ADA Depot Too - A Forum To Support Users of ADA Amplification Gear

Please login or register.

Login with username, password and session length
Advanced search  

News:

Lets get Technical > All Things Tube All about preamp and power amp Tubes.

Pages: [1]   Go Down

Author Topic: Checking for mods on new unit.  (Read 300 times)

0 Members and 1 Guest are viewing this topic.

wmacky

  • Newbie
  • *
  • Offline Offline
  • Posts: 5
Checking for mods on new unit.
« on: Time Format »

Love the 80's tone, and after watching a few recent YouTube demos I had to have one which I now do! I unfortunately missed the cheap pricing from not long ago. These are now running from $600 to $1000!   I got mine fairly cheap ( relatively speaking) for it's decent condition at $425. I was hoping for one that wasn't messed with to much.  I'm ok with transformer, and noise mods, but didn't want any tone changing mods  other than a possible 3 tube mod in the future :headbanger:

I have popped the lid, and it looks fairly clean / untouched inside with a exception.  The OD1 trim pot seems to have been replace with a much smaller and different style pot. Also a resistor the runs right next to that pot is replaced with a straight wire.  does that indicate some type of mod?
Are there mo
Logged

wmacky

  • Newbie
  • *
  • Offline Offline
  • Posts: 5
Re: Checking for mods on new unit.
« Reply #1 on: Time Format »

Well bad news for me.  Reading through information on this form, I have discovered that a mod was done  ( The high gain mod)   It appears this mod is not recommend for passive pickups, and that's what I prefer!  This was my fear and now it looks like I have a job to do.  >:(   I'm OK doing the unmod, but need help with the cap replacement  Not well versed in component ordering. I'll need to know what cap size/ type to get and if there is a polarity concern.

Here's the mod  -   http://adadepot.com/mods/ADA_MP-1_Stock_Gain_Mod_Doc.pdf
« Last Edit: Time Format by wmacky »
Logged

Aelfad

  • Newbie
  • *
  • Offline Offline
  • Posts: 29
Re: Checking for mods on new unit.
« Reply #2 on: Time Format »

Not to discourage you from demodifying it, but given that you wrote you might want to do a 3-tube version in the future, I suggest that you give the unit in its current state a chance. Granted, I haven't played the high gain mode myself - I have the 3TM version though. However, from what I know, 3TM changes the sound even more than any other mod, so it's unlikely you'll enjoy this ultimate version if _think_ the stock gain mod doesn't suit your passive pick-ups.
Logged

wmacky

  • Newbie
  • *
  • Offline Offline
  • Posts: 5
Re: Checking for mods on new unit.
« Reply #3 on: Time Format »

Perhaps, if others that have had the mod could chime in?   The biggest concern is the apparent need to now run a buffer ahead of any passive pickups to avoid " tone suck"

My favorite guitar tones are are early 80's NWBHM such as ( Late Judas Priest, Maiden, Early Def Lep,)  as will as somewhat higher gain Hair metal such as Ratt, Dokken, Cinderella.   Seems like the stock unit would suit best as I'm not into heaver gain death metal , or recto chug tones.

However if the gain could be dialed back with out much effect that would be ok, except for the new buffer requirement, and the loss of the clean tube channel I would assume?

A google search about this mod does not generate any hits. Is this a unpopular mod?
« Last Edit: Time Format by wmacky »
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4320
    • marshalljmpmodshop.net
Re: Checking for mods on new unit.
« Reply #4 on: Time Format »

Just reverse the mod, it's just a few components (5 resistors, a trimpot and a cap). if you need help finding these let me know, just need to know where you order parts from.

You need;

R90:1M ohm (all resistors 1/4W)
R92:510 ohm
R74:20k ohm
R19:510k ohm
R20:750k ohm
R21:270k ohm
Trimpot:20k ohm
C37:10µF/35V or 50V non polarized elektrolytic cap
« Last Edit: Time Format by MarshallJMP »
Logged

wmacky

  • Newbie
  • *
  • Offline Offline
  • Posts: 5
Re: Checking for mods on new unit.
« Reply #5 on: Time Format »

Hey,

Thanks so much! I was hoping you would chime in. BTW I'm in the US. I don't mind buying from Mouser, Digikey, Ebay, Amazon etc,

I'm much better at modding, and unmodding then parts buying.   I wanted to build up a small parts stash anyway, but don't want 10000 piecess of the same value!

 Resistors should be easy. Not sure if brand matters but was looking at this for the needed Resistors as well as additional stock.

https://www.amazon.com/gp/product/B07SFKCX6W/ref=ox_sc_act_title_2?smid=A9OSV9Q4YRG02&psc=1

Not sure about caps and best brands?   I would also like to do a recap while in there. Is a reacap always recommended? I see a ton of small electrolytics?   What is important?  Just the big ones?  Recommendations to purchase?

Lastly sizing that trimmer has be stumped, I can't  find one and I'm unsure how to size those, I know it's a 20K single turn?  I'll need help in how to readjust it too.



« Last Edit: Time Format by wmacky »
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4320
    • marshalljmpmodshop.net
Re: Checking for mods on new unit.
« Reply #6 on: Time Format »

Can't see what values are in that box, it needs to be a E24 series because else it won't have all values you need.

Send me an email so I can send you a list.
Logged

wmacky

  • Newbie
  • *
  • Offline Offline
  • Posts: 5
Re: Checking for mods on new unit.
« Reply #7 on: Time Format »

I can't seem to find your mail?

Hereare the vaules for the box. Seems to cover everything


1Ω,1.2Ω,1.5Ω,1.8Ω,2Ω,2.2Ω,2.7Ω,3.3Ω,3.9Ω,4.3Ω,4.7Ω,5.1Ω,5.6Ω,6.2Ω,6.8Ω,7.5Ω,8.2Ω,

10Ω,12Ω,15Ω,18Ω,20Ω,22Ω,27Ω,33Ω,39Ω,43Ω,47Ω,51Ω,56Ω,68Ω,75Ω,82Ω,

100Ω,120Ω,150Ω,180Ω,200Ω,220Ω,270Ω,330Ω,390Ω,430Ω,470Ω,510Ω,560Ω,680Ω,750Ω,820Ω,

1K,1.2K,1.5K,1.8K,2K,2.2K,2.7K,3K,3.3K,3.9K,4.3K,4.7K,5.1K,5.6K,6.2K,6.8K,7.5K,8.2K,

10K,12K,15K,18K,20K,22K,27K,33K,39K,43K,47K,51K,56K,62K,68K,75K,82K,

100K,120K,150K,180K,200K,220K,270K,300K,330K,390K,430K,470K,510K,560K,680K,750K,820K,1M.
« Last Edit: Time Format by wmacky »
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4320
    • marshalljmpmodshop.net
Re: Checking for mods on new unit.
« Reply #8 on: Time Format »

Yep resistors box looks ok.

I'll PM my email or you can find it on the left side of this box.
Logged
Pages: [1]   Go Up