Succesful Mercury Output Transformer install....

Discussion - HT-5 amplifiers.
BobZ
Posts: 22
Joined: Mon Oct 18, 2010 12:00 am
Location: New Jersey

Sat Jul 07, 2012 5:28 pm

Here is the quick summary of the install of a Mercury Magnetics output transformer in a HT-5.

All standard safety precautions are recommended... drain the caps before working on it.... don't do it in the bath tub etc.

What you will need:
Electric drill with small diameter bit for a pilot hole.
1 3/8 inch sheet metal screw
wire strippers
soldering iron, solder etc.

AMP Female Disconnects 16-14 .250 (10pak for a couple dollars)
Standard wire connectors (to float the 4 ohm tap lead)
electrical tape


The Mercury transformer comes with a single sheet depicting the primary and secondary winding.

Locate the existing output transformer ... make a diagram of where the wires go before you start doing anything...

Imnportant: The colors of the wires do not match up between the transformers... Example: The Mercury primary winding center TAP is RED... The RED lead off the EXISTING transformer goes to pin 6 on the tube... So its not a case of just taking out the one transformer and popping in the other as the wires do different things....

Once you have drawn your diagram of where the existing wires on the stock transformer go... then its time to remove it from the amp...All but 2 of the connections are done with the AMP connectors and just pull off... The connections to the tube are soldered on...and need to be desoldered ... the wires are close so be careful not to burn other wires....

Once the stock transformter is out... Mount the Mercury on the top right where the old one was... You can use one of the mounting holes and the screw... As the Mercury is a lot bigger... a new hole needs to be drilled though the sheet metal for the second connection...

Align the new xformer and drill a hole using the plate of the Mercury as the guide... just enough to pressure to get through the metal.. be careful so as not to hit the circuit board if the drill bit punches through...

Once the drill punches through ... take your new sheet metal screw and screw down the transformer... a 3/8" screw leaves plenty of clearance below so as not to hit the circuit board underneath... You may need to drill a few times... I started with a VERY small drill bit and the screw would not cut through... so I kept increasing the size of the bit until the hole was just big enough for the screw to get through it ... Once you get the right size hole its a nice tight connection....


Route the wires through the 2 holes in the sheet metal.... The 3 wire side is the Primary of the Mercury Transformer and the 4 wire side is the secondary....

IMPORTANT: The Red wire on the primary is what Mercury uses as the center TAP.... This wire needs a AMP connector on it and then connects to SP6.

The Blue wire goes to Pin 1 on the tube socket... This can be soldered as mine is now or next time I go to Home Depot I will get some real small AMP connectors and make it a pull on/off connection...

The Brown off the Mercury primary goes to Pin 6 on the tube socket.... same issues as above regarding getting a new amp connector for it..

So that takes care of the Primary side.... Red with an AMP connector to SP6, Blue to Pin 1 of the tube, and Brown to Pin 6 of the tube...


For the secondary ... The Black wire is COM, needs an AMP connector and goes to SP1.

The Orange is for a 4 ohm tap that the HT-5 doesn't have... You can just cap it off .. wrap electrical tape around it and then use one of those screw on electrical caps... then just bury the wire somewhere....

The Green wire is the 8 ohm jack... so crimp on an AMP connector and connect to SP3 which is just behind the 8 ohm jack ....

The Yellow wire is the 16 ohm jack ... crimp on an AMP connector and connect to SP2 which is just behind the 16 ohm jack...

Your DONE!

It took me longer than it should have because I was having conversations with Mercury about their wiring....

If I was going to do one right now I could do it in under 30 minutes...

The confusing part was figuring out the wiring as different manufacturers use different colors....

Just remember that the RED wire on the Mercury is the center tap and MUST go to SP6... Once you get that .. its easy to see where the others go....

Result? Really Really Good! The tone to me is the same... it just has more of it.... a DEPTH... almost like you hear the tone down to a deeper layer... I'm really happy with it....

They said it takes 30 hours before it opens up and gets to the sweet spot....

Any questions on the install post here and I'll be glad to answer them....










motocooney2@gmail.com
Posts: 1
Joined: Fri Jul 20, 2012 12:00 am

Fri Jul 20, 2012 3:23 am

One question...what's the part # for the Mercury Magnetics Transformer?
Where'd you buy it and how much?
Thanks

BobZ
Posts: 22
Joined: Mon Oct 18, 2010 12:00 am
Location: New Jersey

Sat Jul 21, 2012 8:22 pm

The Mercury Magnetics transformer for the BlackStar HT-5 is.... BLKSTR-HT5-O it was 195.00....

I got it directly from Mercury Magnetics. If you use an amp tech and have them do the work they can save you money on the
transformer because they get a deal because of the number they buy from Mercury, but then you have to pay the amp tech to
do the work.... In my case I figured I'd give it a shot and it ended up working out well....


