Blackheart Little Giant and the Mercury Mag Mod

[BJosephs]

Hey everybody, this is my first post here. I have seen a lot of talk about the BHLG and the $325 Mercury Magnetics Mod Kit. Not wanting to spend that much for a PT that I don't think i'll need, a choke I can get from hammond, and some small components i'd rather select myself, I contacted MM to see if the OT could be purchased separately.

The answer was no, but they recommended a stock OT called the SE-9K-M.

It has a 9K primary which I thought was a little high (that's why I'm posting) and it is "Medium" sized - they claim the over sized OT is better. According to them there are many BHLG users that have installed the OT with good results.

Price is $160.00

Whta do you guys think? 9K primary? Oversized transformers? Mercury replacements in general?

[HTH]

I've just installed a Mercury Magnetics OT in an AC30, it's like a whole new amp now - MASSIVE improvement.

I know that MM are fond of overspec'd OTs and PTs for those Epi VJ type amps. I've got one of those amps myself and have the kit here ready to install.

Will let you know what it's like once I get customer amps out the door.

[BJosephs]

Great! Thanks, HTH. So maybe I would entertain the thought of an oversized MM OT. Any thoughts on the impedance?

[BJosephs]

I decided to buy a MM OT after all but I selected their generic 5k Single Ended unit. It is enormous and very cool looking - it took two new holes and a shoe horn to fit it on to the chassis. I am satisfied with the sonic quality as well, the low end is profoundly better with this unit. The amp feels a louder, but this may be my imagination.

I have not decided wether or not the price is appropriate for the quality given how well a Hammond performed in my Valve jr., but I figure that if, and when, I buy a second Blackheart I will probably put the same OT in it as well.

[Chris - CMW amps]

That MM 9k se-OT is great for 6V6s or EL84s imho, with mismatching you can also use bigger tubes.

[Chuck_Farlee]

9K for the primary seems a little high to me. Part of the problem with the Valve Junior amps was that they used a 7.5k OT which sounded terrible. An EL84 in SE Class A wants to see about 5K. The new version 3 VJs have a 5.2k primary OT and they sound much better than the previous versions with the 7.5k OTs.

By all accounts MM iron sounds fantastic, but their marketing ploys leave a lot to be desired. As you have deduced, paying $325 for an upgrade kit is not a good investment. Especially going into a $150 amp. They pulled the same BS with the VJ kit: they are a transformer company and want to sell you transformers. Consequently they provided two unneeded transformers for the VJ (and now the BH amp as well).

If you bought just an OT replacement, you did good. The VJ ahd BH upgrade kits are a waste of money.

chuck

Hey everybody, this is my first post here. I have seen a lot of talk about the BHLG and the $325 Mercury Magnetics Mod Kit. Not wanting to spend that much for a PT that I don't think i'll need, a choke I can get from hammond, and some small components i'd rather select myself, I contacted MM to see if the OT could be purchased separately.

The answer was no, but they recommended a stock OT called the SE-9K-M.

It has a 9K primary which I thought was a little high (that's why I'm posting) and it is "Medium" sized - they claim the over sized OT is better. According to them there are many BHLG users that have installed the OT with good results.

Price is $160.00

Whta do you guys think? 9K primary? Oversized transformers? Mercury replacements in general?

[HTH]

I wouldn't say the VJ kit is a waste of money - both the PT and OT are over-rated to such a point where you can run anything upto a KT88 in that amp providing you add an octal socket.

One of the Mercury-approved mods is to run the existing EL84 in parallell with a 6V6 - you can't do that with the existing PT.

That said though, if all you want to do is run EL84s and are looking for a sweeter OT, the Mercury Vox AC4 OT would be just the ticket (it's next on my list).

[Chuck_Farlee]

I wouldn't say the VJ kit is a waste of money - both the PT and OT are over-rated to such a point where you can run anything upto a KT88 in that amp providing you add an octal socket.

I disagree.

One of the Mercury-approved mods is to run the existing EL84 in parallell with a 6V6 - you can't do that with the existing PT.

Sure you can, several people on the Sewatt.com BBS have reported doing just that. It is a popular and well discussed mod. And all with the stock PT.

A couple guys have even run a KT88 tube in their VJs using the stock PT and a Hammond 125ESE. It isn't optimal, but it works and doesn't overheat the PT.

That said though, if all you want to do is run EL84s and are looking for a sweeter OT, the Mercury Vox AC4 OT would be just the ticket (it's next on my list).

