Feel free to ask Myles

[Marzuki Grinage]

Myles,

 

So that's what was causing the rattling that I heard when playing that amp!

 

Thanks for the reply, that's some useful info to know.

 

Marzuki.

[Wickerman]

Hey Mr Rose...

I recently bought a Marshall JCM2000 DSL401. I love it, it's a wonderful amp and all but I'm getting a horrible squelch feedback when at high volumes. I'm running a noise gate and even when my guitar's volume is off, the amp squeels on the dirty channel at high volumes. Now, I thought it might be a microphonic tube but I turned her on, let her warm up for a few minutes and tapped lightly on the tubes with a screwdriver handle and non of them made more than a slight ringing noise... If you have any ideas... PLEASE HELP!

[myles_rose]

Originally posted by Wickerman:

Hey Mr Rose...

I recently bought a Marshall JCM2000 DSL401. I love it, it's a wonderful amp and all but I'm getting a horrible squelch feedback when at high volumes. I'm running a noise gate and even when my guitar's volume is off, the amp squeels on the dirty channel at high volumes. Now, I thought it might be a microphonic tube but I turned her on, let her warm up for a few minutes and tapped lightly on the tubes with a screwdriver handle and non of them made more than a slight ringing noise... If you have any ideas... PLEASE HELP!

Wickerman..........

 

Swap out V1 for the fun of it ...... you may have a tube that ocillates, not necessarily microphonic.

[ci88]

hey Myles,

im looking for a head. i want the famous marshall jcm800 distortion as well as good cleans. i was thinking of getting a jcm800 2203, but i want at least two channels. i've been looking at the marshall dsl 100, tsl 100, and the randall vmax. which ones have tones most like the jcm800 2203, yet better cleans? i also heard that the dsl 50 was better than the dsl 100.can you please help me out and compare these four?

[myles_rose]

Originally posted by ci88:

hey Myles,

im looking for a head. i want the famous marshall jcm800 distortion as well as good cleans. i was thinking of getting a jcm800 2203, but i want at least two channels. i've been looking at the marshall dsl 100, tsl 100, and the randall vmax. which ones have tones most like the jcm800 2203, yet better cleans? i also heard that the dsl 50 was better than the dsl 100.can you please help me out and compare these four?

These are all nice amps. The most clean will come from the 100 watters, but the 50 watters have more than enough clean headroom for most any user I have dealt with, and are generally the preferred wattage of any of the Marshall models for a more versitile amp.

 

None of the DSL or TSL amps sounds quite like the JCM 800.

 

The Randall is even more different than the other three amps but may have other aspects you find great.

 

This is a tough call, and it would be best for you to play all the amps and try to compare. Remember, if an amp cannot do a good clean sound, all it's other sounds will be compromised.

[ci88]

Originally posted by myles111:

Originally posted by ci88:

hey Myles,

im looking for a head. i want the famous marshall jcm800 distortion as well as good cleans. i was thinking of getting a jcm800 2203, but i want at least two channels. i've been looking at the marshall dsl 100, tsl 100, and the randall vmax. which ones have tones most like the jcm800 2203, yet better cleans? i also heard that the dsl 50 was better than the dsl 100.can you please help me out and compare these four?

These are all nice amps. The most clean will come from the 100 watters, but the 50 watters have more than enough clean headroom for most any user I have dealt with, and are generally the preferred wattage of any of the Marshall models for a more versitile amp.

 

None of the DSL or TSL amps sounds quite like the JCM 800.

 

The Randall is even more different than the other three amps but may have other aspects you find great.

 

This is a tough call, and it would be best for you to play all the amps and try to compare. Remember, if an amp cannot do a good clean sound, all it's other sounds will be compromised.

would there be one that you would recommend more fot like metal and hard rock?

[myles_rose]

Originally posted by ci88:

Originally posted by myles111:

Originally posted by ci88:

hey Myles,

im looking for a head. i want the famous marshall jcm800 distortion as well as good cleans. i was thinking of getting a jcm800 2203, but i want at least two channels. i've been looking at the marshall dsl 100, tsl 100, and the randall vmax. which ones have tones most like the jcm800 2203, yet better cleans? i also heard that the dsl 50 was better than the dsl 100.can you please help me out and compare these four?

These are all nice amps. The most clean will come from the 100 watters, but the 50 watters have more than enough clean headroom for most any user I have dealt with, and are generally the preferred wattage of any of the Marshall models for a more versitile amp.

 

None of the DSL or TSL amps sounds quite like the JCM 800.

 

The Randall is even more different than the other three amps but may have other aspects you find great.

 

This is a tough call, and it would be best for you to play all the amps and try to compare. Remember, if an amp cannot do a good clean sound, all it's other sounds will be compromised.

would there be one that you would recommend more fot like metal and hard rock?