I dealt with Patrick... just ordered it over the phone... Patrick@MercuryMagnetics.com

http://www.mercurymagnetics.com/pages/mainframe.htm

They also have a choke listed for 40.00... its only 2 wires and gets installed in place of R10 on the circuit board....

I asked him about their "multi choke" (adjustable choke) and he said that it would work great...

This is the part number for the multi choke... MM-MULTI-12H Its 65.00.... the non adjustable choke is 40.00...

For me I would spend the extra 25 bucks and have the ability to play with the adjustments....


Mercury's exclusive multi-tap Multi-Choke -- Size: Large
2 Henry (DCR = 32Ω)
5 Henry (DCR = 50Ω)
7 Henry (DCR = 58Ω)
10 Henry (DCR = 69Ω)
12 Henry (DCR = 76Ω)


65.00

Off the Mercury website...


Attention guitar amp designers... techs... players... tone tweakers!

MultiChoke
Introducing the first variable choke!

Mercury's NEW MultiChoke offers you these important benefits:

The first tunable chokes to help you fine-tune your amps!

Quickly helps you find your amp circuit's sweet-spot!

Versatility without having to do serious amp mods!

A BIG TONE bang for not a lot of bucks!

Think of a choke as a shock-absorber for your amp's power transformer. Did you know that upgrading your tired old
or wimpy reissue stock choke -- or adding a Mercury choke to an amplifier that doesn't have one* -- will actually extend
the life of your power transformer and rectifier?

*Amp manufacturers often cut costs by the use of a resistor in place of a choke. This choice has absolutely nothing to
do with tone, it's purely economic. Replacing that resistor with a choke is a low-cost upgrade that'll usually give you a
huge improvement in tone.

Your amp's tone noticeably improves with any peaked and tweaked, hand-tuned choke from Mercury.
Mercury users tell us that they hear a tonal richness that was not there before adding one of our chokes.
Why? Because a choke provides musical smoothing to your amp's circuit. It also has a huge impact on touch-sensitivity
and tone dynamics.

A choke is so much more than a simple inductor. It can also store energy like a capacitor. Better voltage regulation
results from using premium-quality chokes. The choke puts less stress on your power transformer and permits higher
load currents to be drawn from vacuum tube rectifiers without exceeding their peak current rating. This means life
extension for your tube rectifier -- and even solid-state rectifiers run happier!

Mercury's NEW MultiChoke is in a league by itself. The MultiChoke allows you to quickly and easily audition several
different choke values to determine the best possible fine-tube the tone from your amp. And, the MultiChoke saves
time and money by eliminating the need to purchase a stack of single-value chokes -- not to mention all of the added
time needed to solder/de-solder leads for your tests.

Depending upon your needs, Mercury offers several MultiChokes with varying value sets. Currently available sets include:

1, 2, 3, 4 & 5 Henrys

1, 3, 5, 7 & 9 Henrys

2, 5, 7, 10 & 12 Henrys

5, 10, 15, 20 & 25 Henrys

10, 15, 20, 25 & 30 Henrys

Follow this link to the MultiChoke section of Mercury's catalog.

Mercury's MultiChoke come in 3 sizes* with these center-hole-to-center-hole mounting dimensions:

"Micro" = 2 inches

"Mini" = 2-13/16 inches

"Large" = 3-9/16 inches





LostInRockFormations
Posts: 36
Joined: Fri Oct 05, 2012 12:00 am

Fri Oct 05, 2012 4:32 pm

Found this topic by searching online,

I have just bought a HT5R with the mercury upgrades,
the previous owner had already taken the old transformer out so I dont know where the wires went.
I have an output transformer and choke to fit, the choke looks easy, just replaces r10 ?

But after reading this it seems my HT5 is different,
in particular there is a connection to the power switch that isnt mentioned here,
and
"The connections to the tube are soldered on...and need to be desoldered ... the wires are close so be careful not to burn other wires...."
seems wrong, I cant see any wires close to the tube socket and no sign of desoldering.

Can anyone help with guidance for the amp I have ?

I am Ok with soldering and reading diagrams,
ideally I would like a connect this wire to this and that wire there sort of guide.

Thanks.

BYN
Posts: 4
Joined: Fri Jan 17, 2014 11:29 pm

Wed Jan 22, 2014 3:06 am

Would have been nice if you'd have made some youtube clips of your upgraded amp. Its hard to tell with amp mods. To see "if" they actually make a difference or if this is just snake oil.

BowerR64
Posts: 22
Joined: Sun Jul 19, 2015 5:08 am

Thu Jul 23, 2015 8:03 am

I wont know yet till i get a new power tube if i have a bad OT but im not sure i udnerstand this.

