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Post by hosscartwheel14 on Mar 5, 2022 19:23:23 GMT -7
Hello everyone, I’m new in here.
I recently ( last summer ) purchased a Jetta
And I absolutely love it!! Now…. I noticed in older
Threads about the Jetta that the stock power tubes
are tung sol 7591 tubes but when I checked on the
Dr Z website for tube info it said that the
power tubes were JJ brand rather then tung-sol..
I’m curious because I want to purchase some spare tubes
and want to make sure I’m getting the right
ones….thanks in advance for your input.
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Post by Jaguarguy (Mike) on Mar 5, 2022 21:21:14 GMT -7
Welcome to the Forum! A lot of great people and information. It looks like initially the Tung Sol's were in the amp but as of Doc's latest listing on tubes he was recommending the JJs (as of 6/21). I know that a lot of people were having problems with the tung sols. Doc keeps pretty good tabs on who is producing good tubes and who's tubes are having issues. He probably switched to the JJs after they improved their quality last year. I'd go with the them. Unfortunately, tubes are a crap shoot these days! Maybe Doc or Frankie will chime in and let us know what the present recommendations for the Jetta are. I'd go with the JJs unless we hear something different from Z.
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Post by hosscartwheel14 on Mar 6, 2022 7:23:54 GMT -7
Thanks for the info my friend!!
I will order a set of matched JJs.
Brett.
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Post by helmi on Mar 6, 2022 8:10:23 GMT -7
Welcome to the forum.
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Post by RickJames on Mar 6, 2022 9:33:18 GMT -7
Got my beloved Jetta about a year ago, and was unsure about replacement power tubes. Ended up ordering a matched set of tung-Sol 7591A from StewMac.
Paws crossed
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Post by DRZ on Mar 6, 2022 11:47:59 GMT -7
OK its Sunday afternoon and time for a DR.Z post.
First let me say I have designed over 50 different Guitar amps, and the Jetta is certainly one of my favorites .
Its simple design , quote from Ken Fischer regarding amp design and building " The shortest distance reaps the greatest Tone ".
The amp is a collection of very High Quality components ( i.e. Triad OT, Celestion G 12 H , 7591A Output tubes, Metro Effects Loop , and high quality coupling caps. ) but in its simple construction it is a very efficient build. It has a huge sound for very compact size, and can be used in a variety of applications.
Its 30 watts of output power is usually way more then anyone would need in todays environment, and it's great PPIMV allows for low volume and great tone.
The design consists of 1 1/2 preamp tubes , and a pair of the almighty 7591A's.
The 7591A's were the last new output tube design released, it yielded output power of a 6L6 with size and demand of a 6V6.
So it makes big output with little input, the definition of Transconductance.
It had such great bandwidth that is was adopted by many Tube Amp Stereo Manufactures , as well as Ampeg and Supro guitar amps.
The premier 7591A was built by the American Tube company Tung Sol.
It was later copied and re-released by New Sensor .
The original Jetta design used the JJ 7591 it was a great sounding tube and I did favor it, but like most JJ Output tubes it had slight tube rattle.
Which led me to try the New Sensor Tung Sol reissue 7591.
Here is where the story gets interesting and pulls back the curtain on component selection and manufacturing.
The Reissue 7591 was not a big seller for NS, they had their initial supply of tubes from the first run and sold them sparingly to mostly Stereo owners.
I try some and liked them, no rattle, strong output , so I purchased what I found out later was all they had in stock.
When I went to reorder they were backordered , and I had to wait , which slowed Jetta production.
Realize that tube manufactures build tubes in extended runs, meaning they set up for a certain tube and run thousands of them , they inventory them and set up for another big run of another model tube.
So once I received the second run of Tung Sol 7591 A's they were not the same quality and I had a shelf full of rejected tubes that I could not send out in a new amp.
This lead me to the " Mac Giver fix of the chassis " .
I found that placing a finger on the rattling tube top stoped the rattle.
Damping rings were a little bit of a help but not the solution.
So I devised a way to put pressure on the tube top, isolate the socket from the chassis vibration, and slightly lower the self biasing and lower the value of the by-pass cap to decrease the strong low end response that did cause some of the rattle in the first place.
This turned out to be a great solution and allowed me use either NS or JJ 7591's.
I will try and film a video soon of how to do this simple upgrade.
If you are capable of changing the strings on your guitar you can install this mod.
There are a couple of parts needed and I will direct you to the sources of these parts in the video as well step by step installation .
Have a great Sunday.
Z
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Post by doctorice on Mar 6, 2022 12:00:36 GMT -7
At Z's recommendation, I installed a couple tube clamps in my Jetta. It solved the problem I was having with noisy Tung Sols. It's an easy fix.
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Post by adam on Mar 6, 2022 12:12:54 GMT -7
Can't wait for the video! Wondering if it can be adapted to other amps, but I'll wait and see.