I would pass personally on all of them and go with either a Purplexing 100 or a Victoria Sovereign and forget the channel switching and go with a pedal board in front of a great sounding amp with no compromises.

[ci88]

hey myles,

do you think that i can get a good old 'tallica sound out of a marshall jcm2000 dsl50 with a bc rich nj warlock( loaded with a seymour duncan DDb and 59n) and a boss sd-1 pedal?

[Mike Gug]

Hey Myles, we've discussed me buying a Fender Cyber Deluxe. I've sinced been considering auditioning single pedals and keeping my solid state amp (Fender Deluxe 90).

 

I understand that any pedal will react and sound differently on a tube amp vs. a SS, but are there certain TYPES of pedals to avoid with SS vs. tubes? My first audition will be a Boss DS-1. Then I'll be looking into a chorus pedal.

 

One more question: what does the Ibanez Tube Screamer do? Please tell me it gives the warmth of a tube to a SS!

[Blue Note]

Myles,

 

Just wanted to thank you for answering my question back on page 44 about the dependability of a silver face Champ. Sorry it took so long for me to get back to you.

 

Later,

 

Blue Note

[daddyelmis]

Originally posted by myles111:

[/qb]

Look on my website, as there are amp techs there which I recommend.

 

Okay, dumb question, but what would be key questions and answers to ask a would-be amp tech before letting him/her do surgery on your amp? I've got a Bassman RI that I want to have a bias pot installed in, and there are no "full time" amp techs in my town (at least none obvious). Asking local musicians leads to "I know this guy . . . "

 

So, how would one determine whether the tech knows their stuff?? (BTW, I checked your amp tech section on the off hand there would be a list for NC, but no luck).

[myles_rose]

Originally posted by daddyelmis:

Originally posted by myles111:

Look on my website, as there are amp techs there which I recommend.

Okay, dumb question, but what would be key questions and answers to ask a would-be amp tech before letting him/her do surgery on your amp? I've got a Bassman RI that I want to have a bias pot installed in, and there are no "full time" amp techs in my town (at least none obvious). Asking local musicians leads to "I know this guy . . . "

 

So, how would one determine whether the tech knows their stuff?? (BTW, I checked your amp tech section on the off hand there would be a list for NC, but no luck).[/QB]

 

Don't worry about questions - go with their reputarion and get referrals or recommendations.

[ManInTheBox]

Myles, If I had a 50Watt amp, with an eight ohm output, what is the limit to the number or cabinets I dould hook up to it?

If I could manage to wire 10 cabs to gether with eight ohms of resistance, would this work??

would it be louder or quieter or the same as one 4x12?

[myles_rose]

Originally posted by tundrkys:

Myles, If I had a 50Watt amp, with an eight ohm output, what is the limit to the number or cabinets I dould hook up to it?

If I could manage to wire 10 cabs to gether with eight ohms of resistance, would this work??

would it be louder or quieter or the same as one 4x12?

As long as they were wired in some sort of series / parallel arrangement, you could have dozens of cabinets if the amp kept looking at 8 ohms.

[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

[steve f]

Myles,

 

What's the scoop on the reproduction Mullard preamp tubes GT is developing?

[myles_rose]

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.

[myles_rose]

Originally posted by steve f:

Myles,

 

What's the scoop on the reproduction Mullard preamp tubes GT is developing?

Steve,

 

All I can say at the moment, is that this is in progress and going well. The GE 6CA7 will probably be first, but we are doing both of these tubes in parallel.

[johnny5]

myles or any body who knows.

 

looking at the pre-amp tubes from back of a DSL50 head, which are which? i know the one farthest to the left (sheilded one) is V1.

 

really, i want to know which is the phase inverter and if the reverb is tube driven or not.

 

thanks,

john

[myles_rose]

Originally posted by johnny5:

myles or any body who knows.

 

looking at the pre-amp tubes from back of a DSL50 head, which are which? i know the one farthest to the left (sheilded one) is V1.

 

really, i want to know which is the phase inverter and if the reverb is tube driven or not.

 

thanks,

john

John,

 

V1 is your input and first gain stage, the tube closest to the input jack. V2 is also part of the tone. The phase inverter is closest to the output tubes. There are schematics on my website.

[Blue Note]

Myles,

 

I have won a bid on ebay for a digitech 2120 processor. My guess is you don't care for these and I am not a big fan of these complicated programmable devices either but hey they quit making them and I guess the collector side of me said that since it is obsolete I gotta have one.

 

Any way it has two 12AX7 tubes in it and before I even attempt to start tweaking on the sounds I would like to replace the tubes. Do you have a recomendation?

 

Thank You,

 

Blue Note

[myles_rose]

Originally posted by Blue Note:

Myles,

 

I have won a bid on ebay for a digitech 2120 processor. My guess is you don't care for these and I am not a big fan of these complicated programmable devices either but hey they quit making them and I guess the collector side of me said that since it is obsolete I gotta have one.

