This IIC sounds like crap

[Mahoner]

I got this IIC really cheap. But the tone is junk. The s/n is 118xx and it has the possibly forged MB on the chassis.(I don't know) The power tubes are Sovtek KT66 and the preamps tubes are EH 12AX7.

However, the amp passes the effects loop test.

I know quite a bit about electronics, so:

What should I look for internally, to verify the + mod?

Are the Mesa tubes the best bet for getting that killer sound?

Thanks in advance.

 

[Boogiebabies]

http://homepage.mac.com/mesamac/PhotoAlbum2.html

 

[Boogiebabies]

http://homepage.mac.com/mesamac/PhotoAlbum3.html

 

[axwielding1]

I'll bet a re-tube will do wonders... I've never heard a complaint of IIC tone... The KT66's may be the culprit....
Try str454's.....
ax. :twisted:

 

[Mahoner]

Thanks for the pics boogiebabies.

My amp has a bunch of resistors cobbled on to the v2 tube socket. My guess is so it passes the effects return test. Whoever did this had some knowledge, but it's not Mesa quality work, that's for sure.

Also, some of the wires have been pretty hot at one time. Like someone screwed up plugging in to the preamp out and/or power amp in connections.

As soon as I can afford it, I'll be sending the chassis to Mesa for a thorough going through.

The amp is a 60W combo w/reverb and an EVM 12L. Black Tolex with a cane grill.

I only gave $500, so the trip to Mesa will be worth it.

 

[Boogiebabies]

No problem.

Here is a big'ern of the V1 and V2.


http://homepage.mac.com/mesamac/.Pictures/IIC++/DSC00209.JPG

 

[Mahoner]

I hope this works. It's supposed to be a pic of my V1 and V2 sockets. It looks nothing like yours, Boogiebabies.

 

[Boogiebabies]

It is because it is an early IIC with the RP10 board. Not soon after, Mesa designed the RP11 and it was used in the last IIC's and the IIC+. The RP10 did not have traces for the loop like the RP11, so it looks in your case that it was done PTP straight to the pins. I call it the loop stack as the design basically stacks resistors. If it looks like the St. Louis Arch it is usually a IIC+, and it passed the loop test. A friend of mine has the exact IIC RP10 board and Mike B modded his in the same way to a IIC+. Otherwise, the RP10 and 11 are very similar. As far as the quality of work, it looks like a Mike B. working with what he had to create the loop circuit on an RP10.

 

[Mahoner]

Thanks for the great info Boogiebabies.

As you can probably see, the orange wire on the Mid pot, the yellow wire on the Lead Drive pot, and the yellow wire on the Master 1 pot have been hot. So this amp will be going to Mesa soon for a check up.

btw, What tubes would you recommend?

 

[RR]

MESA's STR415s, these are Sylvannia which the Mark Is and IIs were design after.

 

[Boogiebabies]

Thanks for the great info Boogiebabies.

As you can probably see, the orange wire on the Mid pot, the yellow wire on the Lead Drive pot, and the yellow wire on the Master 1 pot have been hot. So this amp will be going to Mesa soon for a check up.

btw, What tubes would you recommend?

I would bet that the pots had been changed as they should have been Buss wire. What you are seeing is Mike B. in a rush and using covered wire instead of how Mesa usually meticulously bent the buss wire to connect to the next pot. He can get sloppy with the iron. I had one where he changed out the EQ LDR and toasted the **** out of it. It had burnt wire covering all over. It still, however sounds superb.

Look at the iron burns on you pre board 30uf 500V cap. Sometimes a certain angle is neede to get at plate load resistors and instead of removing the whole board he just gets the job done with some collateral damage. I still think he is the greatest guy. After seeing these **** thing for 25 years, he now just gets it done.

 

[MesieBooga]

Thanks for the great info Boogiebabies.

As you can probably see, the orange wire on the Mid pot, the yellow wire on the Lead Drive pot, and the yellow wire on the Master 1 pot have been hot. So this amp will be going to Mesa soon for a check up.

btw, What tubes would you recommend?

I would bet that the pots had been changed as they should have been Buss wire. What you are seeing is Mike B. in a rush ans using covered wire instead of how Mesa usually meticulously bent the buss wire to connect to the next pot. He can get sloppy with the iron. I had one where he changed out the EQ LDR and toasted the sh!t out of it. It had burnt wire covering all over. It still, however sounds superb.

Look at the iron burns on you pre board 30uf 500V cap. Sometimes a certain angle is neede to get at plate load resistors and instead of removing the whole board he just gets the job done with some collateral damage. I still think he is the greatest guy. After seeing these **** thing for 25 years, he now just gets it done.

Who would have ever thought pictures would be taken of your work in the future...for the world to see on the not yet invented Worldwide Web! :shock: :lol:

 

[Boogiebabies]

The www has really been around for a while. I remember the Saab Network back in 1988.