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Post by Scott on Sept 13, 2010 6:33:43 GMT -7
Thanks again! OP Updated...Just snagged some fun Jr Reverb pictures in " The Amp Guts Appreciation Thread ! !". Picture was from 02-27-2008www.thegearpage.net/board/showthread.php?t=334977&page=10Just the kind of thread where one might expect to find a Z... OP Updated! Note that the 2 Power Tubes are both shifted 1 hole to the right, -vs- the NR model. I also found this post that I like: www.ultimatemetal.com/forum/andy-sneap/248668-have-you-guys-experienced-shuguang-9th-gen-12ax7s.html Originally Posted by Steve Fryette at vhtusers.com Hi guys,
Regarding the difference between the China 12AX7s we use in production and the so-called C9 or 9th generation 12AX7, our position is that there is none other than the normal progression towards continuing improvements in quality which is always ongoing. Hence the tubes we use are the same as those designated by others as C9. None of the suppliers we use can confirm or verify that this is anything more that creative marketing on the part of some 3rd tier tube resellers.
Most likely any difference you may hear would be attributed to either normal performance variations from one production run to the next, or just the difference between a fresh tube and one with a bit of mileage on it.
I'm still prodding our suppliers to do their own research, and will post an update as soon as I get more information. Until then, our position that this claim lacks substantive documentation stands.
Based on the most recent production batches of preamp tubes we evaluated, we will continue to ship our amplifiers with the same tube complement that we have been using all along: V1 stage: 12AX7WB or V1 grade Selected Shuguang 12AX7A All other 12AX7 positions: Low Noise Selected Shuguang 12AX7A All 12AU7 or 12AT7 applications: Shuguang 12AU7 or 12AT7 Valvulator 1: 12AX7WB or JJ12AX7/ECC83 GP3 V1 and V2: 12AX7WB. GP3 All other 12AX7 positions: Low Noise Selected Shuguang 12AX7A Power amps: Low Noise Selected Shuguang 12AX7A and 12AU7.
Recently evaluated tubes: 12AX7A/7025 Shuguang Well balanced tonal spectrum, low noise with moderate microphonic tendencies, easily selected out in production. Excellent for clean and overdrive sounds.
12AX7WB Sovtek Lower gain, somewhat less bass response, and not as bright as Shuguang, but not dull sounding. Very low microphonic tendencies.
12AX7A Tung-Sol Very good gain and low microphonics. Nice low end. Somewhat forward in the upper mids. Basically a fatter higher gain EH 12AX7. Appears to be an EH with a different getter.
12AX7 EH Very good gain and low microphonics. Less low end than Tung-Sol and not as smooth on top. More pronounced in the upper mids.
12AX7LPS Sovtek Similar to the EH but generally a little less of everything. Nice balance and a good alternative to the Shuguang if you like less top and a little more mid.
12AX7/ECC83 JJ Works well in Valvulator 1, which was surprising, since it did not fare as well in prior testing. Apparently the hum and microphonic issues have been addressed. A little darker sounding than the WB. When used in the amplifier V1 stage, this tube performs similarly to the WB, but the mids are more pronounced, the top end is dullish and overall somewhat harsh sounding for high gain settings.
Hope you find this useful...
smf
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Post by benttop (Steve) on Oct 12, 2010 9:23:32 GMT -7
Numerous Maz Jr. owners love how the Dr's 2x10 Cab, with the Dr's custom speakers sound with their amp. Me included. The Dr's 10" speaker efficiency rating is 96.7 db at 1w/1m. Theoretically, the 2x10 Cab's total volume should be rated at 99.7dB at 1 watt/meter. 96.7dB to start... Double the surface area for using two speakers (+3dB) = 99.7dB Total.Fabulous job on your Maz details, but there is one problem with the statement above (which, by the way is a very common perception): Check this message for Ted Weber's take on multiple speakers and efficiency: drzamplifiers.proboards.com/index.cgi?action=gotopost&board=xperts&thread=11512&post=146561. I'm glad that Ted posted this before he passed away - it has helped me innumerable times. Based on Ted's advice, two ten inch speakers would be the same as one 14.14 inch speaker.
