Feel free to ask Myles

[untalented]

Myles -

 

Thanks a lot for your response, what do you think of the Air Brake vs. THD's Hot Plate?

 

I'm partial to the Air Brake just cos I can use it with anything else I pick up, but it seems to be impossible to find one.

[myles_rose]

Originally posted by untalented:

Myles -

 

Thanks a lot for your response, what do you think of the Air Brake vs. THD's Hot Plate?

 

I'm partial to the Air Brake just cos I can use it with anything else I pick up, but it seems to be impossible to find one.

I think each of the units is great and they each have their cool aspects. One cool THD aspect is the line out feature which we use on Carl Verheyen's live rig to feed his effects rack. One cool aspect of the Airbrake is nothing to set for impedance, simplicity, and small size. I use both of them extensively.

[headlow]

Hey Miles, I've got a slight problem I'm wondering if you can help me with?

 

I use a Laney VC30 112, usually ran at about half volume on the clean channel with a Hotplate. Today whilst playing I noticed a high pitched squealing coming from the amp. It happened with both my guitars, and with and without my pedal board hooked up (so I'm sure its not something caused by my pedals)

I'm thinking it could be a tube problem, but the amp was completely re-tubed only a month ago. Plus on average the amp only gets used about an hour a day.

 

Thanks in advance for any help you can give me.

[myles_rose]

Originally posted by headlow:

Hey Miles, I've got a slight problem I'm wondering if you can help me with?

 

I use a Laney VC30 112, usually ran at about half volume on the clean channel with a Hotplate. Today whilst playing I noticed a high pitched squealing coming from the amp. It happened with both my guitars, and with and without my pedal board hooked up (so I'm sure its not something caused by my pedals)

I'm thinking it could be a tube problem, but the amp was completely re-tubed only a month ago. Plus on average the amp only gets used about an hour a day.

 

Thanks in advance for any help you can give me.

You have a microphonic tube, even though it is new. This is very common in todays tubes. It should be covered under warranty for at least 90 days (six months if it is a GT tube).

[scatterbrain]

Hi myles,ive been listening to some of Jack Johnsons songs and was wondering would you know what guitar he uses on the song "stapple it together" and "holes to heaven".Theres a sort of ska sound to the guitar and i would maybe like to invest in one.

Thanks,Chris

[myles_rose]

Originally posted by scatterbrain:

Hi myles,ive been listening to some of Jack Johnsons songs and was wondering would you know what guitar he uses on the song "stapple it together" and "holes to heaven".Theres a sort of ska sound to the guitar and i would maybe like to invest in one.

Thanks,Chris

I have no idea.

[scatterbrain]

No problem,Ill ask in the forum.maybe someone there will know.Thanks anyway.

[picker]

Myles,

I am having a problem with my Reverend Goblin amp. It's started distorting at any volume level. I have checked the tubes and they are all intact and firmly in their sockets. It has not been abused in any way, and it does it hooked up to any speaker, so it's not that. I don't know what the problem could be. Any ideas?

[myles_rose]

Originally posted by Picker:

Myles,

I am having a problem with my Reverend Goblin amp. It's started distorting at any volume level. I have checked the tubes and they are all intact and firmly in their sockets. It has not been abused in any way, and it does it hooked up to any speaker, so it's not that. I don't know what the problem could be. Any ideas?

This could be many things. If you know the tubes are good via a proper tube tester then it looks like it is time for the amp to see a tech's bench. It could be too many things to guess here without having the amp on a bench.

[Rock Soldier]

Originally posted by myles111:

Originally posted by TheOtherLee:

Originally posted by myles111:

quote:

---

Originally posted by TheOtherLee:

Hi Myles, Ive been looking all over the internet but cant find a straight explaination on what the difference is between lin and log pots. Can you help out at all? I am asking because I have put together a Fuzz Face pedal and have used a Log pot for the Fuzz control, this is all i have that is the right value but I am only getting a sound when the guitar is played extremely loudly with the volume cranked right up... and then the sound swells and dies out very quickly. The instructions say to use a linear pot, could this be the cause of my problem?

 

Im not sure if you can help as I know your an amp expert by trade, but any help would be greatly appreciated.

