New to me Mark I!

[Central Scrutinizer]

I just picked up this 1977 Mark I:

Good price. Initially, very disappointed. Sounded like crap! Not having any Boogiexperience, I posted on another forum for help. Some useful stuff.

First, the reverb tank was not secured other than 2 oversize wood screws that were not screwed in more than 1/4 of the way. I put proper screws in it, but no avail, it screamed with the slightest setting with feedback. Sounded so-so with no reverb.

Well, I felt something in the grill. All screws securing the speaker were completely loose and the speaker almost fell out when I removed the grill.

I was most disappointed. I screwed it back in. Still the reverb problem. Pulled the chassis- found a 12AX7 in the reverb. Switched it for a 12AT7 and KaCHING! What an amp!

I just put down my '57 Junior and have just been floored! Great sounding, versatile, and LOUD! I've been having a blast with it.

Here's some gut shots:

Couple of questions:
1. What is the 1/4" Jack between the reverb inputs for in the last photo?

2. Does it appear all original?

Sorry for such basic questions, but I'm just not that familiar with the Boogies.....but I want to be!

Thanks for any help.

Darren.

 

[jonarobb]

Looks fantastic. Nice to see those low value B+ caps off the rectifier with the additional cap off the standby switch. With the exception of one single metal film dropping resistor, it looks completely all original. Very impressed...

That 1/4" jack on yours looks to be wired in line to the Phase Inverter which would mean it's for Preamp Out. I've seen so many Mark I's and that jack is usually wired one of 3 ways:

Preamp Out

Reverb and/or Graphic EQ On/Off

Pull Boost On/Off

 

[Central Scrutinizer]

Thanks for the reply.

I'm hoping its a reverb switch. Whats the best way to find out? I'm guessing a good tech, but I don't know one locally. Would another picture help?

There is a faint crackling (like firewood) with high gain (and volume) at the low end that happens mainly with my humbucker guitars, but otherwise, a really nice amp.

I'm stoked with it! Especially with my P-90 equipped guitars!

Darren.

 

[Central Scrutinizer]

One more question-

Where can I find the serial number. I was told it was in the 300's.

Darren.

 

[JOEY B.]

One more question-

Where can I find the serial number. I was told it was in the 300's.

Darren.

Right below the speaker jacks. It should begin with the letter "A".

 

[Central Scrutinizer]

It's A 836.

The speaker jacks aren't labeled. Is it (from left to right as your looking at it 4-8-4 ohms or 8-4-4 ohms ?

Thanks.

Darren.

 

[Central Scrutinizer]

Oy! Anyone own one of these that can answer my speaker out question above?

Thanks in advance!

 

[jonarobb]

8-4-4 (l-r)

 

[Central Scrutinizer]

Really lovin' this amp! I'm impressed with the subtle sounds that can be coaxed from the right hand. Very good range. The Altec sounds a bit shrill at high volume and gain and really wobbles on the low end, but when I plugged into my 4x12 Marshall cabinet, that went away. I can't imagine playing at that volume as this is by far the loudest amp I've played.

Another question:

The reverb unit was mounted on the floor of the amp. I read (and there are mounting holes) that the reverb was mounted on the back panel, off the floor to prevent vibration.

Should I re-mount it on the back panel, or elevate the amp on a stand?

Gracias! Great to be a Boogie owner! I'm stoked!

 

[JOEY B.]

Try one of these with the MkI, as it can help when you jack up the pre-tone stack gain controls.

http://www.pedalgeek.com/cgi-bin/new_shop.cgi?config=&uid=S4nx3AAA1226022657&command=link--aess

 

[lyman]

Try one of these with the MkI, as it can help when you jack up the pre-tone stack gain controls.

http://www.pedalgeek.com/cgi-bin/new_shop.cgi?config=&uid=S4nx3AAA1226022657&command=link--aess

Hey Joey B. - I've often wondered about those things. They work pretty well? Have you tried it with a bunch of amps? Interesting concept.

