WHY do the professional effectsdesigners come to this place?

Started by Lurco, March 17, 2004, 05:43:17 PM

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Gary

Casey, is your amp a Mig 50 or a Mig 50H?  The Mig 50H is different than the Mig 50 puretube has in his photo.  The Mig 50 is only slightly different than the classic JTM45/non-master volume Super Lead Marshalls. They have no master volume, just a volume I and a volume II.   I have one of the original series with the mis-spelling on it.  It is a great sounding amp.  It's blowing fuses now, even with tubes not in the sockets, so I have a rectifier or transformer issue.  Atleast that's what I think it is.  One day, I'll get around to fixing it.  

Any pointers on where to start looking, puretube?  It blows a fuse as soon as the mains switch is turned on.  I obviously have a short to ground somewhere, but there are no signs of arcing.

puretube

desolder the primary output-transformer wires*, pull out he power tubes, (*after having discharged the HV-caps), "boot" the amp: if it still blows the fuse, it`s the PS.
If not, we`ll have an output-transformer/powertubes- session.

casey

it has 2 inputs but a "gain" and a "volume" if my memory serves
me correct.
Casey Campbell

puretube

mine is not an "H" version, got 2 inputs, vol1, vol2, bass, mid, treb, presence knobs, like Gary described.

casey

whats the difference between the one with the "h" and the one without?
Casey Campbell

puretube

don`t know the diff.;
maybe Gary can tell;
b.t.w.: which mis-spelling?

Gary

The Mig50 "H" has a MASTER VOLUME control.  It came after the Mig 50 and has a volume control after the tone stack.  It has a gain control after the second preamp stage.  The Mig50 "H" was sometimes called the Tube Midget, since it was a little smaller than the older Mig 50.  The "H" model does have two inputs, but it has an input setup like the Boogie Mk I.  That is, the hot channel has an extra stage that feeds straight into the normal channel.  When you run into the normal channel, this extra gain stage is shunted.

From Blueguitar.org, here are the schems:

Mig 50 "H"
http://www.blueguitar.org/new/schem/sovtek/mig-50h.gif

Original Mig 50
http://www.blueguitar.org/new/schem/sovtek/mig-50.pdf

Look at how the inputs are wired.

Hope this helps!

Puretube,
My Mig50 has the white plastic Mains and Standby switches.  They mis-spelled Presence on the front panel.  It is labelled "Presense."  I am told this was fixed on later units.  Mine is a PCB, not wired point to point.  I have seen a few of these amps, and I have not seen the first one wired point to point.  They have ceramic tube sockets that are chassis mounted.  I bought mine for 200 USD new in the box.  I really wish Mr. Matthews would bring these amps back into production at a similar price point.

Thanks for the starting point.  I'll work on it soon.

RDV

...for the beer & the babes!

RDV

casey

mine must be the "h" version because it says "tube midget" on in.

it has a gain and master volume...

so what type of mod do i do on it so that i can use both inputs at
the same time?  or is this impossible with this amp?
Casey Campbell

puretube

casey: in your case that would take more effort than I can take time for
(in fact you`d have to rewire the jacks, and take the output from the first stage`s plate-cap not to the gridcircuit of the second tube, but to the same point where the second stage`s plate-cap goes...).

Gary: thanx for the misspelling info: didn`t know that.
Mine (2 of`em) are written correct /and for the rest are like your description.

Be assured that I have tried to persuade Mr. Matthews... but there seemed
to have been some issues with continuing quality-production of the transformers; (and they are the main price-factor).

But never say never!

casey

hey i wouldnt mind having one of those all-wood sovteks with the
all wood cab... those are cool... 8)
Casey Campbell

Gary

Quote from: puretube
Be assured that I have tried to persuade Mr. Matthews... but there seemed
to have been some issues with continuing quality-production of the transformers; (and they are the main price-factor).

But never say never!

I contacted EH/New Sensor about a replacement output transformer, in case that is the problem.  The replacement was somewhat expensive, so I understand why he is concerned with price.  Still, I would love to see these go back into production.  Keep chipping away, maybe he will find a clever solution to the transformer issue.

petemoore

Daffy has the most accurate pronunciation of the word professional.
 Because, ....Shpir,.   I.. ..I Am, a phphphphPhRoPHeshshional...
 I Phrophess to know more than the average Duck !!
Convention creates following, following creates convention.

puretube

What used to be the topic of this funny thread?  :?:  8)  :?:  :lol:

RDV

Quote from: puretubeWhat used to be the topic of this funny thread?  :?:  8)  :?:  :lol:
.ecalp siht ot emoc srengisedtceffe lanoisseforp eht od YHW

sdrageR

VDR