[Guidostrunk]

Can you post a "before" pic?

Here's a stock pic of MJ2.

 

[Guidostrunk]

Those are Brimar CV4033 tubes on adapters in the pic lol.

 

[Guidostrunk]

For me this mod on the MJ2 has been the most significant change out of any amp I've had done. The LP was great. Especially with the Alps pot installed, but that was pretty time consuming with all the faceplate modifications and it falls short of the MJ2.
The added benefit is using 12at7 tubes on adapters. I love the 12au7 but the 12at7 for me is where it's at.

 

[M-83]

That was a sweet emd-game headphone rig system. I hope you eventually get another system soon

Thanks. Yeah hope so too. One day I'll get there.

 

[M-83]

This is essentially a super version of the Monoprice LP mod from 2020. It takes the stock MJ2 and puts it up to 11!

The modification involves swapping out the stock power and input/output capacitors with Nichicon Muse/Finegolds or Elna Silmic IIs for increased dynamics and staging. The row of large caps on the left in the image includes 8 35v, (4 standing and 4 laying down) and two 250v caps (two at the front). This thing has a lot of power and the new capacitors help to more quickly discharge that power and increase the liveliness of the MJ2. The collective effect of the cap mod is to increase the overall dynamics and detail while also taming some of the brightness. The MJ2 chassis is fairly tightly packed, so it takes some work to get everything in their, but def. worth the efforts. I have been working with Sam for at least a month now on his and mine, and now am working on Jonathan's and I am impressed with it each time over stock.

Disclaimer:
If anyone is looking to do this mod themselves, make sure to discharge the caps before taking any of them off of the board. While doing Jonathan's, after traveling for a week direct from Schiit, the board was still holding 150volts in capacitance...easily able to do some damage to the board. I use a lightbulb to discharge, and check with a volt meter until I am down to 1 v or less.

Very impressive. If you don't mind me asking....how much are the parts and how many man-hours does the mod take?

 

[G0rt]

For me this mod on the MJ2 has been the most significant change out of any amp I've had done. The LP was great. Especially with the Alps pot installed, but that was pretty time consuming with all the faceplate modifications and it falls short of the MJ2.
The added benefit is using 12at7 tubes on adapters. I love the 12au7 but the 12at7 for me is where it's at.

I occasionally try various valves in my MJ2, but always return to CV4033's.

I understand there's coupling capacitance between the tube Vas and CrossFET stages. One might expect those to be critical components as well.

 

[ksorota]

Very impressive. If you don't mind me asking....how much are the parts and how many man-hours does the mod take?

Approximately $150 in parts and about three hours to do the work.

 

[Guidostrunk]

I occasionally try various valves in my MJ2, but always return to CV4033's.

I understand there's coupling capacitance between the tube Vas and CrossFET stages. One might expect those to be critical components as well.

It's funny you say that because I do the same with the cv4033. The CBS Hytron 7728 was the end all be all when I got them. Even after extensive A/B listening sessions. I spent a solid week with the 7728 and swapped back in the cv4033. There's just something about that tube that no other tube ,with the exception of the A2900 , does.

It's the most transparent, holographic, realistic imaging tube next to the A2900 with a midrange and bass response that grabs you by the plums . I can't stress enough that the Brimar CV4033 is not a Mullard Blackburn sounding tube. They are two very different tubes. I think a lot of people miss out on the cv4033 due to " It's produced in England so it must be syrupy and dull". Not the case at all.

 

[Guidostrunk]

Don't forget to give them CV4033 another go @ksorota lol.

 

[G0rt]

It's funny you say that because I do the same with the cv4033. The CBS Hytron 7728 was the end all be all when I got them. Even after extensive A/B listening sessions. I spent a solid week with the 7728 and swapped back in the cv4033. There's just something about that tube that no other tube ,with the exception of the A2900 , does.

It's the most transparent, holographic, realistic imaging tube next to the A2900 with a midrange and bass response that grabs you by the plums . I can't stress enough that the Brimar CV4033 is not a Mullard Blackburn sounding tube. They are two very different tubes. I think a lot of people miss out on the cv4033 due to " It's produced in England so it must be syrupy and dull". Not the case at all.

Brimar did really good work, and literally wrote the book on tube reliability, so these Mil Spec bottles should serve for a good long time.

They also sound superb in Vali2, Lyr3 and Valhalla2.

 

[Rowethren]

I don't suppose you could provide some details on the CV4033? Like which verity/age to look for and if they need an adaptor? They sound like an interesting tube.

 

[G0rt]

I don't suppose you could provide some details on the CV4033? Like which verity/age to look for and if they need an adaptor? They sound like an interesting tube.

Mine came from TubeMonger, and need adaptors, which TubeMonger can also provide. The tubes themselves were originally wire lead, but TubeMonger adds pin bases.

The CV4033's I have are from 1962, but availability is catch as catch can.

 

[Guidostrunk]

Mine came from TubeMonger, and need adaptors, which TubeMonger can also provide. The tubes themselves were originally wire lead, but TubeMonger adds pin bases.

The CV4033's I have are from 1962, but availability is catch as catch can.

Mine are from the same year. I also have their adapters. They should be getting more stock in soon.

 

[Guidostrunk]

I don't suppose you could provide some details on the CV4033? Like which verity/age to look for and if they need an adaptor? They sound like an interesting tube.

Here's a link to the tubes. Currently sold out.
https://www.tubemonger.com/Brimar_CV4033_NOS_1960_62_Prem_CV4024_STC_Eng_FAC_p/2042m.htm

And the adapters needed. Currently sold out as well.
https://www.tubemonger.com/12Axx_to...IB_1960s_p/12axx-ecc88-adap-novib-mcmurdo.htm

 

[Rowethren]

Great thanks for the replies both! I will send TubeMonger an email and ask about them. I bought my 6922 socket savers from them a few years ago and they have been great.