John Mayer/Wonderland 100 watt build

Overdrive Special, Steel String Singer, Dumbleland, Odyssey, Winterland, etc. -
Members Only

Moderators: pompeiisneaks, Colossal

Post Reply
User avatar
Guy77
Posts: 906
Joined: Sat May 31, 2014 2:46 am
Location: Toronto, Canada

John Mayer/Wonderland 100 watt build

Post by Guy77 »

I finished building a 100 watt John Mayer/Wonderland build last night and fired it up for the first time. I used hammond twin reverb transformers.
I set the voltage divider from the stock 68K-1M to 150K - 1M that many people here recommend. Amp sounded good. I no longer have the 50 watt one I built since I had sold it to a friend .

I noticed something different in the sound right away! Something was missing in the sound, it was like there was an openness that was no longer present, the amp was not breaking up a little like the 50 watt what one did. I should mention that I only play in the basement of my house.
I decided to pull 2 tubes and adjust the impedance switch to 4 ohms since it was a 100 watt OT going to 8ohm G1265 speaker. Suddenly the sound I craved was back!!! I realized what I like so much about these amps is how it can start to break up a bit when you engage the boost switch ( lift the ground wire from the Mid pot and the Bass pot) and dial up the volume and lower the master a bit. I know this is not a Marshall amp but I like the bit of grind you can get from these amps when dialed in accordingly. I did one more thing different with this amp and that was install separate bias pots for each power tube. I used the information here to wire up the 2 pots and it worked great.

https://robrobinette.com/Generic_Tube_A ... anced_Bias

I was then able to run the amp with 1 6L6 tube and one EL34 tube, I was surprised how good this sounded! Here is a pic of the chassis from outside. Its an ODS chassis that I drilled 2 more holes into for the 5 preamps tubes in total. Waiting on faceplates to arrive.

Cheers!

Guy
You do not have the required permissions to view the files attached to this post.
j0k3335
Posts: 138
Joined: Sun Sep 23, 2007 5:09 pm
Location: Paris, FRANCE

Re: John Mayer/Wonderland 100 watt build

Post by j0k3335 »

I'm fighting with a Bluesmaster who does not sound to my taste (and looking for some help here ... but the forum gets very quiet ...?) SO I'm far from John Mayer / Wonderland!

BUT congratulations for your building !

And especially thank you for your link that does not contain ONLY these indications for bias but a huge lot of information!

By cons, you say that in your push-pull assembly (normal I guess?) You mount on one side a 6L6 and in the other side a EL34 ??? I had never seen that?
(Boogie gets in his simulclass a game of 6l6 and a game of El34 each push-pull but that's all I know, or in single ended building, some different tubes "in parallel" )

Anyway, congratulations again : I will be real proud and happy to be able to build a whole amp like you have done :wink:
User avatar
martin manning
Posts: 13080
Joined: Sun Jul 06, 2008 12:43 am
Location: 39°06' N 84°30' W

Re: John Mayer/Wonderland 100 watt build

Post by martin manning »

Guy77 wrote: Fri Dec 01, 2017 11:54 pmIts an ODS chassis that I drilled 2 more holes into for the 5 preamps tubes in total.
Very nice, and I like this solution for adding two more preamp tubes!
User avatar
norburybrook
Posts: 3290
Joined: Mon Jan 06, 2014 12:47 am
Location: London
Contact:

Re: John Mayer/Wonderland 100 watt build

Post by norburybrook »

Guy77 wrote: Fri Dec 01, 2017 11:54 pm I finished building a 100 watt John Mayer/Wonderland build last night and fired it up for the first time. I used hammond twin reverb transformers.
I set the voltage divider from the stock 68K-1M to 150K - 1M that many people here recommend. Amp sounded good. I no longer have the 50 watt one I built since I had sold it to a friend .

I noticed something different in the sound right away! Something was missing in the sound, it was like there was an openness that was no longer present, the amp was not breaking up a little like the 50 watt what one did. I should mention that I only play in the basement of my house.
I decided to pull 2 tubes and adjust the impedance switch to 4 ohms since it was a 100 watt OT going to 8ohm G1265 speaker. Suddenly the sound I craved was back!!! I realized what I like so much about these amps is how it can start to break up a bit when you engage the boost switch ( lift the ground wire from the Mid pot and the Bass pot) and dial up the volume and lower the master a bit. I know this is not a Marshall amp but I like the bit of grind you can get from these amps when dialed in accordingly. I did one more thing different with this amp and that was install separate bias pots for each power tube. I used the information here to wire up the 2 pots and it worked great.

https://robrobinette.com/Generic_Tube_A ... anced_Bias

I was then able to run the amp with 1 6L6 tube and one EL34 tube, I was surprised how good this sounded! Here is a pic of the chassis from outside. Its an ODS chassis that I drilled 2 more holes into for the 5 preamps tubes in total. Waiting on faceplates to arrive.

