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Temp "Time Format" issue Fix in Discussions

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Author Topic: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod  (Read 48837 times)

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Iperfungus

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #90 on: Time Format »

Fight!  Fight!  Fight!....

 :lol: :lol: :lol:
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herbyguitar

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #91 on: Time Format »

No fight. Just trying to limit other posts to relevant stuff. I know. That's an oxymoron because a lot of the time I'm not relevant
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MikeB

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #92 on: Time Format »

In this case it may well be relevant. It seems that you are having a similar issue to both Max and I and we have done the same mods as you. I'll certainly be watching with interest.
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Iperfungus

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #93 on: Time Format »

In this case it may well be relevant. It seems that you are having a similar issue to both Max and I and we have done the same mods as you. I'll certainly be watching with interest.

Yep.
That's what I said some posts ago: 3 MP1s, same mods, same issues.
Issues that are related to this topic.

I discussed this issue privately with Phil/Mjmp several times and we made different hypothesis.
Now, after you guys reported the same issue, Phil had an idea and made an assumption about MDRT and tubeboard that makes sense (as usual, speaking about him).
I'm sure he's already testing the possible solution and he will be back with results soon.
Then, shouldn't this be enough, there's something more he suggested me to do during our discussions and that I didn't do yet (an OP AMP and 4 caps to be replaced): I would wait for Phil's results now.

By the way, if Herby prefers, as I said I can open a new topic and we can go on there.
Just let me know!
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herbyguitar

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #94 on: Time Format »

No. You don't have to open a new thread. Like you said. It's all related 
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Iperfungus

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #95 on: Time Format »

No. You don't have to open a new thread. Like you said. It's all related

 :thumb-up: :thumb-up: :thumb-up:

Usually this approach produced good results for other people in the future.
A common issue solved is a big added value!
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Iperfungus

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #96 on: Time Format »

Up!  :lol:
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Iperfungus

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #97 on: Time Format »

I'm also having similar issues. Max had been asking me to quantify my squeal but i haven't had an opportunity to get all scientific about  it. With my b200s out  of action, i have been using the mp1 with a cab sim and  going out to pa speakers. My higher gain patches became unusable. Even Turning the gain down a bit hasn't really helped and then if it did , it's not really the solution I'm looking for.  I will try to spend some time this weekend mapping out the limits of the squeal.

Hey Mike....did you run any other test with the squeal issue with high gain settings on your MP-1?
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MikeB

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #98 on: Time Format »

Hi Max,
Yes I did.  I didn't write anything down, thinking that I would remember, but of course I didn't.  So, I have just rerun some tests.
I have done this with both of my guitars.  I have done this with richards carvin ts100 as well as with my b200s.  I have even done this using a gcs-3 in the effects loop and going out to a headphone amp which pretty much proves that it is not a feedback issue.  I have done it with my gmajor2 in-line and active, in-line and bypassed and finally just going straight from my mp1 to the b200s.

I have an mdrt, noise mod and SS tube board.  I have a mullard short plate in 1 and Boogie STR in 2.

At one stage I used the gmajor2 parametric eq to isolate the frequency (but unable to completely eliminate).  It seemed to be at around 3000hz (this is the bit that I may have forgotten - Richard can you remember if this is what I said?).  Richard said it was around the Presence mark on the spectrum.  For the record, my mp1 is set up pretty flat.  Treble and presence are both 0, bass and mid not far away.

My main lead patch has OD1, OD2 and MV set at 6.5.  If any of those are higher then the squeal is present.

1. Keeping OD2 and MV at 6.5.  Adjusting OD1, the squeal is noticeable at 7.0 getting worse as the level goes up.  It is significant at 8.0
2. Keeping OD1 and MV at 6.5.  Adjusting OD2, the squeal is noticeable at 7.0.  Significant at 7.5
3. Keeping OD1 and OD2 at 6.5.  adjusting MV, the squeal is noticeable and significant at 7.0
4. OD1 on 10, MV at 6.5.  Adjusting OD2.  Noticeable at 5.5, significant at 6.0
5. OD2 on 10, MV at 6.5.  Adjusting OD1, Noticeable at 4.8, significant at 5.5
6. OD1 and OD2 on 10.  Adjusting MV, detectable at 5.0, significant at 5.5.

I quite like the tone that I can get even with these restrictions as it is so much better than it was before I did all the mods.  However, it seems crazy to be restricted to 6.5 on a scale that goes to 10.

MJMP, I am prepared to be the guinea pig for the resistor change, if you can tell me what I need to change.

Herby and Max, does this sound like the problems that you are having.  I had pretty much not thought about it for a long time because when it first started happening, I didn't map it out as completely as I have just done and MJMP said to just not put the levels up so high.  In retrospect, I should have pushed the point, as 6.5 is not really what I would call high.

cheerio,
Mike :waving-banana-smiley-emoticon
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herbyguitar

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #99 on: Time Format »

Your diagnostics sound about right to me as far as gain goes. I also agree with the limitations. My hum however is a lower frequency. more in the lower mids.
If it can be fixed without shipping it off to MJMP it would be preferable since he's in Europe and I'm in the USA. Shipping cost to Europe is crazy.
« Last Edit: Time Format by herbyguitar »
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MarshallJMP

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #100 on: Time Format »

Try to set the OD1 (T2) trim pot all the way down. See what that does.
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herbyguitar

