model t questions

[Ryanx]

see like i said in another thread, here's somewhat of what i have going on.


i have mismatched tubes.  they're all 6550, and that's what i got in them.  3 Ruby belled out tubes and one unmarked straight tube round out the power tube section.  the preamp tubes are running 2 ruby 12ax7 and one nos GE 12ax7.

i run my settings at


brite=7/8  normal= 7/8  bass=9/10  midrange=5  treble=8/9  presence=9/10

i run the master in between 3 and 5 at practice.  i also run out of the bridged input.

even at low volumes it's distorted.  i never get a clean tone.  i don't know how much i'd really want one though obviously by the title of this thread but i'm looking to JoeArthur or Issac to help me see what may be up, beings this defeats everything i've ever heard about the model t's.


i've had it at different settings with relatively the same result.  it's odd.  i'll be posting an mp3 later of just my model t through my 412srs with these settings.

[Isaac]

I start with everything on zero. That's usually the flattest response. Turn up the volume, then add a little bass, treble or midrange, usually one at a time, to see how they react.

Joe, I'm surprised you didn't call me on this.

What I wrote above is true of the first generation Model T, but not the second. The second generation uses a boost/cut circuit for the bass and treble, called a Baxandall circuit. For this circuit, the flattest response is usually with the controls set at 5. The midrange control is a boost only control, so its flattest response is at zero.

So, with a first generation T, I'd start with everything on zero, and turn each up, one at a time, to hear what effect it had. Then, I'd start playing around. With a second generation, I'd start at 5-0-5, and proceed accordingly.

[JoeArthur]

see like i said in another thread, here's somewhat of what i have going on.


i have mismatched tubes.  they're all 6550, and that's what i got in them.  3 Ruby belled out tubes and one unmarked straight tube round out the power tube section.  the preamp tubes are running 2 ruby 12ax7 and one nos GE 12ax7.

i run my settings at


brite=7/8  normal= 7/8  bass=9/10  midrange=5  treble=8/9  presence=9/10

i run the master in between 3 and 5 at practice.  i also run out of the bridged input.

even at low volumes it's distorted.  i never get a clean tone.  i don't know how much i'd really want one though obviously by the title of this thread but i'm looking to JoeArthur or Issac to help me see what may be up, beings this defeats everything i've ever heard about the model t's.


i've had it at different settings with relatively the same result.  it's odd.  i'll be posting an mp3 later of just my model t through my 412srs with these settings.

I'm confused. You first wanted to boost the gain cause you didn't think you were getting enough distortion, now you are complaining about... distortion?

Your channel volumes are way too high for a clean sound.  Put your master on 10 and keep the channel volumes low. Most T's will go somewhere between 2 1/2 to 3 clean on the channel volumes. Above that, the channel volumes are pretty much just mixing shades of distortion all the way to 10.

What's a 412srs? Have you got the impedance selector set to whatever the cab's impedance is?

[Isaac]

The 412SR is a 4x12" PA column. See Ryanx's "What I've got going" thread for a photo.

[Ryanx]

see like i said in another thread, here's somewhat of what i have going on.


i have mismatched tubes.  they're all 6550, and that's what i got in them.  3 Ruby belled out tubes and one unmarked straight tube round out the power tube section.  the preamp tubes are running 2 ruby 12ax7 and one nos GE 12ax7.

i run my settings at


brite=7/8  normal= 7/8  bass=9/10  midrange=5  treble=8/9  presence=9/10

i run the master in between 3 and 5 at practice.  i also run out of the bridged input.

even at low volumes it's distorted.  i never get a clean tone.  i don't know how much i'd really want one though obviously by the title of this thread but i'm looking to JoeArthur or Issac to help me see what may be up, beings this defeats everything i've ever heard about the model t's.


i've had it at different settings with relatively the same result.  it's odd.  i'll be posting an mp3 later of just my model t through my 412srs with these settings.

I'm confused. You first wanted to boost the gain cause you didn't think you were getting enough distortion, now you are complaining about... distortion?

Your channel volumes are way too high for a clean sound.  Put your master on 10 and keep the channel volumes low. Most T's will go somewhere between 2 1/2 to 3 clean on the channel volumes. Above that, the channel volumes are pretty much just mixing shades of distortion all the way to 10.

