EHX Forums

New member, just got a Sovtek Mig100H, questions.

2012-05-16T08:34:30-05:00

Hello all and greetings, I’m a new member here to the forum, been a lover of all things EHX over the years. I apologize for the long dissertation here in advance, but I’m a technical sort of guy and figure this is the place for it.

I recently acquired a mint condition Mig 100H head off a local craigslist for a pretty good price. I know that EHX was resposible for bringing these amps into the country from Russia in the 90’s. I normally play an Orange Rocker 30 which I love very dearly, but just wanted something a little different, and something that could act as a solid backup amp. I wish I could afford a nice Marshall JCM 800, but I just couldn’t justify dropping that kind of cash, as my band only plays out once every couple of months. So after reading all the comparisons of the Mig100H to the JCM800, I found one for sale locally and went for it.

Anyway, the only info I’ve been able to find on the Mig amps is mostly from user reviews over at Harmony Central. I have been able to fire the “beast from the East” up several times at band rehearsal and put it through its paces, mostly in the high input/ high gain application. I generally run Gibson Standard LPs into it and am running the head through an 8ohm Framus 4X12 w Celestion V30s.The only pedals I use are a Vox wah and a Fulltone Fatboost for the occasional solo boost. I pretty much stick with high gain all the time for the style of music that I play, which is sort of 70s inspired punk/hard rock, not metal, but some songs we do are “early metalish”. Basically its just riff rock. If I need “clean”, I just roll the volume off on the guitar.

Here’s a couple of questions:
A) the amp has 5881 power tubes currently in it, will it accept EL34s as is, or can it be modded to accept EL34s? Would switching to EL34s “sweeten the tone” in other words, make it more “Marshally”, more British?

B) is it possible to pull two of the power tubes, either the outer pair or the inner pair, to cut the 100watts down to 50? Would this hurt the amp?

C) when plugged straight into the high input, with a LP, the Volume knob to my ears has no affect on the sound whatsoever. What I mean is that I notice no difference in the amount of gain/distortion when the knob is turned. It has a Master Volume knob as well. There is basically just one gain setting, which I would describe as GnRish, not metal, but definitely hard rock distortion. There are a few songs where I would like to be able to back the gain off a bit on the amp, for a more 70s classic rock sound. Could there be something wrong with the volume pot?

D) the amp seems to take a very long time to warm up, before it starts to really sound good. I’m talking about an hour or so. If I let it warm up for 20 min or so before hitting the standby switch and I start playing, I notice an intermittent volume sag from the amp while I’m playing, after about an hour this goes away and the amp starts to sound quite a bit better, juicier, not sure if its just the tubes getting nice and hot or what.

Perhaps it just needs a good tune up and biasing?

I know a very good tube amp repair tech, who works out of his house for reasonable rates. He’s done great work for me in the past, I plan on having him take a look at the amp, but would like some info to take to him.

Thanks for any help!

Bad Stone wiring help?

2009-05-29T22:57:48-05:00

I bought an old Bad Stone off ebay, and it’s completely shot (I have many many choice words for the seller and their “cosmetic blemishes but in working condition”).
There’s a broken capacitor and two disconnected wires—one from the ON/OFF switch and one from the bottom of the board.
I found a schematic, but that doesn’t mean a whole lot to me.
anyone have one of these and can tell me where these wires go? Or post a gutshot so I can trace your wiring?

Here’s the cap

Here’s the board with the broken wires:

Are those three nasty looking trimmers soldered onto the board stock or has it been badly modded ?

Little Big Muff EH SPI Info ?

2012-05-16T02:19:59-05:00

I have a Brown & Yellow Little Big Muff Pi version marked “EH SPI” on PCB.

I’ve already heard of the “EH 3034” and “EH 1322” PCB versions but never of this version.
By looking at the PCB, it seems to me that it is not an op-amp / IC based version but a transistor one.

Any information about this version, its date and how it relates to other BM and LMB version would be greatly appreciated..

Thanks for your expertise !!

Vintage Switchblade schematic

2012-05-16T00:31:59-05:00

Does anyone have a wiring diagram or schematic for a vintage Switchblade?

Sovtek Amps Anyone?

2009-03-27T13:42:07-05:00

I would like to start a topic about Sovtek Mig amps
Im wondering what the first year of production?
The reason why is I have an odd looking Mig 60. The tag on the chassis reads “005 1992” Does anyone have any
ideas here? 5th one produced in ‘92? It also has block lettering on the faceplate instead of the russian word in red script.
Everything else is the same as any other Mig 60 except for the faceplate. It has not been modified by anyone so its an original
factory job. (pic is inverted)

Ideas??

HOG 2

2010-11-07T22:23:25-05:00

Is there any insider information of the HOG 2’s development? With the recent release of the Freeze, it would seem probable for a new HOG to be on the horizon. I wonder if it would have new features or if it would just be a repackaged HOG in the new enclosure. Personally, either of those options sound great to me, especially if there is no need for the additional purchase of the Foot Controller for presets. Anybody?

EHX Blog: Muse’s “Hysteria” with Bass Big Muff Pi

2009-02-06T17:48:48-05:00

I just posted a groovy rendition of Muse’s Hysteria, played w/ Bass Big Muff Pi:

http://www.ehx.com/blog/muse-hysteria-with-bass-big-muff-pi

EH Digital Dalay Vintage - repair suggestions sought

2012-05-14T14:04:44-05:00

A customer has brought in an EH Digital Delay pedal, looks like late 1970’s. No Output. Signal is good to and from digital section. signal stops in analog output section at a chip whose markings have been removed. A schematic would help. Or any suggestions as to what the unmraked chip may be - I don’t think it is the compander as I have identified another unmarked chip as the NE57x. To be precise, this is the EH Digital Dealy with Magna Storage and Echo Chorus

POG2 - Not Saving Presets

2010-09-29T18:37:49-05:00

Hello there,

Having some trouble with my newly aquired POG2.
I dial in a setting I really like, then hold down the White button until the lights flash and it says it is saved.

However, when I disconnect power from the pedal (ie: to transport it to the gig), and replug it, all my presets have disappeared!

Am I doing something wrong? :/