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moonmarkcus
Silver Member
Nicaragua
224 Posts |
 Posted - 06/10/2009 : 22:00:28
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I bought on evilbay a HM-2, but his sound doesnt convince me, and after opened I found a Mod on D6 and D7, D6 was replaced with an 1N4002 and D7 was jumpered...
Can someone explain me what kind of effect it supposed to do???
( A long time ago cctsim analize something similar with a DS-1 mod)
Is there any way to obtain an organic marshall distortion? or something like that? Im still searching ( p�ge by page on topics, search doesnt work fine) to found this mod or other with a better aproach .....
I hope your comments.... |
Edited by - moonmarkcus on 06/11/2009 03:54:19 |
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moonmarkcus
Silver Member
Nicaragua
224 Posts |
Posted - 06/10/2009 : 22:39:37
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Pictures here !!! ( including text about mod in backplate)
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Edited by - moonmarkcus on 06/12/2009 06:48:46 |
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ChristoMephisto
Platinum Member
Canada
1288 Posts |
Posted - 06/10/2009 : 23:55:21
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D6 and D7 form a kinda compression to clean up any noise, the original are a pair of Ge. Never got around to modding my HM2, kinda like the stock sound with single coils
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 06/11/2009 : 21:13:48
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D6 and D7 act as a simple noise gate. Signals between approx. -300mV and 300mV will not pass through the diodes.
The mod you described is not very technically sound, e.g. if you short D7 then it doesn't matter what type of diode is in D6, as it is shorted too.
In other words, if D7 is shorted, remove D6 completely too, it will have no effect at all.
I have a nice mod for HM-2 that is a bit complicated. It involves adding an extra tone control that decouples the mid from the high frequencies.
HM-2 uses 3 gyrators for the tone control but two are controlled by a single potentiometer which makes it inflexible.
I could explain it in more detail if there is enough interest.
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moonmarkcus
Silver Member
Nicaragua
224 Posts |
Posted - 06/11/2009 : 21:27:15
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So, Is it allowing to pass all noise???
For sure I�m interested in your mod...you can post here or if you prefer ( for all of us ) will open another topic specially for your mod...it will be nice to learn this.
What kind of diodes are the originals??? Can I use 1N34a?..I have some of them
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 06/11/2009 : 21:46:59
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Yes, if you short D7 it will pass noise but also fine nuances of the guitar signal.
I will post the HM-2 mod soon in another thread. |
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moonmarkcus
Silver Member
Nicaragua
224 Posts |
Posted - 06/11/2009 : 22:15:44
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Thank you ...you are awesome !!!
Another question....
Can I use a pair of 1N34a (Germaniun Diodes) to replace D6 and D7???
Which are the originals???? |
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 06/11/2009 : 22:31:56
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| Yes, 1N34a should do the job. |
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IM28
Copper Member
26 Posts |
Posted - 06/12/2009 : 21:35:35
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quote:
Originally posted by cctsim
D6 and D7 act as a simple noise gate. Signals between approx. -300mV and 300mV will not pass through the diodes.
The mod you described is not very technically sound, e.g. if you short D7 then it doesn't matter what type of diode is in D6, as it is shorted too.
In other words, if D7 is shorted, remove D6 completely too, it will have no effect at all.
I have a nice mod for HM-2 that is a bit complicated. It involves adding an extra tone control that decouples the mid from the high frequencies.
HM-2 uses 3 gyrators for the tone control but two are controlled by a single potentiometer which makes it inflexible.
I could explain it in more detail if there is enough interest.
Peavey uses the same technique for noise reduction in their tube preamps. It is switched in when the gain boost is used. It does introduce some crossover or zero-crossing distortion at low levels. It is most noticeable during the decay of notes, kind of a grainy, sputtering. |
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moonmarkcus
Silver Member
Nicaragua
224 Posts |
Posted - 06/14/2009 : 06:49:20
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I just changed D7 and D6 to 1N34a, it is quiet but doesnt have ( by far) a Marshall vibe!!!
Any idea to obtain that kind of sound.... |
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 06/14/2009 : 15:29:08
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I would try a red LED in D8 and a 1N4001 in D9 and D3.
You could also sort D5. |
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Topic |
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HM-2 MIJ with Mod
