I am curious whether anyone has tried a KT-45 with a tube rectifier, and how it sounds in general, and how it sounds compared to the KT-45 and Rt-66 clips I can find on the site or elsewhere on the net?
FWIW I have a 6545 with a 5AR4 and I love it. I could say it's warm and soft, maybe like a rubber sledgehammer just out of the microwave.
This is my "big" amp and I wouldn't part with it under any concievable circumstance. I think the 6545 "clean humbucker" clip on the proguitar site may be a bit more...ummm....relevant (http://proguitar.de/AudioDemo/CompareAmps/CompareAmps.html). The DRZ site clip sounds great, but I have a sneaking suspicion there's more than just KT45 in that clip. Do you have access to a dealer or an amp to check out?
Mine also came with a 5AR4 or GZ34, not a SS like it is listed on the website. I am actually interested to either buy a NOS Mullard or try a SS just too see how mean this thing can get! Either way, I dont think you can go wrong.
Does anyone out there like SS rectifiers? I hear many views on this matter supporting both sides. Many say SS gives you more headroom. Perhaps just a personal preference issue
Dr. Z Carmen Ghia 25th Anniversary Head
Dr. Z Prescription head
Jamie, I don't think you'd notice a difference in the tone of the amp, since the rectifier isn't in the tone-shaping part of the circuit. The noticeable difference is in the sag/ feel. Also, some newer tube rectifiers don't have a great record of sturdiness. So a nice NOS tube may be a good idea.
I think for my KT45 and several others, it might be worthwhile to stock up on some NOS Mullard GZ34s! ;D
One thing about NOS rectifiers ... there is no need to stock up as rectifiers do not wear out, they just fail. But .... NOS ones last for decades. I cannot begin to count how many early sixties amps I take care of such as Vox AC30s .... which run very hot and are hard on tubes yet most have the original rectifiers. Same thing for a few Marshall JTM45s and Bluesbreakers. All you might need is two ... one in the amp and the other in case the amp falls off the stage and the rectifier physically breaks.
Post by Phil (aka Phil) on Jul 20, 2008 6:02:32 GMT -7
I can answer this question. Two days ago I traveled to Cleveland to do some photography for Michael Bay (I can post some of those pics if you want to see them ). I also was going to stop by the Doc's shop and pick up my Route 66 that I dropped off for its 50,000 mile checkup at Z-Fest.
While I was at the shop I got the opportunity to play my favorite Z amp, the KT45. Doc had his two amps from Z-Fest (one tube rectified, one solid state) at the shop. I also had my newly freshened up Route 66 for comparison. I had previously only played a tube rectified one; I was looking forward to the test.
I played all three amps through a Z-Best with my Grosh Strat and Room Mate reverb pedal. When I started the test, I was 100% sure that I would like the tube rectified one better. I mean, doesn't everyone like those nice tube rectified amps? ;D I plugged into the tube rectified one first. My initial reaction: fantastic clean sounds. It has the percussiveness of a Rx or RxES. The bass was very tight, and always "under control". The mids are very "flat" for a Dr. Z amp; this is the perfect amp to run with pedals- especially modulation pedals. It has sweet mids but they're not as forward as something like a Route 66 or the EL84 amps. The treble control has as many highs as a RxES- I usually run the treble controls up on my Z's but this amp sounds great at 3:00 with more to spare (my Grosh has Fralin Vintage Hots in it). I turned it up over 12:00 on the volume and it just kept getting better and better. The highs get that "EL34" kind of crushed glass treble, but the amp always keeps it's "character" and the lows remain nice and tight.
I then plugged into the solid state rectified one. Brent hit the standby switch, I hit the beginning of "Little Wing" (SRV version) and BAM- there it was - the tone I've been looking for forever. My style is sort of a cross between Jimi, Steve, Trower, Knopfler, Johnny A and a bunch of other stuff thrown in. I want an amp that has a great clean sound; the bass *never* gets mushy or soft, the highs gets crunchy as you really dig in, lots of articulation, and great harmonics. The solid state rectified one was never ever harsh but does exactly what I just said. Compared to the tube rectified one, it was about 20% louder, the bass was even tighter (so much I laughed out loud). The amp sounds like it has a death grip on the speaker cones- we geeks call that a high damping factor. It feels like your fingers are connected right to the speakers in a way that even the Mazerati GT can't quite duplicate. I thought at the time that this would make an incredible bass amp. The highs, articulation and harmonics were increased as well. It had more "bandwidth" frequency wise. Power tubes sound differently at higher and lower voltages and you could immediately hear the difference in the two amps (the solid state rectified one will have a slightly higher plate voltage).
