Mustang GT/GTX - Power Amp Upgrade Mod

Started by admin, April 21, 2020, 12:49:41 PM

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admin

I just did a deep dive and discovered the GT 100 / GT 200 use a IcePower Power amp.
(Based on the GT 100 Teardown video, I found a match )

And explains why Mustang GT Power amp sounds tighter vs old Mustang IV V2 Power Amp 
(Which tempts me to one day try an icePower 200AS2 Power Amp in a Mustang IV V2 Stereo 2x12" 



^ Mustang GT 40 with its Fender 20 x 20 Power Amp.

Mustang GT 100 / GTX 100 uses ICEPOWER 100AS1 Mono 100 watt power Amp Board
https://www.parts-express.com/ICEpower-100AS1-Class-D-Amplifier-Module-with-Built-In-Power-Supply-1-x-100W-326-260


https://icepower.dk/download/2431/
https://icepower.dk/download/1627/
100 watt @ 4 ohm Power  Amp / Power Supply Board



Mustang GT 200 uses  ICEPOWER 100AS2  Stereo 2 x 100 watt power Amp Board
https://www.parts-express.com/ICEpower-100AS2-Class-D-Amplifier-Module-with-Built-In-Power-Supply-2-x-100W-326-262

https://icepower.dk/download/2431/
2 x 100 watt @ 4 ohm Power Amp / Power Supply Board
QuoteContaining a capable fly back power supply with a continuous power capability of 100 W and a short-term power of 300 W, combined with a 2x 100 W class D amplifier. The 100AS2 is perfect for applications such as stereo hifi and home automation amplifiers, active speakers, studio monitors as well as 2 channel guitar or bass amplifiers without the need for forced cooling.
See IcePower Brochure
https://icepower.dk/download/1627/


(DO not Read below unless you are qualified)
------------------------------------------------
My plan for my 3 year old Mustang GT  -Power Amp Upgrade Mod

Install a ICE200AS2  STEREO power Amp Board


2 x @ 150W @ 4 ohm Power module,
https://www.profusionplc.com/parts/icepower200as2

https://icepower.dk/download/7088/


and a custom Output jack Board with TWO dual combo Speakon /1/4" Speaker output jacks and


Stereo XLR out and Stereo FX Loop
Found bulk of the parts on Ebay / Reverb - and I will use as basis for modifying as needed
Stay Tuned

admin

#1
I'm making progress on Mustang GT mods

Mustang GT200 MODS
Decided to use the new icePower 200AS2 power amp board in my Mustang GT200

Had to order the 200AS2 from Italy!
https://icepower.dk/news/story/200as2release/
https://www.ebay.com/itm/ICEPOWER-200AS2-2-X-200W-AMPLIFIER-AMPLIFICATORE-NUOVO-2-X-200W/184168061394

And after making the Mustang GT 200 Power amp upgrade, I'll use the left over 100AS2 stereo  power amp for a major upgrade to the Mustang GT40 Making it a "mini GT 200"

So I've modified both amps

Mustang GT200 -swap the stock 100AS2 stereo 100 watt icePower amp /supply board for a special ordered 200AS2 2 x 150 watt @ 4 ohm Stereo icePower amp /supply board


compare new larger 200AS2 Poweramp vs the original 100AS2 power amp, which still has its white Heat sink compound 
All I had to do was insure there was adequate new  Heat Sink compound on back of 200AS2 board
Before installing where former 100AS2 stereo board used to be, and there was adequate room on the large GT-200 chassis ( which acts as a heatsink ) and it bolted right in using original power amp mounting holes and screws


New 200AS2 Power Amp installed
All connectors are plug & play -no modification required

Already successfully booted up and updated firmware using the new 200AS2 icepower board as it also acts as main DC power supply for the entire amp

Next steps to complete the Mustang GT200 mods is swapping out the stock GT200 4 ohm 12" speakers for new 8 ohm 12" Celestion Hot 100 speakers. Fender factory ( GB in China) Glues these speakers to the baffle board, was a bitch to remove them, and the stiff paper mounting ring is slightly damaged - but these can be fixed, nothing else wrong with them
Speaker swap is required because the factory GT200 speakers are 4 ohm and would fry when being fed the wattage from the new 200AS2 power amp 
My end goal is  add stereo external speaker jacks -so I can run external 8 ohm closed back cabs-maintain total speaker load per channel  never dips below 4 ohms -where the icePower power amp develops its highest wattage