What's a 412srs? Have you got the impedance selector set to whatever the cab's impedance is?

you're always coming down on me.   

i wasn't complaining, just not giving into what my story was 100%.

the model t is fine for me, but for what we needed at the time on our record, it wasn't, i needed more out of it, it worked out that we used a Marshall Jubilee because my T hadn't shown up yet.   I'll play more with it on Monday, i'm running 4 ohms into it so it should be going well.  i'm going to take it home and record different settings.  not really to locate an issue, just to give people some ideas on how it sounds.

[JoeArthur]

you're always coming down on me.   

i wasn't complaining, just not giving into what my story was 100%.

the model t is fine for me, but for what we needed at the time on our record, it wasn't, i needed more out of it, it worked out that we used a Marshall Jubilee because my T hadn't shown up yet.   I'll play more with it on Monday, i'm running 4 ohms into it so it should be going well.  i'm going to take it home and record different settings.  not really to locate an issue, just to give people some ideas on how it sounds.

All you have said is that you don't like the sound. I don't know what you were told or what your expectations are, and it seems that your expectations are doing flip-flops. Be a bit more specific.

This is what I think I understand so far. Please feel free to correct any misunderstanding I might have:

o You bought a 34 year old amp off of ebay. You know nothing about the history (repairs, mods) of the amp.

o There is a smorgasbord of tubes in the amp. One of the output tubes is unknown, but there is hope it's a 6550. The age of the tubes is also an unknown.

o You haven't taken the amp to a tech. The power tube bias is unknown. The condition of the electrolytic caps is unverified. The supply voltages are unknown. The circuit has not been confirmed to be original.

When you purchase an old amp - from anywhere - there is no basis for an expectation for the amp to perform "as new".

At a bare minimum, especially for a tube amp from ebay, it is pretty much 100% certain that the tubes need to be replaced. 80% plus of all tube amp problems are caused by the tubes.

Electrolytic caps and other parts don't last forever. Electrolytics in particular can have a short life if the amp isn't used very often. Using the amp frequently extends the life of electrolytics. If the amp has been stored for a period of time, it is usually 100% certain the electrolytics need replacement as without a voltage on them frequently, they will dry out.

The bias needs to be checked because it may have been modified in persuit of that elusive ultimate tone.

And last but not least, the amp may have been "abused" and suffered some damage that has not been repaired. The plate fusible resistors is a good example. If these are blown, you will essentially lose the tube it is connected to - and you may be completely unaware that this has happened as the reduction in power is usually not enough to notice. Depending on which tube or how many tubes, you can get distortion at most volume levels.

One quick check you can do to check the plate resistors is to power up the amp (with speaker connected as always of course) and look at the power tubes in a darkish room. Flipping the standby switch to the operate position should produce a noticeable blue glow inside the glass envelope of all output tubes.

If this blue glow is "excessive" it usually means the tube needs replacement. If the blue glow is non-existant, it can mean a bad tube or the plate resistor is blown. If you switch the tube that doesn't glow with one that does and the tube now has a glow in the new position, and the one that did glow now doesn't, there is a high possibility that the plate resistor is blown.

Sorry that the amp doesn't meet your expectations - but until you verify that the amp is in full operating condition... as I said before, you really have no basis for any expectation.

[giovanni]

man, run that thing mid heavy.    roll off the bass and treb. 

 my band recorded the other day and the guy who owned the studio couldn't believe how much my t killed the sound of his graphic or120.   that and when my buddy came over with his '73dr103, called by some, the greatest amp built, and my model t/sunn412/hiwatt412 setup smoked his two orange412 hiwatt setup.

mind you, i have a second gen with the mid switch.   i'm all about my second gen.   i did however play a first gen t awhile ago and it wasn't for me.   

they're fucking great amps.

[Johann]

I thought the other guy in your band is using a second gen Model T as well Justin.



John - owner of the first gen model t and your old 412LH 

[Ryanx]

you're always coming down on me.   

i wasn't complaining, just not giving into what my story was 100%.

the model t is fine for me, but for what we needed at the time on our record, it wasn't, i needed more out of it, it worked out that we used a Marshall Jubilee because my T hadn't shown up yet.   I'll play more with it on Monday, i'm running 4 ohms into it so it should be going well.  i'm going to take it home and record different settings.  not really to locate an issue, just to give people some ideas on how it sounds.