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #101 on: Time Format »

T2. Trimpot 2 on the board pic? Or is that the one by the tubes... on the main board sort of between the tubes?
« Last Edit: Time Format by herbyguitar »
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MarshallJMP

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #102 on: Time Format »

It's the one on the left side closest to the front panel.
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Iperfungus

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #103 on: Time Format »

Hi Max,
Yes I did.  I didn't write anything down, thinking that I would remember, but of course I didn't.  So, I have just rerun some tests.
I have done this with both of my guitars.  I have done this with richards carvin ts100 as well as with my b200s.  I have even done this using a gcs-3 in the effects loop and going out to a headphone amp which pretty much proves that it is not a feedback issue.  I have done it with my gmajor2 in-line and active, in-line and bypassed and finally just going straight from my mp1 to the b200s.

I have an mdrt, noise mod and SS tube board.  I have a mullard short plate in 1 and Boogie STR in 2.

At one stage I used the gmajor2 parametric eq to isolate the frequency (but unable to completely eliminate).  It seemed to be at around 3000hz (this is the bit that I may have forgotten - Richard can you remember if this is what I said?).  Richard said it was around the Presence mark on the spectrum.  For the record, my mp1 is set up pretty flat.  Treble and presence are both 0, bass and mid not far away.

My main lead patch has OD1, OD2 and MV set at 6.5.  If any of those are higher then the squeal is present.

1. Keeping OD2 and MV at 6.5.  Adjusting OD1, the squeal is noticeable at 7.0 getting worse as the level goes up.  It is significant at 8.0
2. Keeping OD1 and MV at 6.5.  Adjusting OD2, the squeal is noticeable at 7.0.  Significant at 7.5
3. Keeping OD1 and OD2 at 6.5.  adjusting MV, the squeal is noticeable and significant at 7.0
4. OD1 on 10, MV at 6.5.  Adjusting OD2.  Noticeable at 5.5, significant at 6.0
5. OD2 on 10, MV at 6.5.  Adjusting OD1, Noticeable at 4.8, significant at 5.5
6. OD1 and OD2 on 10.  Adjusting MV, detectable at 5.0, significant at 5.5.

I quite like the tone that I can get even with these restrictions as it is so much better than it was before I did all the mods.  However, it seems crazy to be restricted to 6.5 on a scale that goes to 10.

MJMP, I am prepared to be the guinea pig for the resistor change, if you can tell me what I need to change.

Herby and Max, does this sound like the problems that you are having.  I had pretty much not thought about it for a long time because when it first started happening, I didn't map it out as completely as I have just done and MJMP said to just not put the levels up so high.  In retrospect, I should have pushed the point, as 6.5 is not really what I would call high.

cheerio,
Mike :waving-banana-smiley-emoticon

Thanks for testing Mike!
I 100% agree with you about all the better tones you get from MP-1 after those mods.
And I also agree with you that the squeal is not a feedback, also because I use home volumes here and it's there anyways...
It looks more like an oscillation, as MJMP suggested as well.

About the squeal, I get it with the settings of my main patch:

OD1 = OD2 = 7.5
MV = 5.5
Bass = 6
Mid = 6
Treble = 9
Presence = 12

I really love these settings, since the preamp has a very "plexish" tone...lot of details, no compression, tons of gain and open sound.
I loved it this way before mods and I love it more after mods.
The only problem with these settings is the squeal that comes out if I turn the front Output Level over 10-11 'o clock.
I did similar testing as yours and, at the moment, I can get rid of the squeal in 2 ways (without lowering overall gain, of course):

1) lowering Output Level (this means I cannot run outputs as high as I like)
2) lowering the EQ (this means I cannot have that "plexish" tone)

If I lower OD1-OD2-MV and EQ (bass, mid, high, presence) I can set Output Level to max without any squeal...but that's not MY tone.  :lol:

Internal trimpots for OD1 and OD2 have been set to minimum value already, after mods.

I also discussed the issue with MJMP by email and about the resistor he suggested to add a 100K resistor in series to R17 on the tubes board (430K --> 530K), to lower the input voltage of digital pots.
R17 is the more "external" of a group of 3 resistors in front of V2 socket.
As always, I'm very busy in these days and I did not find the time to do the job yet...but if MJMP confirms and you Mike would be the first one to do it....you're more than welcome!!!  :bow: :lol:
MJMP suggested to replace some other components at first, but now I would attempt the R17 mod before doing anything else...otherwise we'll never know if it worked 100% to solve the issue...

A couple of questions: did you find any difference about that squeal with different tubes? I attempted some tubes rolling as well but I found no differences.
And how do you set front Output Level pot's value?

Another test I've done is to use loop send or headphones out (stereo with an insert Y cable) instead of main outputs: in this way, if I set front Output Level pot to zero and I use loop's level pot or headphones level pot, there's no squeal even with my settings....but, as I turn Output Level pot over 10-11 'o clock, the squeal is there...even if I'm not using main outs.
This makes me assume MJMP could be right about oscillation and a too high input voltage somewhere.
« Last Edit: Time Format by Iperfungus »
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herbyguitar

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Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
« Reply #104 on: Time Format »

I wonder if the 3K hum can be related to the mid hum in some way. The only other mod I did aside from the mods that the others have done is the bass trim pot mod...
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