• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Trace Elliot standby "pop" modification?

Bass-only

Bass-only

Oct 9, 2001
1,203
300
65
Cleveland
#1
I have an AH300SMX head that has the nasty "pop" when you throw it into or out of standby.

I understand that the newer Trace heads had eliminated that problem and that there is a modification that can be done to the older units to fix the problem.

Does anyone know what is needed? Is there a description or schematic available?

Any assistance is greatly appreciated!
 
#3
Okay - I just got the scoop straight from the Trace Elliot service folks (okay, Gibson!).

Prior to before 1996 many of the SMX preamps had the same problem. When you engage the standby switch after the amp has been on (and sat) for a while, a "pop" is heard!

It was common with the AH250SMX line, and made it into the first few AH300SMX heads also (before being caught and corrected).

There is a 1M resistor that needs to be connected between two points on the circut board. It can be done without removing the circut board and can be done in minutes.

If anyone wants the PDF with the details, e-mail me!
 
#4
Hallo Bass-only,
nice to meet you in the Talk Bass Forum. I have got the same Probleme with my Trace Elliot AH 250SMX Year `93.
Would you please so kind to send me the detail information as a PDF to me. My e-mail :
[email protected]

Thank you for these helpful information.
With kind regards
Gabriel
 
#5
I know this is an old post, but I also have had this trouble since day one with my AH250SMX. It is not a good thing to have the "pop" go into a house board, and then through the venue PA. (Through DI) The first, and only time it happened, I had the sound man say "What the **** was that!" I now always have to give a heads up that my bass channel needs to be muted between sets. I know it's a long shot, but hey Bass Only, do you still have this modification/information handy? Peavey, the new owner of Trace has no clues. I email Gibson recently about this mod. Don't know if they can still assist with the information. HELP!!!
 
#7
Thank you Bass-only for the pdf file. The modification is completed now. Simple, yes. I'll check the house PA at the next show that I do. Thank you also BassmanPaul for the added input. Seems as though you have knowledge on amplifiers, as I read in your profile. You guys helped me tremendously...
 
#8
Bass-only, Hello I joined this site for information about bass equipment just recently. I got the bug real bad. I saw your post about poping and said, OMG!!!. Thats exactly what my AH250SMX does & it drives me nuts and its embarrassing when I am out practicing. I thought it came damaged. It all makes sense now older trace made in the uk. Can you help me as well with a pdf. My email address is [email protected]. Did you fix the issue yourself? thanks for your time and effort. Mark.
 
#9
Does anyone know the watt value of the required resistor? Bass-only was kind enough to send me the Trace memo for the fix. The memo states "solder a 1M resistor (72-RM1M)".

I'll guess the "1M" means 1 megaohm, but no watt rating is given.

Any help would be appreciated.
 
#10
Bass-only said:
Okay - I just got the scoop straight from the Trace Elliot service folks (okay, Gibson!).

Prior to before 1996 many of the SMX preamps had the same problem. When you engage the standby switch after the amp has been on (and sat) for a while, a "pop" is heard!

It was common with the AH250SMX line, and made it into the first few AH300SMX heads also (before being caught and corrected).

There is a 1M resistor that needs to be connected between two points on the circut board. It can be done without removing the circut board and can be done in minutes.

If anyone wants the PDF with the details, e-mail me!
Click to expand...
 
#11
I have a AH250 smx that for the second time will turn on at the rear but the stanby switch wont engage (stay in when pressed) the pre-shape and other buttons are the same. I took it to be mended but i'd like to know what the problem is. If its a secondry internal fuse i could replace myself it would be better than spending money i dont have, or really need.
I'd really appreciate any idea's
Mark
 
#12
Bass-only said:
Okay - I just got the scoop straight from the Trace Elliot service folks (okay, Gibson!).

Prior to before 1996 many of the SMX preamps had the same problem. When you engage the standby switch after the amp has been on (and sat) for a while, a "pop" is heard!

It was common with the AH250SMX line, and made it into the first few AH300SMX heads also (before being caught and corrected).

There is a 1M resistor that needs to be connected between two points on the circut board. It can be done without removing the circut board and can be done in minutes.

If anyone wants the PDF with the details, e-mail me!
Click to expand...
Could you please email me the pdf to Scrattermark67@gmail
Thanks
 
#14
Bass-only said:
Okay - I just got the scoop straight from the Trace Elliot service folks (okay, Gibson!).

Prior to before 1996 many of the SMX preamps had the same problem. When you engage the standby switch after the amp has been on (and sat) for a while, a "pop" is heard!

It was common with the AH250SMX line, and made it into the first few AH300SMX heads also (before being caught and corrected).

There is a 1M resistor that needs to be connected between two points on the circut board. It can be done without removing the circut board and can be done in minutes.

If anyone wants the PDF with the details, e-mail me!
Click to expand...
 
#15
Hello Im not sure if my earlier attempt at mailing you was successful, if you could forward the PDF fix for popping amps I would really appreciate it. Had mine since 96, but has just started popping after a repair on a bad connection from transformer? to inner fuses and the connection to the circuit board. If you can help I'd be very grateful.
Mark
 
#16
Sounds like a NEW problem was created by the repair attempt that may be unrelated to the modification. There are many possible causes of pops.
 
#17
agedhorse said:
Sounds like a NEW problem was created by the repair attempt that may be unrelated to the modification. There are many possible causes of pops.
Click to expand...
The problem with no power except the fan, turned out to be a bad /corroded connection on the power cables that come from the transformer and connect to the circuit board. A small with electrical driver tap got it too start working partially. A spray of Servisol and all was well. However it wasn't turned on for long and once home with a longer period powered up I got the pop. I'm in touch with a guy who worked at T Elliot and he suggested a 1 megohm resistor across the switch. I dont have a PDF despite asking a couple of contributors. If anyone has the PDF pertaining to this I would be very grateful. Also I could rule out other possibilities by trying the fix suggested to me. Thanks Agedhorse or getting back to me and making me aware of the possibility of it being something else. Thanks
 
Last edited:
#18
I don't have a dog in this hunt, but if anyone does get the pdf, it would be beneficial for everyone to both take screenshots, and the pdf itself, and upload them to TalkBass as part of your profiles "Media".

That is to say, have the data / files actually hosted on TalkBass, rather than on a 3rd party website.
 
#19
Oneshoe said:
The problem with no power except the fan, turned out to be a bad /corroded connection on the power cables that come from the transformer and connect to the circuit board. A small with electrical driver tap got it too start working partially. A spray of Servisol and all was well. However it wasn't turned on for long and once home with a longer period powered up I got the pop. I'm in touch with a guy who worked at T Elliot and he suggested a 1 megohm resistor across the switch. I dont have a PDF despite asking a couple of contributors. If anyone has the PDF pertaining to this I would be very grateful. Also I could rule out other possibilities by trying the fix suggested to me. Thanks Agedhorse or getting back to me and making me aware of the possibility of it being something else. Thanks
Click to expand...
Don't spray anything on the primary connections, but too late for that. Fixing the problem is the safe and correct way to go about this. The residue will attract debris, dust and conductive bits which can result in an eventual safety hazard.
 

Latest posts

Top Bottom
Back