 

Thanks

 

Lee

Lee ...

 

There are generally three types of pots ... linear, log, and audio.

 

Think of a linear pot that goes from 1-10 with the numbers being equally spaced so at 1 we are at 10% of the level or effect, 5=50% etc.

 

Audio and log taper pots have their own scales which are not linear ... say 3=20% and 7=40% as an example with most of the change in the 8-10 range. The log pot follows it's own paticular taper.

 

This is precisely your problem.

Thanks for your help myles... And why couldnt all these sites that state "how pots work" jsut say what you did... You have a good way of explaining

I have the right pot on order so hopefully all will be sorted

Lee ... it is not a matter of your problem "hopefully" being resolved with the proper pot, it will totally be resolved

---

In a related question. When selecting pots for an electric guitar, am I correct in saying you should use an audio taper for a volume pot and a linear taper for a tone pot? Or do I have this backwards? I did read some where you could use audio taper for both.

[picker]

Originally posted by myles111:

Originally posted by Picker:

Myles,

I am having a problem with my Reverend Goblin amp. It's started distorting at any volume level. I have checked the tubes and they are all intact and firmly in their sockets. It has not been abused in any way, and it does it hooked up to any speaker, so it's not that. I don't know what the problem could be. Any ideas?

This could be many things. If you know the tubes are good via a proper tube tester then it looks like it is time for the amp to see a tech's bench. It could be too many things to guess here without having the amp on a bench.

I took the amp back to the store, and their tech guy says he thinks the Groove Tubes I put in to replace the Electro Harmonix tubes it came with are the wrong bias, and that the amp needs to be biased. Now, when I replaced the tubes, there was no problem. The distortion developed a while after I changed them out, not immediately, which I would have thought would be the case if the bias was wrong. And, I was under the impression that a matched set of replacement tubes wouldn't require re-biasing. I asked what biasing the amp for the tubes would cost, and they told me $30, if the tubes didn't need replacing, more if they did, of course.

Am I being hosed or not?

[myles_rose]

Originally posted by Picker:

Originally posted by myles111:

Originally posted by Picker:

Myles,

I am having a problem with my Reverend Goblin amp. It's started distorting at any volume level. I have checked the tubes and they are all intact and firmly in their sockets. It has not been abused in any way, and it does it hooked up to any speaker, so it's not that. I don't know what the problem could be. Any ideas?

This could be many things. If you know the tubes are good via a proper tube tester then it looks like it is time for the amp to see a tech's bench. It could be too many things to guess here without having the amp on a bench.

I took the amp back to the store, and their tech guy says he thinks the Groove Tubes I put in to replace the Electro Harmonix tubes it came with are the wrong bias, and that the amp needs to be biased. Now, when I replaced the tubes, there was no problem. The distortion developed a while after I changed them out, not immediately, which I would have thought would be the case if the bias was wrong. And, I was under the impression that a matched set of replacement tubes wouldn't require re-biasing. I asked what biasing the amp for the tubes would cost, and they told me $30, if the tubes didn't need replacing, more if they did, of course.

Am I being hosed or not?

If they are the SAME type tubes at the SAME rating AND the amp was biased properly in the first place (and most factory amps are not from my experience) then it is plug and play.

[musicallyNumb]

Hi Myles,

Looks like you can be my only savior, as I am quite new to this wolrd of Amps. I want to start creating a new Amp from scratch! And I have no idea where to start learning the basics. Can you give me some pointers where I can have a smooth journey!

I want to know more about the Cabinets, modelling and the elecrtonics involved(preferrably a basic circuitry that I can tweak).

Can you help me? Would be really grateful.

[Joe Shaw]

I have a reissue Vox 15 (about 1995 made in England) that I believe has a bad power transformer. I replaced this transformer 6 years ago. The amp just died, no power, but no blown fuse either. This time it is blowing it's 500mA main fuse. I put a Fluke 87 in current mode and placed it in circuit. The amp works and sounds good. It draws 400mA on stand-by and 600 mA turned all the way up. However, it blows a 1.5 A fuse. I bought new output tubes and a new 5Y3 to no avail. It also blew a 1.5 A fuse with the 5Y3 out. I have the transformer here on the bench. I was hoping that you could give me an idea of how to test and make sure this bad before I buy another one. I have a Sencore Z meter and enter an erroneous value to get started. The primary told me it was 233 mH, but it says 5 rings and Bad. The secondaries ring bad as well. With an ohmmeter and the primary facing me, starting at the bottom right and going clockwise, I get 7ohms, 8 Ohms on the primary side and .3 Ohms, 112 Ohms, 234 Ohms, and .3 Ohms on the secondary. I did not disconnect the entire secondary and power the amp up. Please help.