Completed Modified Mustang GT200  from rear

Just had a play through of my modified Mustang GT 200 for past 30 minutes
The amp is amazing, while just as loud as before as I'm running 8 ohms per side now
Mustang GT200 after my mods is now very open sounding and no speaker flubbing , even with Master cranked 3/4 up at 3:00 o clock ( its LOUD in STEREO!  and all functions still work - closer to an unobtainable Stereo Mustang GTX 200
I love the throbbing STEREO HARMONIC TREMOLO, and Stereo panning delays  - its a huge experience - way better than my mono Mustang GTX 100

And now with updated icePower 200AS2 Power amp , I can now safely add a pair of external speaker jacks for additional 8 ohm external speakers in closed back cabs for total of 4 ohm load per side -well within the operating specs of the icePower 200AS2 Power Amp



cheap Trick for instant smartphone stand when running Fender Tone app

Mustang GT100/GT200 owners-unscrew the handle with Allen wrench, Rotate the Handle 180 degrees

Now the flip up handle doubles as a small tablet /smartphone  holder stand for swift edits at gigs
The Amp has no limits now


Mustang GT40 MODS

I had originally planed to install the 200AS2 in the Mustang GT 40, but as you can see it would have been a very tight fit, so I decided the MUSTANG GT200 would be a more suitable use case for the 200AS2 power amp   



Compare Mustang GT 40 with its Fender 20 x 20 Power Amp ( top) vs icePower 100AS2 power amp (Bottom)  originally in Mustang GT 200
The remaining original GT200 100AS2 Stereo Icepower power Amp board I'll install in my GT40 along with a new set of high wattage SCAR 6.5" FX65-8 speakers which go 100Hz up to 8kHz (8 ohms @ 150 watts RMS )and preliminary test show these sound puncher for guitar tone vs the weak stock speakers
https://www.amazon.com/gp/aw/d/B07KW8R34W?psc=1&ref=ppx_pop_mob_b_asin_title



SCAR  FX65-8 Speaker(left)   Stock GT40 Speaker ( right) 

Scar FX65 has a much larger voice coil
The GT40 cab requires minor baffle board mod to accept the new speakers- but this should make the GT40 far more versatile
After these mods, with 100AS2 stereo  power amp and new speakers =  a major upgrade to the Mustang GT40 Making it a "Mini Mustang GT 200"
I'll also add external stereo speaker cab jacks
As both amps upon completion  will be far more versatile than stock
(To be continued after my pilot bearing router bit ARRIVES HERE

The Mustang GT40 CNC cut speaker baffle board cutouts are just 1/8" too small to accept the FX65-8 speakers , need to be opened up just a bit first.




admin

#2
Finally got the 100AS2 STEREO AMP Working on GT40

Fender implements a power on  MUTE circuit control logic , which is flipped between icepower equipped models vs the GT40 with its Fender designed power amp

Solution is disconnect the Amp Disable/  Mute control wire  pin #10 from P101 14 pin BASIC Control Connector.
Refer to icePower 100AS2 datasheet
https://icepower.dk/download/2431/

But I'm not done with the GT-40 mods yet, stay tuned

admin

#3

Inside Mustang GT 40



Mustang GT 40 Fender AMPLIFIER MODULE (2 x 20watt) Stereo Power Amp.


a Fender Mustang GTX 50 User shared an inside pic of the Power Amp board below


Fender Mustang GTX 50 Fender AMPLIFIER MODULE (1 x 40watt) Mono Power Amp.