The power tube sends the output to the transformer and then the transformer just ups the output.

I dont understand how the larger transformer helps.

I understand that it might up the power but how is it changing the sound?

When i look at the OT, i see to leads coming off the output tube and goes straight into the OT then the 3 leads come out and go into the output board.

User avatar
thephantum
Posts: 1160
Joined: Wed Jan 29, 2014 7:42 pm
Location: Virginia, United States

Thu Jul 23, 2015 4:04 pm

Output Transformers don't "up the output". The OT steps down the voltage to increase current in order to "match" the tubes to the speakers. Technically speaking, total output vs. input of the OT is slightly lowered as some power is lost during the conversion as heat. :mrgreen:

It's not a matter of the Mercury OT being bigger so it sounds better. It's about why it's bigger. In other words it's construction. How the core is constructed, how thick or thin is the wire, how many primaries, how many secondaries, how many turns in those winding's. More winding's means thinner gauge wire, which makes for better frequency response...but also reduces the total power output. So it's a balancing act and while there's a lot of physics involved, a good sounding OT is much more art than science.

So the stock OT in the HT5 might have 3 primaries and 2 secondaries (8 & 16 ohm)...but it's much more likely that it only has 2 primaries with a single secondary that has two taps. That would be the most cost efficient build. My guess is that the Mercury Magnetics OT has at least 4 primaries and 3 secondaries because it has three taps (4, 8 & 16 ohm)....so it has more windings, with thinner gauge wire, more primaries, dedicated secondaries, better core material AND, most importantly, the expertise of only building transformers specifically for guitar amps. All that means a better frequency response and better overall sound but at a lower output level. So the OT needs to get bigger to handle the power.

I actually installed a MM in my HT-20. It doesn't change the sound per se...it enhances the sound. The highs are crisper, the lows are more defined and the mids have more clarity, definition and punch. When I got it a few years back, the OT for the HT5 was around $180 + shipping (vs. the HT20 version which $128 shipped to my door). The HT5 OT is now $207 + shipping. While it will make the amp sound better...remember, this is a 5 watt output stage. I personally use mine as a practice amp. So I'm not sure it's worth it. Especially when you can get a factory replacement OT for $16 + shipping: http://www.guitar-parts.com/catalog/bla ... mcpts02006

BowerR64
Posts: 22
Joined: Sun Jul 19, 2015 5:08 am

Fri Jul 24, 2015 5:52 am

Is there one inbetween the stock one and the MM ? One that is slightly better then stock but not a $200. transformer.

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thephantum
Posts: 1160
Joined: Wed Jan 29, 2014 7:42 pm
Location: Virginia, United States

Sat Jul 25, 2015 5:09 am

Not that I'm aware of.

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8len8
Posts: 81
Joined: Sun May 08, 2016 8:26 pm

Sun May 08, 2016 8:31 pm

thephantum wrote:Output Transformers don't "up the output". The OT steps down the voltage to increase current in order to "match" the tubes to the speakers. Technically speaking, total output vs. input of the OT is slightly lowered as some power is lost during the conversion as heat. :mrgreen:

It's not a matter of the Mercury OT being bigger so it sounds better. It's about why it's bigger. In other words it's construction. How the core is constructed, how thick or thin is the wire, how many primaries, how many secondaries, how many turns in those winding's. More winding's means thinner gauge wire, which makes for better frequency response...but also reduces the total power output. So it's a balancing act and while there's a lot of physics involved, a good sounding OT is much more art than science.

So the stock OT in the HT5 might have 3 primaries and 2 secondaries (8 & 16 ohm)...but it's much more likely that it only has 2 primaries with a single secondary that has two taps. That would be the most cost efficient build. My guess is that the Mercury Magnetics OT has at least 4 primaries and 3 secondaries because it has three taps (4, 8 & 16 ohm)....so it has more windings, with thinner gauge wire, more primaries, dedicated secondaries, better core material AND, most importantly, the expertise of only building transformers specifically for guitar amps. All that means a better frequency response and better overall sound but at a lower output level. So the OT needs to get bigger to handle the power.

I actually installed a MM in my HT-20. It doesn't change the sound per se...it enhances the sound. The highs are crisper, the lows are more defined and the mids have more clarity, definition and punch. When I got it a few years back, the OT for the HT5 was around $180 + shipping (vs. the HT20 version which $128 shipped to my door). The HT5 OT is now $207 + shipping. While it will make the amp sound better...remember, this is a 5 watt output stage. I personally use mine as a practice amp. So I'm not sure it's worth it. Especially when you can get a factory replacement OT for $16 + shipping: http://www.guitar-parts.com/catalog/bla ... mcpts02006
Just saw this. How did you know which wires went where for the HT-20 transformer replacement?

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