got all manner of books and magazines ferreted away in my packrat like digs- I'll return to post'em.

 

In the meantime, don't lose any sleep about it!

[myles_rose]

Originally posted by lg64strat:

Hi Myles,

I noticed that you commented on the Blue Angel in a HC forum, and appear to own one. Can you tell me anything about the Mesa Maverick? How it sounds on both channels? How is stacks up to other boogies, etc, etc.?

 

Thanks in advance...

lg64strat...

lg64strat....

 

This amp is a cathode biased amp with quad of EL84s and about 30-35 watts. They have a Mesa front end, not really a voxy sound, and not the cleans of the Bad Cats or Matchless 4xEL84 amps, a different sound.

 

They are not too fussy on tubes in the front end, they use a half a dozen of them in a very complex front end, so don't expect to hear big changes if you change the front end tubes to something fancy like NOS stuff. ... the front end is too complex to get the most of NOS tubes as compared to some other amps. The big plus here, is that just about any 12AX7 will work fine and dandy.

 

For output tubes, any mid range EL84 is fine, the GT scale of 4-6 is the same as the Mesa scale and this is on my website somewhere.

 

The effects loop does not work all that well with some of the newer devices such as a G Major. They take a lot of tweeking and balancing.

 

The front end is a not as pedal friendly as some of the other EL84 amps out there, but is about average and will work well enough for most folks.

 

If you are going to take the amp on the road, see if the version you are considering has nuts and bolts for the transformers. Some Mesa combo amps use self tapping sheet metal screws alone, and this has been a support problem for me with my Mesa clients on the road.

 

These are nice amps, but do have their limitations, but in their price range are pretty cool for the most part. Don't expect the touch sensitivity or definition of a more direct circuit amp. They will also not cover all that closely an AC-30 sound, which some folks think they should do, due to the output tube compliment.

 

Thes amps have a neg feedback loop, which most high end class A amps do not employ. This also makes them sound smaller for their wattage than something like an AC-30. In fact, a Dr Z MAZ JR rated at 18 watts, will be much stronger and cut through a mix more effectively, maybe even at less cost.

 

I hope this helped.

[myles_rose]

Originally posted by PBBPaul:

Originally posted by myles111:

Originally posted by daddyelmis:

Myles:

 

Can bridging inputs hurt an amp? I've got a 59 Bassman RI and some guy was talking about running an a/b box with a to Normal 1, "b" to Bright 1, then using a patch cord to bridge Normal 2 and Bright 2. Other folks suggest bridging the two inputs with a patch cord.

 

Possible damage doing this? Does it really add anything (obviously I have not tried this yet for fear of "releasing the smoke" from my amp, which we all know is how amps work, 'cause if you let that smoke out, everything stops working).

 

Thanks

On the Tweed Bassman, you can bridge the inputs, just as on a Marshall Plexi (that has the same front end, as it was copied from this Bassman).

 

You do not want to do this on a Tolex era Bassman though.

Myles,

 

I've been bridging the inputs of my mid-70's Bassman for most of the past ten years by running a short cable between input 2 on the Normal channel and input 1 on the Studio channel. I've never had a problem. What's the scoop?

You are fine .... on some of the latest black face reissues, they use shorting jacks that are connected differently to the internals, and you can set up a nasty feedback loop.

[lg64strat]

Re: Maverick

 

Myles,

Thanks for the Maverick info. Thats' exactly the thing I was looking for.

 

Best regards,

lg64strat...

[Richard Couch]

Hey Myles, glad to see your so busy here. And with none of that HCAF troll talk.

 

--richard

[myles_rose]

Originally posted by lg64strat:

Re: Maverick

 

Myles,

Thanks for the Maverick info. Thats' exactly the thing I was looking for.

 

Best regards,

lg64strat...

lg64strat ..........

 

You are more than welcome.

[roy d]

Myles,

I finally broke down and took my own advice and ordered a '73 silverface champ. It should arrive the middle of next week.

It already has a three prong power cable. The speaker is not original but is an old alnico something (we'll see what it sounds like). Tubes have been replaced with ones that are generic newer tubes - sovteks I think. I don't know if the caps were replaced...