 

[Pablomago]

If you have a sound like firewood crackling, it's possibly a preamp tube getting ready to give up the ghost. You might try some know good tubes and see if they make a difference. My MK I RI was making hissy sounds, then it started distorting when I was playing and the volume dropped. Preamp tubes.

 

[Central Scrutinizer]

So, where are your reverb units mounted on your Boogies? I think mine has been re-mounted wrong on the floor. Shouldn't it be on the back panel?

 

[jonarobb]

So, where are your reverb units mounted on your Boogies? I think mine has been re-mounted wrong on the floor. Shouldn't it be on the back panel?

There's no rhyme or reason 2 it. You can take 10 Mark I's from 1977 and half of them will have the tank mounted on the back panel and the half will have it mounted on the bottom of the cab. I notice pretty consistently that 78'-80' combos had the tank mounted on the back panel exclusively. But like I said, there's no hard fast rule as with anything else regarding a Mark I....

If you have the original tank make sure the spring lock is completely notched in the unlocked position. Sometimes it comes loose and tends to rest on the springs.

Additionally, the small piece of foam that acts as a bumper for the springs in the tank, this tends to break down over time and becomes a goopey mess. If this decayed foam has gotten onto the springs then you need to change the tank....

 

[Central Scrutinizer]

So..

I took the amp to a tech here locally. I was not able to consistently dial in a sound. At times, it was perfect. Other times it crackled and hissed.

The tech replaced 6 caps, cleaned it up and said it sounds like a new amplifier. He said everything looked original and had just run their course. Currently, it is stocked with JJ tubes and he recommends replacing them although they are working fine.

Any suggestions on tubes? I get the amp back tomorrow and I'm really excited about it. It sounded so good before, just inconsistent from one time to another.

 

[Central Scrutinizer]

Well, my amp is back and sounds wonderful through my Marshall 4 x 12 cabinet. When pushed at volume or high gain through my Altec, though, it crackles and buzzes on the low E and A strings. I'm pretty sure it's the speaker.

I am looking for a replacement speaker. Over at Birds and Moons, it was suggested to try a Weber Michigan ceramic with paper dome. I play mostly blues.

Couple of questions:

1. How might I get the Altec repaired? We don't have anyone local that I know of.

2. I'm having a flamed-maple cabinet and a 1 x 12 matching extension built for it, so I'll need a speaker anyway.

Any suggestions are appreciated. I'm really loving the tone from this amp and bonding well (as long as I'm playing through my 4 x 12!). It's my first all tube amp. Previously, I was playing through a Vox ADVT 60 watt head. Not a bad modeling amp and I'd highly recommend them, but the Boogie just pegs the blues!

Darren.

 

[acorkos]

1. How might I get the Altec repaired? We don't have anyone local that I know of.

I would contact Orange County Speaker: OC Speaker website

I am looking for a replacement speaker

I put an Eminence Delta Pro 12A in my IIB (the JBL K120 it came with was too raspy with the amp overdriving). I tried an Eminence Tonker, which was better, but the Delta Pro 12A is perfect.

Eminence Delta Pro 12A Specs

 

[Central Scrutinizer]

Great info. Thanks.

Repair on the Altec looks to be around 150 bucks. Not knowing much about speakers, is that worth it?

The Eminence Delta 12 is only 105 dollars.

 

[acorkos]

it's probably a fair price (those guys are good, if not one of the best)....but paying for shipping both ways is going to bump up the cost.

OC Speaker is driving distance from me...I use them when i need reconing services.

when repairing vintage speakers, you have to go with someone with experience and a good reputation....which helps in preserving the value/collectability of the speaker, as well as restoring the intended sound of the speaker. it's easy to do it wrong.

Also, check out Weber speakers....he's got a tech registry page of techs in texas, some of whom do reconing:

http://www.tedweber.com/recone/

http://www.webervst.com/techreg/texas.htm

 

[Snottyboy]

Congratulations on the Mark I! Very cool looking (and sounding, I'm sure). I love the old Boogies!