[myles_rose]

Originally posted by musicallyNumb:

Hi Myles,

Looks like you can be my only savior, as I am quite new to this wolrd of Amps. I want to start creating a new Amp from scratch! And I have no idea where to start learning the basics. Can you give me some pointers where I can have a smooth journey!

I want to know more about the Cabinets, modelling and the elecrtonics involved(preferrably a basic circuitry that I can tweak).

Can you help me? Would be really grateful.

This is an easy one ....

 

Get this new book:

 

The Guitar Amp Handbook : Understanding Amplifiers and Getting Great Sounds

 

It is by Dave Hunter and one of the best books on amps that I have ever seen.

 

 

http://www.amazon.com/gp/product/087930863X/sr=8-3/qid=1152714916/ref=pd_bbs_3/104-8393734-9668740?ie=UTF8

[myles_rose]

Originally posted by Joe Shaw:

I have a reissue Vox 15 (about 1995 made in England) that I believe has a bad power transformer. I replaced this transformer 6 years ago. The amp just died, no power, but no blown fuse either. This time it is blowing it's 500mA main fuse. I put a Fluke 87 in current mode and placed it in circuit. The amp works and sounds good. It draws 400mA on stand-by and 600 mA turned all the way up. However, it blows a 1.5 A fuse. I bought new output tubes and a new 5Y3 to no avail. It also blew a 1.5 A fuse with the 5Y3 out. I have the transformer here on the bench. I was hoping that you could give me an idea of how to test and make sure this bad before I buy another one. I have a Sencore Z meter and enter an erroneous value to get started. The primary told me it was 233 mH, but it says 5 rings and Bad. The secondaries ring bad as well. With an ohmmeter and the primary facing me, starting at the bottom right and going clockwise, I get 7ohms, 8 Ohms on the primary side and .3 Ohms, 112 Ohms, 234 Ohms, and .3 Ohms on the secondary. I did not disconnect the entire secondary and power the amp up. Please help.

Joe,

 

I think you are getting too complicated too fast ....

 

Right off the bat ... the new rectifier, whose is it? Many of the current 5Y3 rectifiers are far off proper spec and your plate voltages may be extreme.

 

This could be many things and these amps were complex PCB amps and there could be many things that would cause this.

 

I'd need to see the amp first to measure all voltages.

[Joe Shaw]

Originally posted by myles111:

Since I only get email notification on the subjects I post, I have missed some that get pushed back as the days progress. I find some questions with my name in the subject on occasion, and would like to miss less of these.

 

So .... I am putting this post up here, so if you have a question or have a comment, just post a comment here and when I see the email notification I will answer back here as quickly as I am able. If I don't get to it in a day or two, please forgive me. I generally try to get to this in the early morning or later evening, but while we are testing and destroying tubes (which takes time while they "bake"),I try to get onto this.

 

Regards,

 

Myles

[Joe Shaw]

The 5Y3 is a Soltek. The one I replaced was a made in the USA Sylvania. I guess I had this on the shelf. Could the Power transformer be bad or out of tolerance and still work, like it does with a current meter in place of the fuse? Do you know where I could get the Schematic that has voltages listed on it?

[myles_rose]

Originally posted by Joe Shaw:

The 5Y3 is a Soltek. The one I replaced was a made in the USA Sylvania. I guess I had this on the shelf. Could the Power transformer be bad or out of tolerance and still work, like it does with a current meter in place of the fuse? Do you know where I could get the Schematic that has voltages listed on it?

The Sovtek has excessive voltages for a 5Y3 in their last few runs.

 

Contact Vox for the prints but also look on my website as the prints may be there too.