Cheers!

Guy
Guy,

Interesting comments. I personally like the fact it DOESNT break up :D I have plenty of amps that beak up so for me this amp is a beautiful clean amp and takes pedals really well, which is how John Mayer used it.

I love your different output valves and separate bias, really cool idea, so thanks for sharing that :D I've now got something else to experiment with on a future build.

It just goes to show we all like our amps to sound different :D

Marcus
User avatar
Guy77
Posts: 906
Joined: Sat May 31, 2014 2:46 am
Location: Toronto, Canada

Re: John Mayer/Wonderland 100 watt build

Post by Guy77 »

Thanks for all the comments guys. Hi j0k3335, yes that url i gave regarding installing the separate bias pots actually has so much amazing information about building amps! You could spend days and days learning amazing things. I believe Rob who created the site is also a member here on ampgarge!

Hi Martin yes it was quick and easy to drill the extra 2 holes and bingo an ODS chassis is a JM chassis! I also used the JTM 45 turrent boards from tubesandmore.com . They are so affordable!

Hi Marcus. Yes having 2 bias pots is great! I can dial in the tubes to be exactly the same bias even if they are slightly off when first purchased. I ended up going back to 2 x 6L6 tubes on this amp , I found that overall the amp sounded best with 6L6. I am also using the amp without the boost switch , I am finding that the TMB controls are actually very responsive on this amp! Since now I have extra space I will install a GZ34 rectifier and place that on a switch to toggle between tube or solid state rectifier. Rob's site has a nice diagram on doing that. BTW congratulations on your gig with #102 build at the Mark Knopflers studio!




Cheers!

Guy
You do not have the required permissions to view the files attached to this post.
Last edited by Guy77 on Fri Dec 29, 2017 1:05 am, edited 1 time in total.
User avatar
norburybrook
Posts: 3290
Joined: Mon Jan 06, 2014 12:47 am
Location: London
Contact:

Re: John Mayer/Wonderland 100 watt build

Post by norburybrook »

Cant beat a pair/quad of 6L6's IMHO :D


I do wonder though if the fact that the valves aren't perfectly matched is actually the reason they sound 'great'. If you could perfectly match them would you loose something?

I do not know the answer to this practically or theoretically, I'm just asking the question.

Rob's site is awesome. It's the kind of info I needed when I was first starting out. Things explained well and with great pictures etc.


we have some great people here on this forum.

Steve Luckley has a great site too and is a member here.

well done on your build Guy.

Marcus
User avatar
martin manning
Posts: 13080
Joined: Sun Jul 06, 2008 12:43 am
Location: 39°06' N 84°30' W

Re: John Mayer/Wonderland 100 watt build

Post by martin manning »

norburybrook wrote: Sun Dec 03, 2017 5:50 pmI do wonder though if the fact that the valves aren't perfectly matched is actually the reason they sound 'great'. If you could perfectly match them would you loose something?
Matched idle current is only part of the story. Remember the PI trimmer? It is compensation for miss-matched transconductance, and generally for this type of amp a balanced power section sounds better.
User avatar
norburybrook
Posts: 3290
Joined: Mon Jan 06, 2014 12:47 am
Location: London
Contact:

Re: John Mayer/Wonderland 100 watt build

Post by norburybrook »

martin manning wrote: Sun Dec 03, 2017 7:10 pm
norburybrook wrote: Sun Dec 03, 2017 5:50 pmI do wonder though if the fact that the valves aren't perfectly matched is actually the reason they sound 'great'. If you could perfectly match them would you loose something?
Matched idle current is only part of the story. Remember the PI trimmer? It is compensation for miss-matched transconductance, and generally for this type of amp a balanced power section sounds better.
Thanks Martin, as my Guru on all things amp related I will add this to my ever growing knowledge data base.



Marcus
User avatar
Guy77
Posts: 906
Joined: Sat May 31, 2014 2:46 am
Location: Toronto, Canada

Re: John Mayer/Wonderland 100 watt build

Post by Guy77 »

Me and a friend had some fun with my JM 100 amp last weekend. He played some heavy rock tones through the amp with a les paul. We had the amp preamp cranked to 10 and the master cranked to 10. We then placed a Air brake attenuattor just at the start of bedroom setting right after the 5 th position setting.
We ran the amp through 2X12 celestion golds.
Here is what we got!! I am still learning how to use my zoom h5 mic so excuse the clipping !
Caution if you have earbuds volume is high at start.




Cheers

Happy New Year !

Guy
You do not have the required permissions to view the files attached to this post.
Post Reply