Feel free to ask Myles

[myles_rose]

Originally posted by Mike1959:

Myles, thanks will do. Though I'm not sure when that might be as I've sent the tubes back and I've decided to work with the #8s for a while. Get my moneys worth

 

Mike

Mike - keep in touch.

 

On your private message - let me know what happens and in the future, it is better to just email me rather than send PMs

[Mike1959]

Myles - will do. But in the meantime, if I could just trouble you again...

 

I replaced the V5 with a 12AX7M and was impressed with the results. My understanding is that the long plate version outputs a high amplitude -which I think would drive the output stage harder. Changing #8s to #6s would make the tubes distort earlier? Or was there something more?

 

By the way your web site has a ton of great info! I will, be browsing there from time to time. Hope to soak up a little bit of your wealth of knowledge.

 

Thanks again.

Mike

[myles_rose]

Originally posted by Mike1959:

Myles - will do. But in the meantime, if I could just trouble you again...

 

I replaced the V5 with a 12AX7M and was impressed with the results. My understanding is that the long plate version outputs a high amplitude -which I think would drive the output stage harder. Changing #8s to #6s would make the tubes distort earlier? Or was there something more?

 

By the way your web site has a ton of great info! I will, be browsing there from time to time. Hope to soak up a little bit of your wealth of knowledge.

 

Thanks again.

Mike

Mike,

 

One of the reasons you like the M in there is because a 12AX7 should put out 1.2mA of current drive and most preamp tubes today are at about 0.6-0.8mA, so you can be as much as 50% on current output which is different than gain or transconductance. The M's are some of the strongest out there today.

 

The 8's will distort later than the 6's and give you a bit more clean headroom than a 6.

[Mike1959]

Thanks Myles. I will let you know how things turn out.

 

Mike

[Rigz]

Hello Myles, I posted this question in the forums and was told you might have an answer. Do you know where I might find schematics for the Alamo Embassy 2553, Jet 2564, or Electra 2570. There doesn't seem to be much on the net. Thanks in advance,

 

Ben

[myles_rose]

Originally posted by Rigz:

Hello Myles, I posted this question in the forums and was told you might have an answer. Do you know where I might find schematics for the Alamo Embassy 2553, Jet 2564, or Electra 2570. There doesn't seem to be much on the net. Thanks in advance,

 

Ben

Ben,

 

Sorry, can't help you here as I have never worked on any of them.

 

Myles

[Rigz]

Ok, Thanks anyway Myles.

 

Ben

[AcerS]

Hi Myles, sorry to trouble you but since im quite new to amps, i need to get a comfirmation from someones lot better. I just bought a Marshall amp online, and the sound is great, but then, there was some noise even when i didnt touch my guitar(electric) strings. The noise is much louder when i put the volume to the max. When i plugged in my electro acoustic guitar, the noise is still there and whenever i get my guitar closer to the amps , the noise will become louder and vibrates inside my guitar. Is this normal for an amp, or my amp is broken.?

[myles_rose]

Originally posted by Rigz:

Ok, Thanks anyway Myles.

 

Ben

Ben,

 

Sorry I could not help here.

[myles_rose]

Originally posted by AcerS:

Hi Myles, sorry to trouble you but since im quite new to amps, i need to get a comfirmation from someones lot better. I just bought a Marshall amp online, and the sound is great, but then, there was some noise even when i didnt touch my guitar(electric) strings. The noise is much louder when i put the volume to the max. When i plugged in my electro acoustic guitar, the noise is still there and whenever i get my guitar closer to the amps , the noise will become louder and vibrates inside my guitar. Is this normal for an amp, or my amp is broken.?

Is the amp new or used?

 

Which Marshall?

 

Is is more of a 60 cycle hum or a hiss?

[Mike1959]

Hi Myles,

 

Re Nomad 45

 

I spent a lot of time with the amp this weekend. Although there has been a definite improvement in the tone, there is still an underlying, raucous tone. Almost like a dissonant sound you get with a maxed fuzz pedal. But here's the thing, sometimes I can hardly hear it and other times I find it so bad. Also, when I can hear it, the low end is really mushy.

 

Maybe this is just the way this map is meant to play, I don't know. I've owned Boogies before and the tone was always tight, even with the hi-gain settings.

 

I will be taking it to a Mesa tech during the week to have it checked. If he finds nothing wrong then maybe it's just me! Perhaps I should just stick with Marshalls.