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Post by RickJames on Mar 6, 2022 12:37:10 GMT -7
Thanks Doc, I do have that rattle.
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Post by hosscartwheel14 on Mar 6, 2022 15:47:26 GMT -7
I probably should add that I bought the head
version of the Jetta. I haven’t experienced any tube rattle
so far..I’ve only played it in my home since
my gigging through the pandemic has been
sparse..but I have some shows coming up in spring and summer and will check it out for any rattle.
Thanks for all the input and thank you Dr Z
for interacting with us!! Your as cool as a fan!!
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Post by gfreak on Mar 6, 2022 16:19:45 GMT -7
My combo has the Tung Sols, but nothing lasts forever! To be safe and ready to use either tube I did buy the parts for the mod.
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Post by RickJames on Mar 6, 2022 19:07:08 GMT -7
My combo has the Tung Sols, but nothing lasts forever! To be safe and ready to use either tube I did buy the parts for the mod. Do you have a link to the kit ? |
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Post by doctorice on Mar 7, 2022 9:22:19 GMT -7
My combo has the Tung Sols, but nothing lasts forever! To be safe and ready to use either tube I did buy the parts for the mod. Do you have a link to the kit ?
It may be easiest to go to the end and work back to find Z's post with the part numbers
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Post by nick0 on Mar 7, 2022 10:34:54 GMT -7
My Jetta combo has a little tube rattle that I can hear at home. I can't hear it when I'm playing with a band. Can't hear it in the room. Can hear it through the mic either. This never really bothered me.
The Jetta is such a great sounding and versatile amp! It impressed the heck outta me!
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Post by DRZ on Mar 7, 2022 11:13:10 GMT -7
My Jetta combo has a little tube rattle that I can hear at home. I can't hear it when I'm playing with a band. Can't hear it in the room. Can hear it through the mic either. This never really bothered me. The Jetta is such a great sounding and versatile amp! It impressed the heck outta me! Truer words have not been typed. Thank you Nick for sharing them. Me stating this fact would not have the same impact . The slight rattle of the 7591's would NEVER be heard on stage. It only effects bedroom players sitting in their underwear in their bedroom obsessing over a note or two that have a slight tail that is not caused by amp design. I have done my best to eliminate this issue on currant production amps, but I do not make the Vacuum Tubes in house . Everyone who works for me is a veteran long time experienced musician, and to the man can not relate to what some not all complain about in a combo amp. I share this feeling but mine goes a little further , players that buy used Jetta's and demand support without giving my company any real support. I think you know what I mean. A pissed off DR.Z |
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Post by nick0 on Mar 7, 2022 14:13:56 GMT -7
My Jetta combo has a little tube rattle that I can hear at home. I can't hear it when I'm playing with a band. Can't hear it in the room. Can hear it through the mic either. This never really bothered me. The Jetta is such a great sounding and versatile amp! It impressed the heck outta me! Truer words have not been typed. Thank you Nick for sharing them. Me stating this fact would not have the same impact . The slight rattle of the 7591's would NEVER be heard on stage. It only effects bedroom players sitting in their underwear in their bedroom obsessing over a note or two that have a slight tail that is not caused by amp design. I have done my best to eliminate this issue on currant production amps, but I do not make the Vacuum Tubes in house . Everyone who works for me is a veteran long time experienced musician, and to the man can not relate to what some not all complain about in a combo amp. I share this feeling but mine goes a little further , players that buy used Jetta's and demand support without giving my company any real support. I think you know what I mean. A pissed off DR.Z you're very welcome! I'm sure most guys know the deal. You have done a great job explaining this situation numerous times in the past. It is evident that there has been a lot of thought and effort on your end to silence any tube rattle due to the decreased tolerances of today's production tubes. Dr Z Amps are second to none in tone, durability, feel, quality, and the list goes on and on. The level of detail and articulation in the tone has made me a better player and has given me countless hours of joy and appreciation for my instrument. The fact that you're able to offer such a fantastic product at such a reasonable price, is a true testament to the hard work and dedication by all the folks there at Dr Z. Customer support and the available modification services offered are unheard of anywhere else (to my knowledge). Big shout out to Don! Your hard work and quality designs are appreciated by many players and listeners! Thank YOU! |
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Post by adam on Mar 7, 2022 17:24:20 GMT -7
Don't be mad, not your fault. We all appreciate your attention to detail with everything, and it's incredibly obvious in all the amps. They are all truly special works of sonic art made by master craftsmen and easily recognizable. There's a young guy on YT who's a fantastic player in the SRV realm who's always showing 50's/60's guitars and old Fender amps and he sounds fantastic (Mathew Scott). In one of the videos, he explained that every one of those amps has tube and cabinet rattle. Just saying. And maybe for anyone reading this, if tube rattle drives you bonkers, just buy a head and you won't have those problems. That applies to any tube amp manufacturer that you might consider. A quick search of "John Mayer live" and it's all heads and cabs, and sometimes he might substitute a 1x12 cab for a 2x12 or 2 2x12 cabs for the same amp. I'm sure there's exceptions to that, but those were pretty recent videos and might imply something along those lines. |
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Post by Chilly Gibbons (Todd T.) on Mar 7, 2022 18:16:32 GMT -7
Since I don’t have real playing space, studio, or anything like that I have “room rattle” in my basement. When it bothers me, I can usually isolate the problem but most of the time I just accept that it will happen at some frequencies. Either turn up and drown it out, or down and it stops. The culprit is usually a tool or part or something on a shelf.