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Post by Scott on Oct 12, 2010 11:08:50 GMT -7
Thanks... Outstanding post for sure! No question, the man knew his stuff... Posted by tedweber:
Whew... how much time do you have? ;D
For starters, two speakers sitting side by side share the same angles of radiation of the sound, (called subtended angles). So, together, they are equivalent to the size of one of the speakers times the square root of the number of speakers. In this case, that would be 12 times the square root of 2, (1.414) and that is 17". Now... for a given power into a speaker, to make it louder you either have to have a larger speaker (more surface area to radiate) or you have to move it farther in and out (sensitivity, bigger magnet, tighter gap, etc.)
Now we have the equivalent of a 17" speaker so it is much larger than the 12, but without the weight of a 17" because we are driving two 12's.
Next, speakers are very nonlinear because the suspension(surround, spider) is log, like your eardrum, a trampoline, the head on a drum, etc. So, if you split the power among many speakers, they are louder because they are making the most use of the power to move the cone before they start stressing the suspensing and going 'log'.
To demonstrate that, connect a Champ to a Marshall 4x12 and see what 5 watts will do.
That's also why the industry has always tested at 1 watt. We want to characterize all of the parameters of the speaker at a point where it is fairly linear.
So... the 2x12 you mention, despite their lower sensitivity would be louder than the higher sensitivity speaker, in my opinion.
Ted" Based on Ted's advice, two ten inch speakers would be the same as one 14.14 inch speaker." I agree, and good info, but am after a dB rating to represent the Cab's Total Volume. Knowing I have the volume equivalent of running a single 14.14" Custom Dr. Z speaker, when I run my 2x10 Cab... Doesn't really tell me how that would compare in volume, to running a single 12" Blue. If I knew exactly what dB a single Dr Z Custom 14.14" speaker would produce, I would be golden.
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Post by benttop (Steve) on Oct 12, 2010 12:02:21 GMT -7
Yeah, I agree. Ted never did give up that magic formula, so we are left to guess or perhaps measure. I'm sure that somewhere there is an article or treatice on the subject, but finding it has been difficult. Suffice it to say that two speakers are louder than one. How much louder is open to interpretation, especially since I am aware that for some folks, 3db is barely perceptible, yet for others, 1db is perceptible. If we are really that nonlinear ourselves, how can one characterize what "louder" really means?
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Post by Scott on Oct 12, 2010 13:42:15 GMT -7
So true my friend... Guess this will just go down in history as one of life's unsolved mysteries. I can say that when running a 2x10 Cab, along with a 1x12 Blue Cab, both will produce about the same amount of volume. My report on running a 2x10 Dr Z Cab, and 1x12 Celestion Blue together:ztalk.proboards.com/index.cgi?board=cabs&action=display&thread=34218It would be fun if we did know the exact dB a 2x10 Cab would produce at 1 watt/meter. I did update the post with... (Understand that the +3dB thing is an approximation, not exact science.)
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heycaptjack
Full Member
Be sure you ask the wife before you buy!!!
Posts: 108
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Post by heycaptjack on Oct 12, 2010 21:02:23 GMT -7
Lots of good stuff! Thanks for taking the time to help out and educate. Very helpful.
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Post by Scott on Oct 27, 2010 11:41:59 GMT -7
You're most welcome. Just added, and worth a look if your into tubes... TubeDepot's 'Journey to the Center of a Tube' video:
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Post by benttop (Steve) on Oct 27, 2010 16:12:48 GMT -7
Just added, and worth a look if your into tubes... TubeDepot's 'Journey to the Center of a Tube' video: That was pretty cool! I've never seen one disassembled that way.