 

Anyway, will let you know how it goes.

 

Thanks.

Mike

[myles_rose]

Originally posted by Mike1959:

Hi Myles,

 

Re Nomad 45

 

I spent a lot of time with the amp this weekend. Although there has been a definite improvement in the tone, there is still an underlying, raucous tone. Almost like a dissonant sound you get with a maxed fuzz pedal. But here's the thing, sometimes I can hardly hear it and other times I find it so bad. Also, when I can hear it, the low end is really mushy.

 

Maybe this is just the way this map is meant to play, I don't know. I've owned Boogies before and the tone was always tight, even with the hi-gain settings.

 

I will be taking it to a Mesa tech during the week to have it checked. If he finds nothing wrong then maybe it's just me! Perhaps I should just stick with Marshalls.

 

Anyway, will let you know how it goes.

 

Thanks.

Mike

Mike,

 

Let me know what you find.

 

Could it be an internal vibration? Pretty common in these amps.

[Mike1959]

Myles,

 

Thanks for the tip. I'll ask the tech to check for anything loose. I'm hoping to take it to the tech on Tuesday and pick it up later this week. I will post my findings.

 

Mike

[janalon]

Originally posted by CaevanO'Shite:

If I can butt in here...

 

Janalon- Joe-

 

It's looking to me as if you could quickly wind up putting a lot more than that original difference of $300.00 into this second amp, only to try to replicate the results of the first...

 

BEFORE YOU VOID YOUR WARRANTY by modifying that amp in any way... consider the following:

 

It might be much more cost-effective for you to purchase the first one (maybe trading-in the one you have, or selling it, to do so, unless you can still return it), and put any extra energy and money into keeping that one sounding and feeling the same via tubes and maintenance.

 

What do you think about this idea, Myles?

Hey Caevan,

 

Turns out the solution to my problems was much simpler than I expected.

 

As of last nite, I became so frustrated with the tone / sound quality that I went out to Home Depot to purchase an alan key to open the 3/4 back and take a look at the tubes.

 

Turns out that the alan screws doesn't open the back, but holds the tubes / inards of the amp in place. I screwed everything back in, and pushed up on the power tubes to make sure they weren't jostled loose. Whoala, all of my problems fixxed- the hiss went away and full bite / bass was restored.

 

The amp shipped with tubes attached. I am theorizing that one of the power tubes slipped down, causing a hiss and loss of tone. I guess I pushed the tube back into place during this incident.

 

I will still take it to a certified service technician to have it retubed and looked at thoroughly. Better safe than sorry, eh? BTW thanks for the tube guide Myles. Quite a thick read that should enrich my overall knowledge on the topic.

 

Joe

[myles_rose]

Joe - you are very welcome and happy playing

[Mike1959]

Hi Myles,

 

Re: Nomad 45

 

I was going to take my amp to the MESA tech when I realised that he is located other side of London. And as only accepts between 10 - 5pm, it would have cost to 2 days annual leave to deliver and collect. I contacted UK distributor and they have given me the name of a more local tech. Not only that, I am told he is THE tech in the UK when it comes to complex tube circuitry. I had a long conversation on the phone. He is also aware of the sympathetic vibration issues with this amp model, particularly with heat affected components rattling. He also suggested a bad speaker (didn't think of that one) and the possibility of burnt out carbon resistors.

 

Things are looking up again! I will deliver the amp to him this evening. Hopefully, I will have some good news by the end of the week.

 

Mike

[myles_rose]

Mike - good luck and I hope it all gets worked out nicely.

[Mike1959]

Thanks Myles.

[GtrWiz]

hey Miles,

 

Have you ever messed with a VHT Valvulator? I need to change the tube in mine, and was curious what tonal difference/possible harm, if any, would come from using something other than a 12ax7.

 

Chris

[myles_rose]

Originally posted by GtrWiz:

hey Miles,

 

Have you ever messed with a VHT Valvulator? I need to change the tube in mine, and was curious what tonal difference/possible harm, if any, would come from using something other than a 12ax7.

 

Chris

Chris,

 

You can try a 5751 and it may smooth things out a bit. No damage or harm.

[GtrWiz]

Originally posted by myles111:

Originally posted by GtrWiz:

hey Miles,

 

Have you ever messed with a VHT Valvulator? I need to change the tube in mine, and was curious what tonal difference/possible harm, if any, would come from using something other than a 12ax7.