After I wiped the drool off my face we plugged in the Route 66. It sounded like it could have been made on a different planet- it was that different than the KT's. The attack is much softer; more like a fist hitting a pillow versus the KT45's hammer hitting an anvil. The KT has more highs than the 66 can dream of- the 66 is a much smokier amp. The mids on the 66 are extremely prominent, while the KT's are flatter and more "hi fi". The bass on the 66 is great, but it's got a nice attack (kind of like the Ghia's) where the KT's is very immediate. Both KT's were louder than the 66.
The cool thing about the KT is that it sounds great at low volumes too. It just gets better and better the more you turn it up. I think SRV would have fallen in love with the solid state rectified KT- it can do that sound at higher volumes. The lower volume sounds can, as Myles has said, cover the Fender 6L6 sounds beautifully. How the Doc pulled that off I'll never know.
A little bird told me that the KT is going back into production this fall.... ;D
Post by Phil (aka Phil) on Jul 20, 2008 10:34:00 GMT -7
Matt - I didn't get the KT's up into the real "crunch zone" - which is up around 3:00 and above on the volume knob and tone knobs with either amp out of respect for Amy, who was in the room listening. It was loud enough already at the highest level I tested them (treble at 3:00, bass at 1:00 and volume at 1:00). With the single coils in my Grosh that was about the place where the treble had a lot of "hair" on it. I didn't have a humbucker equipped guitar with me to try.
Brad - a tube rectifier has a voltage drop associated with it that a solid state rectifier does not. Substituting a solid state rectifier for a tube will make your plate voltage higher, and have a faster rise time, which subjectively will cause an amp to be brighter, louder, have tighter bass, and a more "immediate" feel. The 20% figure was a ballpark figure; I know the solid state one was noticeably louder (Amy noticed that too) but it's not twice as loud or even half again as loud; it's more like 20-30% louder.
Thanks for the info, Phil. I'd never heard about that before. A rectifier swap could be a neat little trick for times your rig just doesn't cut through enough. Although I don't play out, and can't imagine a place where a KT wouldn't be loud enough.
Post by Phil (aka Phil) on Jul 22, 2008 6:41:48 GMT -7
My understanding is that the when the KT goes back into production in the fall that it will not be a "LE" model. It's going to be exactly like it was; a full production model.
The good news is that from my testing, the KT sounds *great* at low volumes. The overdriven EL34 "clang" only happens at high tone and volume control settings though. I don't want (or pretend) to speak for the Doc but I think that the "28/66/45/88" circuit needs the full drive from the phase inverter to sound good and would not be a good candidate for a master volume. I think the way to go with the KT is less efficient speakers (i.e. Greenbacks) and an Airbrake if necessary.
Having said that, I *love* it with a Z-Best. It's a little loud, but what a sound....
Is the tube rect swappable with a SS Rect or is the SS hardwired?
It's swappable. The solid state rectifier is a plug in socket type. You have to re-bias the amp though.
Actually .... the voltage does not change that much ... maybe 10-15 volts so you will only see about a 1-2mA change at the most.
Going from 450B+ to 475B+ only changes the bias by about 1mA as an example.
Bias for one or the other anywhere between 50% and 60% ID (to your own taste) and at that point you can swap back and forth depending on you feeling for that particular day Plug and play so to speak.
The lower picture is an old shot of Brad Paisley's rig few years ago in he Zac Childs era pre Chad Weaver era.
The black 88 and the brown 45 are my amps. The 88 was there to test against his red one where in the end his red one had the bias changed dramatically. We were also trying it with Randall (his pedal steel guy) to see how it would sound.
The 45 was there to compare to Gary Hooker's KT-45 which was his main amp at that time. Prior to the KT-45 Gary used a Z-28.
Post by Phil (aka Phil) on Jul 22, 2008 15:14:16 GMT -7
Yeah, I guess "have to re-bias" was a little strong. ;D I'm anal (who, me? No!) - I always check the bias and the plate voltage when I make changes like that even though unless you're running right at the edge and it's a couple of mA higher you'll be fine.
Heck, sometimes I check the bias when I change out my GT's with the same rating tubes... I'm either anal or I have too much time on my hands (NOT!) ;D
Sorry, I've been away for awhile and missed this. No, I went with the Groove Tube: GT-SS-5AR4/GZ34(Solid-State)
BTW, Was it announced that the Doc is bringing back the KT-45? I've seen posts refer to that info but must have missed the announcement? Would the new model be any different than the original? Heck, I went and acquired three KT45's (including the 6545) over the past few months thinking they were put to rest!
Post by cashandkerouac on Jul 22, 2008 23:15:02 GMT -7
i'm surprised to see so many people liking the SS rectifier with the KT-45. unless your able to really get the KT-45 into the sweetspot (sans Air Brake), i think the SS rectifier makes the amp sound a little steely and cold. i sure don't have the type of situation where i can run the KT-45 full out without an Air Brake, and to my ears the tube rectifier gives the amp more life and responsiveness at lower volumes.