Do I remember that the speaker is 3.2 ohms on this amp? Can you fit a 10 in there or are you stuck with the 8?

What else should I be thinking about to make this the best sounding little amp it could be?

thanks for the input

[meek20]

Bump!

[myles_rose]

Originally posted by roy d:

Myles,

I finally broke down and took my own advice and ordered a '73 silverface champ. It should arrive the middle of next week.

It already has a three prong power cable. The speaker is not original but is an old alnico something (we'll see what it sounds like). Tubes have been replaced with ones that are generic newer tubes - sovteks I think. I don't know if the caps were replaced...

Do I remember that the speaker is 3.2 ohms on this amp? Can you fit a 10 in there or are you stuck with the 8?

What else should I be thinking about to make this the best sounding little amp it could be?

thanks for the input

Roy,

 

It was generally a 4 ohm speaker, and with a new baffle board, a 10" may be fine.

 

I just wrote you back from one of my other emails that you sent some info to.

[jazzcaster]

Hello Myles, I hope all is well at Groove Tubes et al!

I'm hoping that you or some of the other knowledgable people here can elaborate on the difference between a 1x12 and a 2x10 speaker configuration in a combo amp? (sound wise, I mean). I'm looking at a Traynor YCV40, and it's offered in both configurations (all other aspects of the amps are equal). I notice that Peavey has a similar offering with their Delta Blues Series amps as well. I don't understand comments like "tighter bass end". What exactly does that mean? Volume between the two is not really an issue for me (both will be plenty loud for my needs).

 

I'm looking for some versatility in the amp to play jazz, blues, country and classic rock. No metal.

 

Any input would be much appreciated!

[michael c]

Hey Myles:

 

A lot of studios these days have a 1/4" wall jack in the control room to plug a speaker cable into from an amp head. This goes to the tracking room with another jack to plug your speaker cab into. These runs might be 75 to 100 feet with 2 connection jacks in between. How does this effect the tone on the amp/speaker? Does this load it down?

 

Thanks.

[myles_rose]

Originally posted by jazzcaster:

Hello Myles, I hope all is well at Groove Tubes et al!

I'm hoping that you or some of the other knowledgable people here can elaborate on the difference between a 1x12 and a 2x10 speaker configuration in a combo amp? (sound wise, I mean). I'm looking at a Traynor YCV40, and it's offered in both configurations (all other aspects of the amps are equal). I notice that Peavey has a similar offering with their Delta Blues Series amps as well. I don't understand comments like "tighter bass end". What exactly does that mean? Volume between the two is not really an issue for me (both will be plenty loud for my needs).

 

I'm looking for some versatility in the amp to play jazz, blues, country and classic rock. No metal.

 

Any input would be much appreciated!

jazzcaster...........

 

This is hard to answer, or should I say, complex.

 

It gets in mids, and dispersion, and all sorts of things.

 

The best thing you can do is listen to a 2x10 and 1x12 through the same amp.

[myles_rose]

Originally posted by michael c:

Hey Myles:

 

A lot of studios these days have a 1/4" wall jack in the control room to plug a speaker cable into from an amp head. This goes to the tracking room with another jack to plug your speaker cab into. These runs might be 75 to 100 feet with 2 connection jacks in between. How does this effect the tone on the amp/speaker? Does this load it down?

 

Thanks.

michael ..........

 

Not much problem as long as the wire is 14 gauge or larger.

 

There will be more HF loss in the studio effects racks, etc.

[henryrobinett]

Myles, How you doing? I've never used your advice column before.

 

Here's a real stupid specific question that I'm sure will be impossible to diagnose, but maybe you can tell me where I should look. All my gear is pretty old but stable and gives me what I require so why change?

 

I have a channel that keeps cutting out at unexpected times. I run stereo.

I have a Boogie Quad preamp. The effect send goes to a patch bay which sends virgin input signals to various rack mounted effects. They go into a Roland Line Mixer and the stereo outputs from that goes back into the stereo effect loop return on the Boogie. The Boogie outputs in turn go to a small Randall RRM 2-80 power amp.