[Big Red 67]

Why exactly is tube production not environmentally friendly? Just a question that came up on the guitar forum at musicplayer. Thanks, Tate

[picker]

Originally posted by myles111:

Originally posted by Picker:

Originally posted by myles111:

quote:

---

Originally posted by Picker:

Myles,

I am having a problem with my Reverend Goblin amp. It's started distorting at any volume level. I have checked the tubes and they are all intact and firmly in their sockets. It has not been abused in any way, and it does it hooked up to any speaker, so it's not that. I don't know what the problem could be. Any ideas?

This could be many things. If you know the tubes are good via a proper tube tester then it looks like it is time for the amp to see a tech's bench. It could be too many things to guess here without having the amp on a bench.

I took the amp back to the store, and their tech guy says he thinks the Groove Tubes I put in to replace the Electro Harmonix tubes it came with are the wrong bias, and that the amp needs to be biased. Now, when I replaced the tubes, there was no problem. The distortion developed a while after I changed them out, not immediately, which I would have thought would be the case if the bias was wrong. And, I was under the impression that a matched set of replacement tubes wouldn't require re-biasing. I asked what biasing the amp for the tubes would cost, and they told me $30, if the tubes didn't need replacing, more if they did, of course.

Am I being hosed or not?

If they are the SAME type tubes at the SAME rating AND the amp was biased properly in the first place (and most factory amps are not from my experience) then it is plug and play.

---

Well the GTs were GT6V6Cs with a rating of 6, and the Electro Harmonix tubes I repleced with them say "6V6GT" then "electro harmonix", then "Made in Russia", then "04 08" and handwritten in Magic Marker on the top of the tube is a "46". Total mismatch?

[myles_rose]

Originally posted by Big Red 67:

Why exactly is tube production not environmentally friendly? Just a question that came up on the guitar forum at musicplayer. Thanks, Tate

There are some caustic materials used.

[myles_rose]

Originally posted by Picker:

Originally posted by myles111:

Originally posted by Picker:

quote:

---

Originally posted by myles111:

quote:

---

Originally posted by Picker:

Myles,

I am having a problem with my Reverend Goblin amp. It's started distorting at any volume level. I have checked the tubes and they are all intact and firmly in their sockets. It has not been abused in any way, and it does it hooked up to any speaker, so it's not that. I don't know what the problem could be. Any ideas?

This could be many things. If you know the tubes are good via a proper tube tester then it looks like it is time for the amp to see a tech's bench. It could be too many things to guess here without having the amp on a bench.

I took the amp back to the store, and their tech guy says he thinks the Groove Tubes I put in to replace the Electro Harmonix tubes it came with are the wrong bias, and that the amp needs to be biased. Now, when I replaced the tubes, there was no problem. The distortion developed a while after I changed them out, not immediately, which I would have thought would be the case if the bias was wrong. And, I was under the impression that a matched set of replacement tubes wouldn't require re-biasing. I asked what biasing the amp for the tubes would cost, and they told me $30, if the tubes didn't need replacing, more if they did, of course.

Am I being hosed or not?

If they are the SAME type tubes at the SAME rating AND the amp was biased properly in the first place (and most factory amps are not from my experience) then it is plug and play.

---

Well the GTs were GT6V6Cs with a rating of 6, and the Electro Harmonix tubes I repleced with them say "6V6GT" then "electro harmonix", then "Made in Russia", then "04 08" and handwritten in Magic Marker on the top of the tube is a "46". Total mismatch?

---

Yes ... mismatched in tube type by maker and a static rating on the EH with a god only knows number of 46. Could be anything. If the plate voltage at test and bias are not known the number can be anywhere from 1-100 and mean nothing.

[WaterMan]

Hi Myles,

 

Haven't talked to you in a while, partly because every time I do, it costs me some substatial dough .

 

On the upside, however, you may recall I've acquired a number of great amps, including: Gerhart Gilmour, Pearson's Champ, Dr. Maz 18 Jr, and a custom Kingsley. My favorite is the Kingsley, I think because I'm drawn to clean headroom and the sound of 6L6s. The Kinglsey is a beast, however, with essentially two amps in one cabinet, and 2 12" speakers - too heavy to drag around on a regular basis.