Above Fender Power Amps are designed for 8 ohm minimum load

the GTX 50 employs a Fender Designed 40 watt Mono variation on the Fender Mustang GT40 Power AMP

and not the higher price / performance icePower Power Amp, exclusive to the GT100 / GT200 / GTX100


Fender Mustang GTX 100 ICEPOWER 100AS1 AMP

Same icepower 100AS1 Power Amp used in Mustang GT100 Power amp

Mustang GT200 uses icepower 100AS2 Stereo power Amp

admin

#4
Quote from: dazco, post: 32587126, member: 1963
Ohhhh, as Johnny Carson used to say, "i did not know that". What's your take on that compared to the GTX's PA as far as the tonal differences both is what kind of difference and how different sounding ?
All Mustang GT/GTX Amps use a Class D power amp, which alone are clinically cold laboratory type amps which faithfully amplify the signal on their inputs

Big Reason the Mustang GT/GTX Amps are very different than Katana 50/100/Artist Amps. Katanas Class AB Power amp plays a big role in the Katanas tone and feel, but like a tube guitar amp, the decibel level of the Katana amp plays a big role in the tone , Sag, and play feel.
Katana 100 W Head does not sound right until its really cranked  up ( just like a tube amp)

Katana, gets some of its distortion at higher volumes from the ST Micro TDA7293 Class AB DMOS IC output stage ( same type used in many Marshall MG series and Roland Cube 80 ), and along with a true Guitar speaker explains its guitar amp like tone  - very little DSP cab modeling employed on Katana
http://www.st.com/en/audio-ics/tda7293.html



By contrast, on the Mustang GT/GTX Amps, all the tone , play feel, sag , tonal character is 100% accomplished in the separate Fender DSP Board. they can get that tone at any volume (like a Fractal) -
Fender just uses the best cost effective means to create a line of amps at various wattages and price points. The Class D Power Amp employed is also the DC Power supply for the entire system, - including DSP board.

Based upon my teardowns of all Mustang Amps, its apparent they started with the GT 200 as the top tier design in R&D, which uses the icepower 100AS2 stereo power amp, as that includes the DC Power supply
https://icepower.dk/download/2431/

Then the GT100 uses the icepower 100AS1 100 watt mono Power Amp +DC Power Supply
https://icepower.dk/download/2431/

for the budget GT40 Stereo 2 x 20W amp, Fender designed their own Class D Power amp based on the

ST Micro TDA7492
https://www.st.com/resource/en/datasheet/cd00205863.pdf

But this Fender Power amp board has its own DC Power supply which uses same pinout as the icepower 100AS1 power amps.
Im sure the Fender designed power amp in GT40 / GTX50 meets a lower cost point, but is effective for its target category.


Mustang GT 40 Fender AMPLIFIER MODULE (2 x 20watt) Stereo Power Amp.

A Fender Mustang GTX 50 User shared an inside pic of the Power Amp board below


Fender Mustang GTX 50  Fender AMPLIFIER MODULE (1 x 40watt) Mono Power Amp.

Above Fender Power Amps are designed for 8 ohm minimum load


Top View



Bottom View

More details on the Fender AMPLIFIER MODULE Power Amp - used in GT40 (Stereo) GTX50 (Mono)


Its Based on the  ST Micro TDA7492
https://www.st.com/resource/en/datasheet/cd00205863.pdf

50 W + 50 W dual Bridge-Tied-Load (BTL) class-D amplifier

Features
* 50 W + 50 W continuous output power at THD = 10% with RL = 6  and VCC = 25 V

* 40 W + 40 W continuous output power at THD = 10% with RL = 8  and VCC = 25 V

* Wide-range single-supply operation (8 - 26 V)

* High efficiency ( = 90%)

* Four selectable, fixed gain settings of nominally 21.6 dB, 27.6 dB, 31.1 dB and 33.6 dB

* Differential inputs minimize common-mode noise

* Standby and mute features ( the Mustang Headphone out jack mutes the Power amp )

* Short-circuit protection

* Thermal overload protection

* Externally synchronizable

* ECOPACK®, environmentally friendly package

The GTX 50 employs a Fender Designed Mono variation on the Fender Mustang GT40 Stereo Power AMP+ DC Power board

An investigation of THD of a BTL Class D amplifier
https://ieeexplore.ieee.org/document/7527279

Compare

ST Micro TDA7492 datasheet above with the

GTX 100's  Icepower 100AS1 100 watt mono Power Amp. (Same as Mustang GT 100)
https://icepower.dk/download/2431/