Thanks for the tip. Just out of curiosity, how much is the MM Vox AC4 OT?

chuck

[HTH]

What do you disagree with Chuck? (that it's not a waste of money?)

As for the MM AC4 OT, you're looking at $100 for the single speaker tap version or $125 for the version with 4,8 and 16 ohm taps.

The stock Epi VJ PTs musy be fairly over-rated to run KT88s - does the heater voltage drop? I'd be skeptical about running a KT88 in a stock VJ for any length of time without the PT failing, but you never know (time will tell).

[Chuck_Farlee]

What do you disagree with Chuck? (that it's not a waste of money?)

I believe the MM mods for both the VJ and the BH amps are a waste of money, sorry that I was unclear. Look at it this way: you are paying for two unnecessary transformers, the choke and the PT. The telling factor is that MM will not sell the OT separately from the set. Anybody who has spent time reading up on the VJ (or BH) would buy only the OT and would not buy the whole set.

As for the MM AC4 OT, you're looking at $100 for the single speaker tap version or $125 for the version with 4,8 and 16 ohm taps.

That is a lot of coin for an OT to put in a $130-$150 amp.

In one VJ rebuild I did, I used the Heboer SE OT that Dobermanamps.com sells and it was about $65 shipped. It has 2.5k, 4k, and 6k ohm primaries, 4, 8, 16 ohm secondaries. It is rated for 160mA through the core. Overkill, I'll admit, but it sounds much better than a Hammond 125ESE. But it is almost double the cost.

I'm wondering if the MM AC4 OT sounds 3X better as it costs 3X as much as the equivalent Hammond OT.

The stock Epi VJ PTs musy be fairly over-rated to run KT88s - does the heater voltage drop? I'd be skeptical about running a KT88 in a stock VJ for any length of time without the PT failing, but you never know (time will tell).

That is my point: the VJ PT is over-rated for the stock VJ circuit. I believe Epiphone used that PT in another amp that required more current capacity. Having said that, I personally wouldn't run a KT88 in a VJ.


chuck

[HTH]

It makes sense that Epiphone would use the same PT as a similar amp if they can get away with it - cheaper 'per unit' price.

All I will say is that all the Mercury Magnetics transformers I've tried have totally blew away the stock transformers. I suppose it all depends on how fussy you are as to whether it's worth paying MM's prices.

[Rick Erickson]

I've just installed a Mercury Magnetics OT in an AC30, it's like a whole new amp now - MASSIVE improvement.

HTH - I'm curious, which (AC30) OT did you get? They have at least seven versions available: (1) Albion, (2) Woden , (1) Haddon, (3)R.S. I' replacing one in a Rose-Morris era AC-30, probably going to go with the standard Woden OT. I have an original Woden in my Grey top JMI AC30 and that amp sounds great to me.

RE

[HTH]

I've just installed a Mercury Magnetics OT in an AC30, it's like a whole new amp now - MASSIVE improvement.

HTH - I'm curious, which (AC30) OT did you get? They have at least seven versions available: (1) Albion, (2) Woden , (1) Haddon, (3)R.S. I' replacing one in a Rose-Morris era AC-30, probably going to go with the standard Woden OT. I have an original Woden in my Grey top JMI AC30 and that amp sounds great to me.

RE

Rick,

I used the RS one which is the same OT used in the original Bluesbreakers. Apparently the very early AC30s used them too.

Mercury told me that it breaks down like this...

* Woden is the most Beatlesy tone
* Haddon and Albion are leaning slightly more to a bit of Marshall
* Radiospares O45RS-L was used in the earliest AC30’s and is very thick and rich with true Vox tone

The cool thing about the RS one is that you have primaries for 6k6, 8k, 9k and UL taps - very versatile.

[Guitarist]

I guess there is a consideration as to what tube you'd like to use for output. Whay pay for a KT88 capable OT when you just want to use el84s or 6v6. But, you want BIG sound just not major watts. So what do you buy?
Hebbour, theyre expensive looking around Mojo's site Doby didn't list them. I called New Sensor and they have a Bassman replacement made in the USA that is around $60. Maybe that work for a VJunior, I don't know. I really would like to know which item to get when upgrading or replacing an OT as you want to reach that sweet spot of value and tone.
It's is pretty rare to read about a shootout. eg Ampeg stock transformer vs MM or MM vs. Partridge.
I've paid less for a car than these transformers' prices