 

So here's my question: Given that the Maz Jr head is my second favorite amp (really sweet through a Tone Tubby cab with a 12" hemp cone speaker), it would be an even more ideal amp for me if I could capture the 6L6 sound by changing tubes. Would you recommend this, and if so, which ones and what about preamp tubes?

 

The other option is to get a Carr Rambler, but I haven't heard one yet, nor do I want to shell out $2300 at this point.

 

Thanks again for the recommendations.

[Junior 1]

Myles,

Can I use a 15 watt SS guitar amp for a short scale bass at bedroom practice levels?

[Teahead]

Hi Myles, been having some trouble with a nasty 'buzz' on only one or two notes through my AC30. Swapped power tubes to no avail, should I look to the rectifier or the preamp tubes next?

 

Thanks.

[myles_rose]

Originally posted by WaterMan:

Hi Myles,

 

Haven't talked to you in a while, partly because every time I do, it costs me some substatial dough .

 

On the upside, however, you may recall I've acquired a number of great amps, including: Gerhart Gilmour, Pearson's Champ, Dr. Maz 18 Jr, and a custom Kingsley. My favorite is the Kingsley, I think because I'm drawn to clean headroom and the sound of 6L6s. The Kinglsey is a beast, however, with essentially two amps in one cabinet, and 2 12" speakers - too heavy to drag around on a regular basis.

 

So here's my question: Given that the Maz Jr head is my second favorite amp (really sweet through a Tone Tubby cab with a 12" hemp cone speaker), it would be an even more ideal amp for me if I could capture the 6L6 sound by changing tubes. Would you recommend this, and if so, which ones and what about preamp tubes?

 

The other option is to get a Carr Rambler, but I haven't heard one yet, nor do I want to shell out $2300 at this point.

 

Thanks again for the recommendations.

You have a pretty great inventory.

 

The Carr is a great amp but the Rambler (one of my favorites of Steve's amps) does not have all that much clean headroom. The headroom is almost gone at about 9:00 on the volume and above that the amp does not get as much louder as you would guess, it is more that it's distortion character changes.

 

On the MAZ Jr ... a trick I did on a MAZ Sr for one of the most well known Z players on the planet was to use a 5751 in V1 and a 5751 in the phase inverter. Then I had him plug into the low level input. Turn the master all the way up (so it is no longer a master volume amp) and see if the cleans are better for you. You can also go to a #7 set of EL84S output tubes but if you already have 6's it won't make that much difference.

[myles_rose]

Originally posted by Junior 1:

Myles,

Can I use a 15 watt SS guitar amp for a short scale bass at bedroom practice levels?

Yes if you keep the level down as the speaker was not designed for those frequencies. If you can disconnect the internal speaker and use an external cab with a more beefy speaker then you'd be in better shape.

[myles_rose]

Originally posted by Teahead:

Hi Myles, been having some trouble with a nasty 'buzz' on only one or two notes through my AC30. Swapped power tubes to no avail, should I look to the rectifier or the preamp tubes next?

 

Thanks.

I am hoping this buzz is physical from the amp and not a speaker buzz?

 

If so ... play the offending note (or have somebody do this) and take a bit if a rag (as not to burn yourself) and see if touching the rectifier makes this to away. The same can be done with the preamp tubes. You can also push on some of the internals. Hupefully your wire harness is long enough to allow the chassis to stay connected while being exposed enough to allow you to do this. Also hopefully ... when the chassis is pulled to do this you will still have the problem! Sometimes just moving things around changes symptoms.

 

If you are near me I would be happy to look at the amp and we could put in on a signal generator which is much faster and easier. No charge on this by the way as you are on this forum.

[Teahead]

I only wish I was near you, Myles. Three thousand miles of Atlantic Ocean and the width of the American continent lies between us, or to put it another way, I'm in Ireland.

 

I did pull the chasis and try what you've suggested, neither seemed to solve the trouble. How might I inspect to rule out speaker buzz?

 

I was running the amp through a Hotplate and the buzz didn't seem to get louder when the gain was increased with attenuation applied. It did get louder when the physical volume increased though. Could this indicate speaker trouble?

 

Thanks for your help.