 

Any way it has two 12AX7 tubes in it and before I even attempt to start tweaking on the sounds I would like to replace the tubes. Do you have a recomendation?

 

Thank You,

 

Blue Note

Blue Note .........

 

These are actually pretty cool. There is a lot of signal processing, so differences in preamp tubes are not too noticible. I normally use 12AX7C tubes in these and the ADA.

[James-Italy]

Bump for Otto.

[otto]

Hi Miles (and everybody out there), I have a JCM 800 split channel 50 W (4210), bought few weeks ago. Fantastic sound! Tubed with Groove Tubes EL34 (type 4), 2 or 3 years old. After reading the biasing cathode resistore method, I decided to make a trial to understand if the fantastic sound I hear is obtained at 50% or 70% of maximum power, to have a comparison for a next retubing.

I weld on the cathode the 1-ohm resistors (very accurate value, 5 watt). Turn the amplifier on, warming up, then I measure the voltage on the anode: 450 V. OK, on the cathode resistor I should measure something between 38 and 48 (also considering the 10 mA grid current). I read 34 on one tube and 28 on the other!!

How is it possible that I love that sound so much if the tubes are completely not coupled and the Bias is so low?!

Reply: there is something wrong with my ears! But few weeks ago I played with a fantastic VHT, which is a very good comparison… so I don't understand.

Now I've biased the two tubes at 46 and 38 to have one tube near 65% and the other one near 50%. I think it should be the case to retube the amp, but I'd like to understand…

- The tubes are unbalanced because they are old?

- What a very low biasing (about 30%) involves? Only bad sound or also short life?

- My 4210 is a '82 model and clipping is obtained through diodes after the preamp valves. The EL34s were completely unmatched and worked with very low current so I think they were able to colour very little the sound. I compared the JCM 800 with a Valvestate and with a VHT Pittbull and there is no doubt: the sound is that of a great tube amp. The question is: how is it possible to hear a typical tube sound if preamp tubes are not used for distorsion and EL34s were used so cold?

Thank you

[Blue Note]

Myles,

 

Thanks for the advice on the 2120, I placed my order for some 12AX7C's from Groove Tubes and I am anxious to try them out.

 

Thanks again.

 

Blue Note

[myles_rose]

Originally posted by otto:

Hi Miles (and everybody out there), I have a JCM 800 split channel 50 W (4210), bought few weeks ago. Fantastic sound! Tubed with Groove Tubes EL34 (type 4), 2 or 3 years old. After reading the biasing cathode resistore method, I decided to make a trial to understand if the fantastic sound I hear is obtained at 50% or 70% of maximum power, to have a comparison for a next retubing.

I weld on the cathode the 1-ohm resistors (very accurate value, 5 watt). Turn the amplifier on, warming up, then I measure the voltage on the anode: 450 V. OK, on the cathode resistor I should measure something between 38 and 48 (also considering the 10 mA grid current). I read 34 on one tube and 28 on the other!!

How is it possible that I love that sound so much if the tubes are completely not coupled and the Bias is so low?!

Reply: there is something wrong with my ears! But few weeks ago I played with a fantastic VHT, which is a very good comparison… so I don't understand.

Now I've biased the two tubes at 46 and 38 to have one tube near 65% and the other one near 50%. I think it should be the case to retube the amp, but I'd like to understand…

- The tubes are unbalanced because they are old?

- What a very low biasing (about 30%) involves? Only bad sound or also short life?

- My 4210 is a '82 model and clipping is obtained through diodes after the preamp valves. The EL34s were completely unmatched and worked with very low current so I think they were able to colour very little the sound. I compared the JCM 800 with a Valvestate and with a VHT Pittbull and there is no doubt: the sound is that of a great tube amp. The question is: how is it possible to hear a typical tube sound if preamp tubes are not used for distorsion and EL34s were used so cold?

Thank you

Otto.....

 

GT has at least four different EL-34 tubes, so it is hard to know what you have in the amp. There should be more than just EL-34 on the tubes ... maybe EL34B or EL34R or EL34R2 or E34LS

 

The "4" means a softer rating. This is all covered in my Tube Primer downloads off my website.

 

Your tubes sound worn. Statically matched (non-GT) tubes may be close when new at idle match. Dynamically matched tubes may be farther off at idle but will match across the operating range. This also is all on my website.

 

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.

 

Most of your other questions are covered on my website.

[myles_rose]

Originally posted by Blue Note:

Myles,

 

Thanks for the advice on the 2120, I placed my order for some 12AX7C's from Groove Tubes and I am anxious to try them out.

 

Thanks again.

 

Blue Note

You are more than welcome.

[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?

[myles_rose]

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?

Otto,

 

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.

[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%?