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Post by Scott on Oct 28, 2010 20:54:43 GMT -7
That was pretty cool! I've never seen one disassembled that way. I thought so too... ;D Just added info about a possible alternate Power Tube, to use in your Jr.Question: Will a 7189 Power Tube work in a Jr?www.kcanostubes.com/search/node/7189I believe these are the rules on the 7189. The difference with pinouts between the 7189A and the 7189 are all the same except that the 7189A has:Pin 1 is connected internally to Pin 2 (grid) Pin 6 is connected internally to Pin 9 (screen)In the Jr's case, YES, a 7189 will work fine as a replacement for an EL84.A 7189A would usually work in an EL84 amp too, but a 7189 might not work in an amp designed for 7189A. There is one way a 7189A wouldn't work in an EL84 amp. If somebody was using pins 1 or 6 as a solder point for a resistor. Some amps will use pins 1 or 6 to get more point to point going. (Fender comes to mind) Will a 7189A work in a Jr? Unknown. The Tube Socket would have to be examined to verify that pins 1 and 6 are not in use. Also, you can't use an EL84 in place of a 7189, in an amp designed for 7189's. 7189's have 400V on the screen and plate, and the 7189A has even more at 440. The EL84/6BQ5 can only handle 300 volts, so they couldn't happily exist in an amp looking to send them an extra 100 volts or more. It's putting EL84's into an amp designed for 7189's that you may get into difficulty because of the higher voltages. A 7189 will run down to the same voltages as an EL84, but an EL84 won't run up to the same voltages possible as when using a 7189.
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Post by El Gato Blackie on Nov 8, 2010 14:19:39 GMT -7
What is the general life expectancy of the tubes that come stock with the Maz 18NR?
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Post by Scott on Nov 8, 2010 16:30:36 GMT -7
Just me talking, (If no defect's in the tubes) I'd say... On the NR...V1 and V2, years, if not the rest of your life... V3 - Myles stance concerning the Jr: EL84 tubes are very easy to drive. In the case of your MAZ Jr. the PI will last many output tube changes. I have seen no change in specs on PI's in MAZ, Mazerati, or other Dr. Z EL84 based amps over a dozen output tube changes, unless the PI had some sort of quality defect issue built into the tube originally.V4 & V5 - 1/2 a year to just over a year, depending on how much you play. (NOS EL84 Power tubes, not much longer.) V6 - Until it fails, or starts blowing fuses in your amp, could be over a year on the stock Rectifier. A NOS Rectifier will have a better feel, and may last you the rest of your life. If going to invest in any NOS tubes, I'd say go $95 GE Rectifier first...www.kcanostubes.com/content/nos-ge-5ar4-gz34Or some other high end NOS 5AR4 Rectifier. The Rectifier tube is the Jr's high voltage generator, and is responsible for the tightness and power of the amp. It can effect both the amp's tone, and feel... It however, is not located directly in the signal path.
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Post by El Gato Blackie on Nov 8, 2010 19:18:20 GMT -7
Thanks, I'm about to replace my power tubes and will now order a V3 too.
By the way, great thread!
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Post by benttop (Steve) on Nov 8, 2010 19:45:02 GMT -7
Myles has said many times that you can expect about 300 hours from a set of EL84's, but some pros change them after 30 hours. Good thing we're not pros eh?
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Post by Scott on Nov 13, 2010 20:11:53 GMT -7
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Post by benttop (Steve) on Nov 16, 2010 6:46:16 GMT -7
I noticed the same thing. There are a lot of dead links here as a result - I use them often as well.
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Post by Scott on Nov 28, 2010 4:54:10 GMT -7
Glad we found a way back to them all.
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zwish
New Member
Posts: 19
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Post by zwish on Jan 4, 2011 21:48:40 GMT -7
Bump for a very thorough and helpful post! Thanks to the OP. This should be kept on the front page.
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Post by Scott on Feb 1, 2011 2:53:04 GMT -7
TY!! Searching through the forum, to insure the best info is out on my favorite amp in the entire world... I found some outstanding posts from 2009, and hence, have now changed my official stance when asked, ' How much Power can a Jr. produce?' My new improved answer will be: The Maz 18 Jr. is one LOUD amp, and has been reported when running the stock Rectifier Tube to produce: 18W RMS at clip point, & 30W Peak.My Z dealer measured the one he got in for me on his scopey thingee, he reckons it 18watts at clipping and 32 at max output. So basically 18 watts of headroom. Sounds good to me. I had my Maz 18's output measured by an amp tech here in Auckland, New Zealand.
At my request he tested it with 3 different rectifiers. The results were as follows:
5AR4 rectifier = 18W RMS at clip point & 30W max,
5V4 rectifier = 15W RMS at clip point & 28W max,
5U4 rectifier = 12.5W RMS at clip point & 24.5 watts max.