 

Chris

Chris,

 

You can try a 5751 and it may smooth things out a bit. No damage or harm.

OK, I've found two a JAN-GE 5751 (JG-5751), and a sovtek 5751. What's the difference?

Chris

[myles_rose]

Originally posted by GtrWiz:

Originally posted by myles111:

Originally posted by GtrWiz:

hey Miles,

 

Have you ever messed with a VHT Valvulator? I need to change the tube in mine, and was curious what tonal difference/possible harm, if any, would come from using something other than a 12ax7.

 

Chris

Chris,

 

You can try a 5751 and it may smooth things out a bit. No damage or harm.

OK, I've found two a JAN-GE 5751 (JG-5751), and a sovtek 5751. What's the difference?

Chris

The JAN GE is a REAL one.

 

The Sovtek will trace nothing like a REAL one, it is more of an underpowered 12AX7 but .... maybe you will prefer it so try both.

 

The JAN GE will last for decades if it is a good one.

[Museeip]

Hi Myles, first of all thanks for all this stuff. Even before I joined the forum my good friend Bruce(flagshipmile) always had good things to say about you, so thanks for the help. Anyway, here's my question. I own a 96' Fender Twin Reverb reissue, and I do love it for that clean. I wish it had a little more bite and broke up a little, but I'm not opposed to using pedals for that. my real problem I have with it is the shear volume. For rehersals and gigs at clubs it's just too loud. I get the volume to about 4 and the soundguy and my bandmates are telling me to turn down. I feel like I'm not getting the tone I can because I can only run it on 3-4. Someday I will get a lower wattage amp, a Dr.Z is want I want(but that is a whole other post)but for now what is the best way to control the volume? I've heard 1)use an attenuator 2)use the THD yellow jackets 3) change the speakers, or 4)pull out 2 of the power tubes. Any words of advice would be greatly appreciated.

Thanks, John.

[myles_rose]

Originally posted by Museeip:

Hi Myles, first of all thanks for all this stuff. Even before I joined the forum my good friend Bruce(flagshipmile) always had good things to say about you, so thanks for the help. Anyway, here's my question. I own a 96' Fender Twin Reverb reissue, and I do love it for that clean. I wish it had a little more bite and broke up a little, but I'm not opposed to using pedals for that. my real problem I have with it is the shear volume. For rehersals and gigs at clubs it's just too loud. I get the volume to about 4 and the soundguy and my bandmates are telling me to turn down. I feel like I'm not getting the tone I can because I can only run it on 3-4. Someday I will get a lower wattage amp, a Dr.Z is want I want(but that is a whole other post)but for now what is the best way to control the volume? I've heard 1)use an attenuator 2)use the THD yellow jackets 3) change the speakers, or 4)pull out 2 of the power tubes. Any words of advice would be greatly appreciated.

Thanks, John.

John,

 

Bruce is a great song writer ... hope he is keeping it up.

 

The Twin Reverb Reissue is a great amp. I support a ton of them and they are used right in the middle of a mix of originals many times. I always said that if you cannot get a good clean sound out of an amp then it's not a great amp and the Twin Reverb has never suffered the lack of being able to get great clean tones.

 

These amps were never designed to distort but they do respond to a lot of pedals really nicely. At 4 these amps are LOUD.

 

There are a few things that you can think about that work great.

 

1 - you can turn the amp down to 2+ and use a Zendrive pedal.

 

http://www.guitaramplifierblueprinting.com/images/zendrive.jpg

 

This is one of the best sounding pedals I have ever seen or heard. It is also one that works over a really wide range ... from just a slight bit of overdrive to heavy distorted tones.

 

You can get these from www.hermidaaudio.com

 

Option 2 is a loadbox / attenuator. The one I love is the Dr. Z Air Brake ....

 

http://www.drzamps.com/images/zairbrake4.jpg

 

I used these in the bottom of the cabinets on Kenny Loggins' amps on their tour that just ended. I love these as they work with any impedance and have no AC plug and are really robust and simple.

 

More on these at http://www.drzamps.com/airbrake.html

 

If you want to go the class A conversion route such as the yellow jacket, GT also has a product that is similar. This device was actually invented by Red Rhodes decades ago.

 

You can use 2 of these or four of them. No bias or tools are necessary.