The latest GTX Models are based on the Mustang GT, updated appearance, and updated speakers

ac30kev

Complete newb here on his first post.
I have a sort of relevant question concerning this.
Back story: I have 2 GT40's - great amps - but one got smashed to f@ckin bits (don't ask...)
My question is, do you have any details of the 2x20W power PCB as shown above, i.e. where the hell can I get one from (or even get one repaired at)?
I have contacted Fender and they are like not interested at all.
I've also contacted several service centres in the UK at Fender's behest and they aren't interested either.
Would it be easier to make a new cabinet, get some bigger speakers and create a FrankenMustang 100 (200??) watt monster as you have done?
Please can anyone give any advise?

admin

#6
Quote from: ac30kev on August 26, 2021, 10:59:35 AM
Complete newb here on his first post.
I have a sort of relevant question concerning this.
Back story: I have 2 GT40's - great amps - but one got smashed to f@ckin bits (don't ask...)
My question is, do you have any details of the 2x20W power PCB as shown above, i.e. where the hell can I get one from (or even get one repaired at)?
I have contacted Fender and they are like not interested at all.
I've also contacted several service centres in the UK at Fender's behest and they aren't interested either.
Would it be easier to make a new cabinet, get some bigger speakers and create a FrankenMustang 100 (200??) watt monster as you have done?
Please can anyone give any advise?

The Mustang GT40 power amp is a Fender designed unit built in China , and only available on the GB Assembly  line in China (Golden Bow Systems in China  builds many Fender, Celestion, KEF electronic products today

They do not sell this item as a replacement part to Fender service centers- big reason Mustang Amps are not popular when they fail

pacemaker1000

Sorry to hijack this thread.
Anybody help with adding what would be some sort of effects loop to a GT40.
The goal would be to use it as an active speaker for amp sims or pedals. Also separating the pre and power amps would enable the GT40 to be used as a standalone iOS/pc interface by muting the amps own guitar sound

fugas

Quote from: admin on April 21, 2020, 12:49:41 PMI just did a deep dive and discovered the GT 100 / GT 200 use a IcePower Power amp.
(Based on the GT 100 Teardown video, I found a match )

And explains why Mustang GT Power amp sounds tighter vs old Mustang IV V2 Power Amp 
(Which tempts me to one day try an icePower 200AS2 Power Amp in a Mustang IV V2 Stereo 2x12" 


^ Mustang GT 40 with its Fender 20 x 20 Power Amp.

Mustang GT 100 / GTX 100 uses ICEPOWER 100AS1 Mono 100 watt power Amp Board
https://icepower.dk/download/2431/
https://icepower.dk/download/1627/
100 watt @ 4 ohm Power  Amp / Power Supply Board



Mustang GT 200 uses  ICEPOWER 100AS2  Stereo 2 x 100 watt power Amp Board
https://icepower.dk/download/2431/
2 x 100 watt @ 4 ohm Power Amp / Power Supply BoardSee IcePower Brochure
https://icepower.dk/download/1627/


(DO not Read below unless you are qualified)
------------------------------------------------
My plan for my 3 year old Mustang GT  -Power Amp Upgrade Mod

Install a ICE200AS2  STEREO power Amp Board


2 x @ 150W @ 4 ohm Power module,
https://www.profusionplc.com/parts/icepower200as2

https://icepower.dk/download/7088/


and a custom Output jack Board with TWO dual combo Speakon /1/4" Speaker output jacks and


Stereo XLR out and Stereo FX Loop
Found bulk of the parts on Ebay / Reverb - and I will use as basis for modifying as needed
Stay Tuned
And there is a photo of the reverse side of ICEPOWER 100AS1?


AJNpa80

Greetings, first comment here, thanks for having me! I'm seriously considering swapping my 40 to the 100as2, especially to add the output board. I've searched through and prior to taking my amp apart, I wanted to ask where the take off for the Mustang 3 output module is. Is it on one of the existing fender boards or is it on the Icepower 100as2? I've zoomed into the pictures and maybe I'm dense but I couldn't be sure. I tried to make sure this wasn't a repeat question and apologize if I am missing something. I have the parts in a cart ready to pull the trigger and may pull my amp apart first to nose around. Thank you for your time.

Elantric

#11
I dont recomment the 100AS2 on Mustang GT 40

It physically does not fit the provided chassis real estate

Upgrading the Mustang GT40 to better speakers yeilded higher decibel levels

But its not going to compete with a loud drummer

In 2024, a NUX Mighty Space is a better purchase , as it has option to drive an external Speaker cab with its 60 watt power amp