PPIMV ?

[Doug H]

There were lots of gigs where my little deluxe was a little too loud for the first set, but not quite enough for the third, it was a real aggravation.

For me, the answer to that is small amp - big p.a. Haha!

What's funny is how Trainwrecks are sort of a product of their era, like most amps. The guitar player review that compare three different amps including the TW treated it like it barely had enough power. Nowadays, people recognize that 30 watts is a *lot* of power.

[geetarpicker]

I probably the minority to believe an attenuator with a Wreck is my prefered way to tame it down. I usually prefer a THD over my Airbrake. It seems the Airbrake is brighter than the THD and that is something that the Wrecks really don't need any more of.

As much as a smaller powered amp make sense, it seems that once you have smaller iron the low end just isn't the same...

I think a big part of the "feel" with a Wreck is the power supply sag, something that doesn't happen with a master volume. I also wonder if a power scaling circuit can emulate that effect? The sag in the power supply IMHO helps the amp to compress when pushed, but open back up when backed off. In performance this evens out the volume and allows the amp to go from "clean to scream" with very little actual volume change. At least that's my take on it. Maybe power scaling can capture this sag effect? It seems all the masters I've heard really hurt the clean headroom in relation to the dirty volume.

I remember Ken Fischer mentioning a response he heard from Eric Johnson about playing a Liverpool back in the day. Apparently Eric said it was the "best practice amp he had ever played", as in not loud enough for his stage use. That said these days Eric does have tinnitus, though I heard he is back to 100s for his lead tone after going to smaller amps for a while. Maybe he wears earplugs these days?

[drhulsey]

Master volumes are for pussies!

I am so privileged to play in a nine piece band with a LOUD drummer. I get to run my Express clone about as loud as I want

... Eric does have tinnitus... Maybe he wears earplugs these days?

Or great big earphones like on the G3 Tour I heard that Satch and Vai complained about Johnson being TOO LOUD

... We have had people try power scaling the output and PI section and the MV on the express and I don't remember anyone giving it rave reviews...

Dana, have you tried the VVR with Wreck I haven't seen as much about it here as on 18watt.com.

[Buschman]

I just love the 1st set to 3rd set analogy. That's how it is. Not looking for miracles here, just a bit more versatility without killing the tone we are working so hard for. I also think my ears change once the volume goes up or you have been playing for 2 hours.

[UR12]

... We have had people try power scaling the output and PI section and the MV on the express and I don't remember anyone giving it rave reviews...

Dana, have you tried the VVR with Wreck I haven't seen as much about it here as on 18watt.com.

I have it installed in the Liverpool/Rocket amp but I am still evaluating it. The biggest problem with scaling an Express is getting around scaling the bias to track with the B+ voltage. I have a new circuit in the works that does just that. It's a new board that I will make available to the public soon. I converted the Liverpool/Rocket amp over to Fixed bias and have the new board installed. I am scaling the whole amp and not just the power tubes so it is a little trickier. I am pretty pleased with the results so far but I will reserve my opinion until I hear it in an Express.

I think that the gain structure on the TW amps is a litttle different than most. IF your amp distorts the power tubes first and the rest of the amp later on the vol control then adding a master vol will kill the power tube distortion, which IMO will kill the gain structure. Same thing with Power Scaling the power tubes only except that will do just the opposite unless you add the PPIMV. By scaling the whole amp you should be able to keep the gain structure the same accross the board. Something you can't do with just a MV. Here is a sneek peek of my new board. It's not available yet but I will post it in the for sale section here when I have them ready to go.

[Clyde]

Although not a 'Wreck, I did a JTM 45, whole amp scaled and it sounded pretty good. Although Kevin O suggested just the power section or the PI also when I talked to him, I didn't have the real estate for the drive compensation (MV) control nor the extra board with the extra filter caps.
If I did it again, I'd go whole amp even though I haven't heard it the other way; it seems just fine.

[Lonely Raven]

Dana, that looks great! Doesn't look to difficult to install, even for a noob like me.

Keep us informed! Especially if you feel it will work on the Express!

[gearhead]

IF your amp distorts the power tubes first and the rest of the amp later on the vol control then adding a master vol will kill the power tube distortion, which IMO will kill the gain structure.

Is there a sure fire way to tell/ensure that a particular Express build -is- distorting at the PTs first?

[UR12]

Just put it on a oscilloscope, feed it a clean sinewave and crank the vol monitoring the diffferent sections of the amp to see which one distorts first.

[gearhead]

I was afraid you were going to say that, LOL.

Note to self; put another tool on the list.

If the preamp/PI is distorting first, would you drop the B+4 and 5 by increasing the 9k1?

[RHGraham]

I probably the minority to believe an attenuator with a Wreck is my prefered way to tame it down. I usually prefer a THD over my Airbrake. It seems the Airbrake is brighter than the THD and that is something that the Wrecks really don't need any more of.

As much as a smaller powered amp make sense, it seems that once you have smaller iron the low end just isn't the same...