All you have said is that you don't like the sound. I don't know what you were told or what your expectations are, and it seems that your expectations are doing flip-flops. Be a bit more specific.

This is what I think I understand so far. Please feel free to correct any misunderstanding I might have:

o You bought a 34 year old amp off of ebay. You know nothing about the history (repairs, mods) of the amp.

o There is a smorgasbord of tubes in the amp. One of the output tubes is unknown, but there is hope it's a 6550. The age of the tubes is also an unknown.

o You haven't taken the amp to a tech. The power tube bias is unknown. The condition of the electrolytic caps is unverified. The supply voltages are unknown. The circuit has not been confirmed to be original.

When you purchase an old amp - from anywhere - there is no basis for an expectation for the amp to perform "as new".

At a bare minimum, especially for a tube amp from ebay, it is pretty much 100% certain that the tubes need to be replaced. 80% plus of all tube amp problems are caused by the tubes.

Electrolytic caps and other parts don't last forever. Electrolytics in particular can have a short life if the amp isn't used very often. Using the amp frequently extends the life of electrolytics. If the amp has been stored for a period of time, it is usually 100% certain the electrolytics need replacement as without a voltage on them frequently, they will dry out.

The bias needs to be checked because it may have been modified in persuit of that elusive ultimate tone.

And last but not least, the amp may have been "abused" and suffered some damage that has not been repaired. The plate fusible resistors is a good example. If these are blown, you will essentially lose the tube it is connected to - and you may be completely unaware that this has happened as the reduction in power is usually not enough to notice. Depending on which tube or how many tubes, you can get distortion at most volume levels.

One quick check you can do to check the plate resistors is to power up the amp (with speaker connected as always of course) and look at the power tubes in a darkish room. Flipping the standby switch to the operate position should produce a noticeable blue glow inside the glass envelope of all output tubes.

If this blue glow is "excessive" it usually means the tube needs replacement. If the blue glow is non-existant, it can mean a bad tube or the plate resistor is blown. If you switch the tube that doesn't glow with one that does and the tube now has a glow in the new position, and the one that did glow now doesn't, there is a high possibility that the plate resistor is blown.

Sorry that the amp doesn't meet your expectations - but until you verify that the amp is in full operating condition... as I said before, you really have no basis for any expectation.

now you're putting words in my mouth.  the only thing basically i don't know about are caps.

[JoeArthur]

now you're putting words in my mouth.  the only thing basically i don't know about are caps.

I'm not putting anything in your mouth. I believe it was you that said this:

i have mismatched tubes.  they're all 6550, and that's what i got in them.  3 Ruby belled out tubes and one unmarked straight tube round out the power tube section.  the preamp tubes are running 2 ruby 12ax7 and one nos GE 12ax7.

Maybe what you said was not what you meant, but if you aren't willing to clarify, excuse me for not being able to read your mind.

[giovanni]

ah john, how  have you been, those  eminences holdin up nicely in that 412?   shit i could've used those a couple months back, but got v30s for my cab instead.   Have you retubed that T or what?  Also i want that beta, name your price.   AAAaaaaaaaaaaAAAnd, we don't practice there anymore but if you wanna hear some stuff we've been up to lately, check it out...


http://boomp3.com/m/9f5d390637a9

[giovanni]

BTW, that guy,(aaron) left and moved to portland along with his second gen t, his dr103, his orange cabs and his red bear, which he traded for a soundcity120r.   fuck, that guy has a lot of gear, and he's nineteen.   last i heard he was trading his cabs and the hiwatt for two silver cloth ampeg eight tens or some shit.  jesus.


OH and my model t destroyed his dr103, that amp was way overrated, hell greg's mig100 kills that amp as far as i"m concerned, aaron never admit this, but we all know it to be true.

[Johann]

haha, yeah the eminences are great. I still need to fix my Beta before I think about selling it, I bought it for the cab really and still haven't got around to taking it somewhere to get it fixed.


and I still need to retube my T, I just haven't really been using it lately since I've been using a concert lead instead