Dr Z Route 66, tube replacement

[hylo]

Hi guys!

I have a Dr Z Route 66 which is REALLY awesome. It's loud and kicks some serious ass, but one of my bandmates has a Matamp GT40. Which can pump out a little bit more. I don't mind that at all - when we play loud I bring out my '72 Hiwatt DR103. But I need a little bump in the headroom-department on the Route 66. Not a lot, just a little touch.

If I change over tubes from KT66s to 6L6s, will it increase headroom slightly? Or am I better off trying out other KT66's?
Any ideas?

I'm pretty new to the whole changing out tubes (to other tubes that may fit). Is there any good resources online to get a bit of education on the subject?

 

[Steppin' Wolfe]

Speakers do more for that headroom thing than anything else, ime.

 

[71strat]

Yeah speakers will make the biggest SPL increase.

What speakers are you using ? A 3db increase in db is = to doubling your wattage.

 

[Steppin' Wolfe]

Yeah speakers will make the biggest SPL increase.

What speakers are you using ? A 3db increase in db is = to doubling your wattage.

Actually, to double volume through the same speaker one would have to increase power output by 10 times.
Doubling the power output...wattage.....is a barely perceptible change. That is why I suggested an increase in speaker efficiency is the easiest way to increase volume. A 3db change is very perceptible....a 6 db increase in efficiency is like going from a 10 watt amp to a 100 watt amp.

 

[lostpoet2]

Are you running a 12ax7 as your phase inverter tube? If so, a 5751 is a popular alternative for increasing headroom.

 

[Tone Meister]

Yes, speakers for sure.

Another thing to consider: not sure if that amp is a candidate for a solid state rectifier. I know the difference is night and day in my KT45 between the 5AR4 and a solid state rectifier.

That would be something worth looking in to as well.

 

[hylo]

Speakers do more for that headroom thing than anything else, ime.

I'm using a Hiwatt (Maxwatt-copy) 412 cab. Haven't found out much about the speakers (hiwatt-branded), since they actually sound very good. Especially through a crancked Dr103.
Maybe get a new cabinet with more efficient speakers, then. Greenbacks and JTM-ish tones must be awesome.

Are you running a 12ax7 as your phase inverter tube? If so, a 5751 is a popular alternative for increasing headroom.

I'm already using a 5751.

 

[Steppin' Wolfe]

IMho, a 12AT7 is more appropriate for the phase inverter position than is a 5751. 12AT7/12AU7 tubes were designed for driver positions whereas the 12AX7/5751/12AY7 tubes were designed for tone generation/preamp positions. And...decreasing the gain by changing a tube to a lower gain tube is a questionable way to go about increasing headroom, ime. IF that is the goal, just turn the volume or preamp gain down....or turn the guitar down. Lower gain tubes do NOT increase headroom....they just move the point where the max clean headroom is achieved to a different point on the gain/volume control. MAGIC!!!! But...it ain't real.
One also might wonder how this amp is biased? One could decrease the size of that bypass cap on the EF86 to change things especially if the lower freqs are what are going into distortion earlier than you would like. ....or put it on a switch as a 'gain boost' when wanted.
I had one of these DR.Z Rte. 66 amps on the bench a couple of weeks ago. IT is an odd map inthat the schematic doesn't look a lot like a 5F6A Bassman/early Marshall, but it surely does sound like one to a great extent. They don't do BF Cleans, that is for sure.

http://www.prowessamplifiers.com/schematics/misc/Dr_Z_Route_66_-Schematic.html

Question, hylo, have you ever run this Dr. Z amp through the speaker/s that the Matamp is running through just to compare what difference there is there? These two amps should NOT be worlds apart in output when run through the same speakers, I would guess. Schematics for modern Matamps are like schematics for modern Orange amps in that they are very hard to come by. So, it is difficult to understand how different the two amps are.

 

[Tone Meister]

I will again suggest looking into a SS rectifier. It will raise internal voltages and that will increase headroom. A quick call to Mike at Dr Z and you can verify if a SS rectifier is ok to use with that amp. The headroom in my KT45 increases dramatically with a SS rectifier as opposed to the GZ34.

A $15 rectifier and a quick rebias would certainly be an efficient solution, if it will work with that amp.

 

[hylo]

IMho, a 12AT7 is more appropriate for the phase inverter position than is a 5751. 12AT7/12AU7 tubes were designed for driver positions whereas the 12AX7/5751/12AY7 tubes were designed for tone generation/preamp positions. And...decreasing the gain by changing a tube to a lower gain tube is a questionable way to go about increasing headroom, ime. IF that is the goal, just turn the volume or preamp gain down....or turn the guitar down. Lower gain tubes do NOT increase headroom....they just move the point where the max clean headroom is achieved to a different point on the gain/volume control. MAGIC!!!! But...it ain't real.
One also might wonder how this amp is biased? One could decrease the size of that bypass cap on the EF86 to change things especially if the lower freqs are what are going into distortion earlier than you would like. ....or put it on a switch as a 'gain boost' when wanted.
I had one of these DR.Z Rte. 66 amps on the bench a couple of weeks ago. IT is an odd map inthat the schematic doesn't look a lot like a 5F6A Bassman/early Marshall, but it surely does sound like one to a great extent. They don't do BF Cleans, that is for sure.

http://www.prowessamplifiers.com/schematics/misc/Dr_Z_Route_66_-Schematic.html

Question, hylo, have you ever run this Dr. Z amp through the speaker/s that the Matamp is running through just to compare what difference there is there? These two amps should NOT be worlds apart in output when run through the same speakers, I would guess. Schematics for modern Matamps are like schematics for modern Orange amps in that they are very hard to come by. So, it is difficult to understand how different the two amps are.

Wow, I actually learned a lot from that post. Thank you!

Maybe I should get a hold of a 12AT7 and try that one out for the inverter. I really don't know how the amp is biased. Traded the amp for some other stuff, so it's basically bone stock (as far as I know). It also sounds awesome imho! We usually play pretty loud when we're rehearsing (we're lucky enough to rehearse in a place where that's actually possible without disturbing anyone), so I'm basically cranking the amp all the way and clean the amp up with my guitar's volume. The distortion from the amp all the way up is pure fun.

Haven't tried the amp through a different cab just yet. I'm thinking of getting a 412 with high sensitivity speakers to see if that helps some.
The Matamp and the Dr Z is different in a lot of ways it seems, master volume, boost and gain control on the Matamp compared to volume, treble and bass on the Dr Z and a different tubes in the output section of the Matamp.

 

[Steppin' Wolfe]

hylo, I tried to find some sort of clues as to the circuit in the MATAMP..... Without that info, it is difficult to understand how to compare the two amps. A change of rectification will change what goes on in that DR Z., but the change will be on the order of maybe 10 watts.....and 10 watts does not change much IF a radical increase in output is being sought. "Yes, the voltage change will rebias the preamp and chane what goes on there. But.....that Z amp seems to act like a 5F6A in that there is some preamp gain going on that is hard to avoid. That EF86 tube must put some voltage out. Others surely have more experience with that aspect of that amp than I do.
But.....if I had DR103, I would never worry about someone overpowering my guitar. that amp will convince anybody that a battle of power is a negative approach to playing music with other people. (;^)

 

[hylo]

Tbh a radical increase in output isn't what I'm looking for. Either way, played through it today and it works really great in a typical rock setting. The amp actually sounds the best when all the controls are wide open IMO. It has that awesome bf/marshall tone without the insane volume.

The hiwatt really rocks, but it also is too loud when it sounds the best. Its an absolute monster. Here's a picture of that old dr103 if you're interested.