I think a big part of the "feel" with a Wreck is the power supply sag, something that doesn't happen with a master volume. I also wonder if a power scaling circuit can emulate that effect? The sag in the power supply IMHO helps the amp to compress when pushed, but open back up when backed off. In performance this evens out the volume and allows the amp to go from "clean to scream" with very little actual volume change. At least that's my take on it. Maybe power scaling can capture this sag effect? It seems all the masters I've heard really hurt the clean headroom in relation to the dirty volume.

I remember Ken Fischer mentioning a response he heard from Eric Johnson about playing a Liverpool back in the day. Apparently Eric said it was the "best practice amp he had ever played", as in not loud enough for his stage use. That said these days Eric does have tinnitus, though I heard he is back to 100s for his lead tone after going to smaller amps for a while. Maybe he wears earplugs these days?

Hi Glen
You start right off by saying "my preferred way"... that's the point in the end really, what works for you works for you, and that's a good thing.

I only had a brief expirience with the scaled amps but the sag didn't seem to be affected. Personally, I think any addition, to any amp, changes something, my question is always "can it be compensated for and is it worth the trouble?" Also, the powerscaling isn't really a typical master volume, and like everything else there are a bunch of ways to implement it and, like everything else, there'd be a learning curve to sorting it all out. I'm still only considering it myself, I'm not decided in which way I'm going to go as of yet.

The tinnitus issue I think could be taken more seriously by some folks, I sure wish I had of. I played loud myself for a lot of years, and did sound professionally for some time also, I now have a pretty serious case of tinnitus in my left ear, and it really, really sucks. But, I'm still a guitar player too, and I was and am a real tone whore, it's gotta be all there or don't bother, and a lot of amps, like the TW, come to life cranked, it's just the way it is. My deluxe was like that, although it wasn't super loud, but my Garnet session man was, and so was the marshalls... the quest for me now is a good way, whichever way that is, to be able to have a fundamental controll over the output without sacrificing tone to the point where it can't be fixed or compensated for. Attenuators are one way, lower power is another way, and I've looked at powerscaling and a few other methods for output power controll as well. At the very least, they are worth trying.

I still like "loud", but "controll" is a good word too.

Glen, BTW, your clips kick ass. They are partly responsible for me picking up the guitar again.

[RHGraham]

There were lots of gigs where my little deluxe was a little too loud for the first set, but not quite enough for the third, it was a real aggravation.

For me, the answer to that is small amp - big p.a. Haha!

What's funny is how Trainwrecks are sort of a product of their era, like most amps. The guitar player review that compare three different amps including the TW treated it like it barely had enough power. Nowadays, people recognize that 30 watts is a *lot* of power.

Ahh, you're right, my little deluxe got buried by my drummer in one band I was in for a long time, so we got a cool side-fill rig and added it to the rig.... that's why my left ear is buggered... and I had the mon. mixer on my side...

[UR12]

I was afraid you were going to say that, LOL.

Note to self; put another tool on the list.

If the preamp/PI is distorting first, would you drop the B+4 and 5 by increasing the 9k1?

No. You would need to experiment with the bias point and maybe the headroom. If you had a 820ohm on your cathode you could change that to a 1.5k or 2.7k. (Less gain) Lowering the voltage may make it distort quicker if nothing else changes (ie no power scaling)

[drhulsey]

... I am scaling the whole amp and not just the power tubes so it is a little trickier...

I can't wait I hope everybody appreciates the time, effort and creativity Dana put into this little board. The simplicity of its use belies the ingenuity of its design
You can read some of its history here:
http://www.18watt.com/modules.php?name= ... sc&start=0

[Fischerman]

FWIW, I built a Ceriatone Express and incorporated Power Scaling into the build from the get go. I originally only used Nik's preamp board and made the others myself using G10 and eyelets (I later replaced the preamp board because I had modded it so much ) . I used the older version of Power Scaling where you just have one variable PS and one fixed PS. I ran the power tubes off of the variable B+ and the rest of the amp (including PI) off of the fixed B+. I later tried scaling the PI along with the power tubes and leaving the preamp fixed (and used a different MV) but I much preferred not scaling the PI.

I can't say that I love that amp but I'm not sure the power scaling has anything to do with that. I've played the amp cranked and don't think it sounds that much better than scaled...but it does feedback/sing better with volume. I think it's just that an Express is the wrong amp for me. I have zero finesse with the volume control and just can't do these amps any justice...so take my lack of excitement with a grain of salt. My amp doesn't sound any different than a lot of clips on here (well...the ones that are just guitar-volume-on-10-and-play-some-ZZ Top ).

The biggest problem with scaling an Express is getting around scaling the bias to track with the B+ voltage.

I used a kit from London Power and the bias seems to track the screen B+ great. I was concerned with the post-PI MV possibly mucking with those mV-magnitude bias voltages when scaled way down so I added some isolation caps to the MV.

Glen is correct about the sag though...it won't sag anywhere near the same when scaled the way I did it.

Doesn't look so great in the pic...I've cleaned it up a little...and this was my first exposure to power scaling and the layout was entirely my own (read: it could be much improved!). MOSFET is mounted on the sidewall near the power/SB switches using the chassis as the heat sink.
[img:800:600]http://i108.photobucket.com/albums/n4/m ... tshot1.jpg[/img]