 

You will find those on the page here ... http://www.groovetubes.com/tubes_list.cfm?ObjectGroup_ID=110 and they are the 928PR.

 

http://www.groovetubes.com/groovetubes/images/gt_powereducer.jpg

 

South Valley Vintage Amps tested the Yellow Jacket and the GT 928PR and their results are here: http://www.groovetubes.com/assets/1778_GT928-PR_vs_THDYJSD_Test.pdf

 

You cannot pull out 1/2 the output tubes as there is no impedance selector in this amp.

 

Hope this helped...

 

Myles

[Museeip]

Thanks so much Myles. Bruce is good, in fact I graduate from school here in Denver in a few weeks and then I'll be moving back to Detroit to play in a band with Bruce again. I'll look into all these options, and when I'm ready and have some cash I'll ask you more about the different Dr.Z models.

 

Thanks again, John.

[myles_rose]

Originally posted by Museeip:

Thanks so much Myles. Bruce is good, in fact I graduate from school here in Denver in a few weeks and then I'll be moving back to Detroit to play in a band with Bruce again. I'll look into all these options, and when I'm ready and have some cash I'll ask you more about the different Dr.Z models.

 

Thanks again, John.

John,

 

You are quite welcome

[Steevo]

Hi Myles, just a quick question. I finally got my hands (ears) on a '65 Fender Champ ... looks all original ... sounds like shit. Maybe I'm expecting too much but from all I've read this little guy should sound pretty good. I'm playing my 2002 Gibson 356 through it, and it's just ... well, disappointing. I wanted it to be all tubey and swirly and have my notes 'bloom' and ... nuthin'. Can you suggest anything I should try before I give it up and go back to my Boss GT-6?

[myles_rose]

Originally posted by Steevo:

Hi Myles, just a quick question. I finally got my hands (ears) on a '65 Fender Champ ... looks all original ... sounds like shit. Maybe I'm expecting too much but from all I've read this little guy should sound pretty good. I'm playing my 2002 Gibson 356 through it, and it's just ... well, disappointing. I wanted it to be all tubey and swirly and have my notes 'bloom' and ... nuthin'. Can you suggest anything I should try before I give it up and go back to my Boss GT-6?

Steevo ....

 

I would first pop in a new 6V6 and 12AX7.

 

If this does not make it all better then the speaker needs to be checked. I would also check the voltages on the plates of the preamp tube and the output tube or have a tech do this. It is fast and easy for a tech. If you are near Los Angeles I would be happy to do this for you for nothing.

 

They are pretty darn cool amps.

[Steevo]

Thanks for the info and the generous offer ... however, I'm in KY. I could probably measure those voltages myself. I've got 'The Tube Amp Book' by Aspen Pittman and its got all the schematics in there. S.

[Mike1959]

Hi Myles,

 

I thought Id give you an update on the ailing Nomad. Spoke with the Mesa tech today. He hasn't finished his inspection yet but he was able to tell me what he had found so far -

 

The opto-circuits are blown. He said these components should last forever; they don't generally go unless, as he put it, 'the amp has had a hi-voltage up it's backside'.

 

As a result of the problems with the opto-circuits, channels 2 and 3 have channel 1 superimposed over them (I think that's the word he used).

 

There is a 100Hz ripple that's very prominent in channel 2 - that's the low level modulation that I was complaining about.

 

He also said that someone had botched a replacement electrolytic replacment. That is most likely the previous tech's handy work. Whilst I don't think he caused the problem, he assured me he had worked on Nomads before. He said he had repaired another clients amp, and he was very impressed with his work. I am very unhappy that he claimed to be able to service Mesa amps, but clearly didnt know how to either analyse the circuit and determine the problem, or replace components correctly.

 

There is a possible short in the circuit somewhere. He is now awaiting some photos of the circuit boards from Mesa USA for comparison. He said sometimes you can zap the bridge with high voltage.

 

AND THAT'S THE GOOD NEWS. If the PCBs are beyond repair, replacements are not available and the cost of repairing would be prohibitive, as in 'build an amp from scratch'.

 

Once he has finished the inspection, he will supply me with a report and photographic evidence. If the amp cannot be repaired within reasonable cost, I will contact either the seller or the other technician, or both, depending on his findings. As it stands now it is not good. Ive spent £700 on the amp, and a further £200 for the service.

 

Excuse me while I go and drown my sorrows

 

Mike