 

I'll play and if I lose a channel al I have to do is go back and jiggle either the loop return, channel A of the main outs from the Boogie or EVEN TURNING OFF THE REVERB RACK MOUNT EFFECT. I have no idea why these various things effect the channel going off/on. If I disconnect the effects loop all is OK, leading me to believe that it's not the amp particularly, but either in the effects loop, the line mixer output or perhaps the gain staging is set too low?

 

The sound is sometimes a breaking up sound. Maybe a tube going bad? Sometimes the volume cuts down and then jumps out, as if a jack is being disconnected. Do you think these are all separate problems or is there something you think I should look at specifically?

 

I hope this makes some sense. I'd hate to just dump all my rack gear at a repair shop without at least a good diagnosis. Help.

[myles_rose]

Originally posted by henryrobinett:

Myles, How you doing? I've never used your advice column before.

 

Here's a real stupid specific question that I'm sure will be impossible to diagnose, but maybe you can tell me where I should look. All my gear is pretty old but stable and gives me what I require so why change?

 

I have a channel that keeps cutting out at unexpected times. I run stereo.

I have a Boogie Quad preamp. The effect send goes to a patch bay which sends virgin input signals to various rack mounted effects. They go into a Roland Line Mixer and the stereo outputs from that goes back into the stereo effect loop return on the Boogie. The Boogie outputs in turn go to a small Randall RRM 2-80 power amp.

 

I'll play and if I lose a channel al I have to do is go back and jiggle either the loop return, channel A of the main outs from the Boogie or EVEN TURNING OFF THE REVERB RACK MOUNT EFFECT. I have no idea why these various things effect the channel going off/on. If I disconnect the effects loop all is OK, leading me to believe that it's not the amp particularly, but either in the effects loop, the line mixer output or perhaps the gain staging is set too low?

 

The sound is sometimes a breaking up sound. Maybe a tube going bad? Sometimes the volume cuts down and then jumps out, as if a jack is being disconnected. Do you think these are all separate problems or is there something you think I should look at specifically?

 

I hope this makes some sense. I'd hate to just dump all my rack gear at a repair shop without at least a good diagnosis. Help.

Henry ........

 

If you gear is old, that sort of has little if anything to do with the sound ... all the new folks for the most part are trying to cop the tone of the old stuff

 

On channels cutting out in your Mesa Quad, there is not a lot in these that have to do with these that is not too easily traced.

 

It sounds like your jacks need to be cleaned and possibly retensioned.

 

I think the best bet is to pull all the tubes and clean the sockets, clean the jacks and pots, and generally just do a service on the unit as far as a generally cleaning and checking.

 

This is pretty fast and easy to do yourself with a good can of tuner cleaner/lube (do not use just cleaner ... and do not use WD-40).

 

That is where I would start.

[michael c]

Originally posted by myles111:

Originally posted by michael c:

Hey Myles:

 

A lot of studios these days have a 1/4" wall jack in the control room to plug a speaker cable into from an amp head. This goes to the tracking room with another jack to plug your speaker cab into. These runs might be 75 to 100 feet with 2 connection jacks in between. How does this effect the tone on the amp/speaker? Does this load it down?

 

Thanks.

michael ..........

 

Not much problem as long as the wire is 14 gauge or larger.

 

There will be more HF loss in the studio effects racks, etc.

Thank you.

 

Still trying to decide between the Ghia, KT45 and Route 66 for that studio amp!

[myles_rose]

Originally posted by michael c:

Originally posted by myles111:

Originally posted by michael c:

Hey Myles:

 

A lot of studios these days have a 1/4" wall jack in the control room to plug a speaker cable into from an amp head. This goes to the tracking room with another jack to plug your speaker cab into. These runs might be 75 to 100 feet with 2 connection jacks in between. How does this effect the tone on the amp/speaker? Does this load it down?

 

Thanks.

michael ..........

 

Not much problem as long as the wire is 14 gauge or larger.

 

There will be more HF loss in the studio effects racks, etc.

Thank you.

 

Still trying to decide between the Ghia, KT45 and Route 66 for that studio amp!

Michael,

 

The KT-45 is an amp that I would not use too often in a studio .... way too much level for large diaphram mics.

 

The Route 66 is cool in the studio or on the stage.

 

The Carmen Ghia is almost a requirement in any studio asenal. It can do most anything. The fact it is a lot cheaper than the other two amps is also sort of cool.