So it really is 18 watts RMS with the stock 5AR4! He commented that the amp was very well designed to deliver the stated watts at the clip point (many don't)! This also begged for me to update my speaker info... One of the things I learned when running two Cabs at once, that I now keep in mind... So lets just say the Maz Jr. can produce 18 to 30 watts of power... That means for me, running with two Cabs in parallel: (A 2x10 and a 1x12) If needed, I can feed the Dr's 10's 4.5 watts, up to around 7.5 watts each. And my 15W Celestion Blue, would have to brunt 9 to 15 watts all by itself.
4.5 + 4.5 + 9 = 18 Watts 7.5 + 7.5 + 15 = 30 WattsGlad that the Jr's Power Output Testing data was posted! Thanks guys. OP updated...
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Post by Scott on Feb 22, 2011 14:51:25 GMT -7
FYI - OP Updated:
The text is correct on older MAZ JR.'s.
I did update the design some . 1/2 of V3 ( 12AT7) is the Reverb drive circuit & 1/2 of V3 is the wet/dry summer as before.
Now, I use V4 ( 12AX7 ) in a dual Triode parallel configuration as the Reverb recovery stage, instead of just 1/2 as before.
DR.Z
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Post by Scott on Feb 23, 2011 11:18:15 GMT -7
Two more updates to report: 1) smalltownsongs was kind enough to supply us with a Brake-Lite Demo on the legendary Maz Jr. Video has now been upgraded. 2) I called Mike at KCA NOS Tubes, and let him know that our link for his ' Cheapest NOS GE Rectifier recommendation' was out of stock, and wondered if he would be getting any more? Answer: Unknown if or when any new GE rectifiers would be in. Instead, he gave me a new rectifier recommendation for the Maz Jr. NOS JAN Philips/Sylvania 5AR4 (Mislabeled 5V4GA): www.kcanostubes.com/content/nos-jan-philipssylvania-5ar4-mislabeled-5v4ga-0OP Updated.
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Post by pickofthecrop on Jun 28, 2011 8:16:16 GMT -7
Thanks for all of this, what a wealth of info!
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Post by jlc on Sept 24, 2011 13:54:34 GMT -7
I'm a new guy on the forum, new to Dr Z. amps and really appreciate having this kind of information available.
It is very cool and helpful to have this kind of information to learn about the amp to go back and review when its tube time, speakers, cabinets etc. I can only echo other members and say thank you.
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Post by Scott on Nov 17, 2011 21:49:08 GMT -7
You guys are most welcome... ;D I just updated this thread with as much info I could find on the new Maz Jr. If you see anything that is not correct, feel free to call it out! Working to document everything about our favorite amp... Your Z-Brother Scott.
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Post by aufamily on Nov 18, 2011 10:16:26 GMT -7
This is as good as it gets! I know it doesn't feel like "work" when your as passionate about these amps as we all are...but its still effort and we appreciate it! Great reference info for a l ot of people.
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Post by Scott on Nov 18, 2011 15:51:01 GMT -7
Thanks aufamily...
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Post by ormond on Nov 27, 2011 13:21:34 GMT -7
Wow! What an amazingly thorough thread!!!!
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Post by Scott on Nov 30, 2011 22:34:29 GMT -7
Thanks Ormond...
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Post by lublin on Mar 28, 2012 11:36:14 GMT -7
Very cool thread. I've got the stock JJ's 12AX7's and rectifier tubes but through some NOS Saratov EL84's in the power section. WOW!
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Post by Scott on Mar 28, 2012 15:31:01 GMT -7
Thanks lublin...
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Post by rckline on Aug 28, 2012 13:49:54 GMT -7
Working out my new my MAZ 18 Reverb-BY FAR the best amp I've ever owned! What gorgeous cleans! An Ibanez tubescreamer fits perfectly for overdrive, but I'm liking the PaulC Tim better. Oh, and the EQ Bypass pedal? I don't even know what to say, having never heard such a glorious direct amp tone. Currently running into the MAZ 18R- P-90 Les Paul/Strats Tim (Boss PQ-4 in Tim's FX loop) MXR CC Red Witch Chorus Living in Oakland next to Koreatown, I've found bamboo serving trays make excellent pedalboards...(about $7.00) www.reverbnation.com/russellcarl
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