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Post by adam on Mar 7, 2022 18:58:22 GMT -7
Since I don’t have real playing space, studio, or anything like that I have “room rattle” in my basement. When it bothers me, I can usually isolate the problem but most of the time I just accept that it will happen at some frequencies. Either turn up and drown it out, or down and it stops. The culprit is usually a tool or part or something on a shelf. I have that too. The furnace duct is sort of the worst reverb ever invented too. |
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Post by nicholas on Mar 9, 2022 4:52:33 GMT -7
My combo has the Tung Sols, but nothing lasts forever! To be safe and ready to use either tube I did buy the parts for the mod. Do you have a link to the kit ?  |
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Post by RickJames on Mar 9, 2022 8:35:20 GMT -7
Thanks much!
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Post by gfreak on Mar 9, 2022 9:47:45 GMT -7
RickJames Sorry I missed your post. By the time I saw it everyone else came through. |
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Post by RickJames on Mar 9, 2022 10:45:39 GMT -7
No problem, folks have been very helpful here, as well as Doc of course!! Thanks again
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Post by DRZ on Mar 9, 2022 10:51:31 GMT -7
I have booked next Wednesday to film the AMA on " solution to new tube rattle dilemma ".
Hopefully I can record and release this video next Wednesday.
Z
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Post by nick0 on Mar 9, 2022 13:33:55 GMT -7
I have booked next Wednesday to film the AMA on " solution to new tube rattle dilemma ". Hopefully I can record and release this video next Wednesday. Z I'm excited for another AMA!! It's been way too long! |
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Post by hosscartwheel14 on Mar 9, 2022 22:35:49 GMT -7
I just want to add, the Dr Z Jetta (head version)
is the best sounding amp I’ve ever owned!!
I’ve been playing guitar both semi and full
professional since I was around 15 years old ( I’m 55 now )
I’ve played through mostly tube amps all through
my years of performing..none of them sounded
as good as the Jetta that I own now. I bought it new
from Sweetwater last June. I’m hoping that someday
I can get another Dr Z amp..maybe a Z Wreck
or a maz sr..
Anyway..I’m looking forward to playing some
shows this spring and summer and cranking that Jetta
up!!!! Im saving up my nickels for a Zcab …,
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Post by nick0 on Mar 10, 2022 3:44:24 GMT -7
I just want to add, the Dr Z Jetta (head version) is the best sounding amp I’ve ever owned!! I’ve been playing guitar both semi and full professional since I was around 15 years old ( I’m 55 now ) I’ve played through mostly tube amps all through my years of performing..none of them sounded as good as the Jetta that I own now. I bought it new from Sweetwater last June. I’m hoping that someday I can get another Dr Z amp..maybe a Z Wreck or a maz sr.. Anyway..I’m looking forward to playing some shows this spring and summer and cranking that Jetta up!!!! Im saving up my nickels for a Zcab …, The Jetta is a really impressive design. Every time I get it fired up, I'm happy with the sound. It seems to take any guitar and any combination of pedals so well. It reproduces what you put into the front with a boat load of power and detail! |
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Post by GT Roger on Mar 11, 2022 6:21:50 GMT -7
I've only heard tube rattle once from my Jetta combo and it was when I was practicing at home.
I use mine for my original band and at church (along with other amps in stereo). I've never heard the rattle playing with a band.
We live stream at church and I've listened back to the stream with head phones and have never heard the rattle.
Looking forward to the AMA. I love the Jetta!
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Post by hosscartwheel14 on Mar 20, 2022 21:43:17 GMT -7
I’m a bit concerned….
I can’t find any seller with power tubes for
my Jetta. They are out of stock on all brands.
Other than some thieves trying to get 200
bux for a set of used ones..anyone know if
7591s will be restocked from manufacturers?
I don’t have any spares….
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Post by perryr on Mar 20, 2022 22:04:11 GMT -7
Surge in demand wiped out inventories (panic buying). Hard to say where pricing will normalize to. Looks like vivatubes.com has 7591’s available.
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