DIY AMI DD. Need some advice.

[Barclay]

I read the thread AMI DD project from 2011.

I just bought this on eboy and its been worked on by someone. The work looks clean.
I usually blow everything up, so i am hoping to get a little feedback advice here before i screw the pooch.
I know this is an old jukebox amp from the 40s or 50s, so it should have plenty of warm juice for my needs.
But I was hoping some of you could take a look at the work done and let me know what you think has been done to this.
I plan on putting together a cheap tube compliment just to get it running and focus on better tubes later on.
Someone recommended starting this up initially by gradually increasing the voltage to decrease damage risk and he said it would actually let the old caps relearn or stabilize and not blow? Is this true. Could I use a ceiling fan switch for this?
I was planning on running my moog and/or wurlitzer through this.

[Barclay]

Bump. Is it that noone has anything to say? Or are you just not interested?

[gingertube]

Barclay,
Hard to judge from the photos.

The replaced components look like they have been done OK but what worries me is that the components I would expect to be replaced by anyone knowlegable appear to have not been touched.

The first things which should have been changed are those 3 electrolytic capacitors in the cans which stick up from the top of the chassis. These are probably multisection capacitors . What we normally do for restorations is leave the old caps in place, put some tag strips under the chassis, wire replacement capacitors to the tag strips and then cut the wires from the old caps and move them to the new caps.

Try and find a circuit diagram.
Here is the Model C circuit which may help
http://www.angelfire.com/vt/audio/ami_ca.jpg

I went searching for the DD Model but since I'm at work the Goggle Safe Search is ON and "AMI" gets filtered from the search making it as useful as T.ts on a Bullfrog.

Cheers,
Ian

[Barclay]

Thanks gingertube. I almost did that for another project that is still on the shelf with all the new caps just sitting there. So I get the concept.
I see people talking about red caps. Are they better than the little blue ones or do they just look better?
Also, what is the risk of not changing them. I don't have my tubes yet, so I haven't fired it up.
I read another thread recommending a gradual voltage increase, like a variac, when starting up an unknown vintage device.
The quote was "I always use a variac to slowly increase the voltage into the amplifier, usually over about five minutes. This prevents blowing up things because the capacitors are not operating correctly. By slowly bringing up the voltage electrolytic capacitors are reformed and will normally operate properly as long as they're not damaged."
Kind of sounds like stretching out before excercise.
Can I use a variable cieling fan switch for this?

[Barclay]

Originally Posted by gingertube

Barclay,
The first things which should have been changed are those 3 electrolytic capacitors in the cans which stick up from the top of the chassis. These are probably multisection capacitors . What we normally do for restorations is leave the old caps in place, put some tag strips under the chassis, wire replacement capacitors to the tag strips and then cut the wires from the old caps and move them to the new caps.


Cheers,
Ian

I am really not technical enough, nor do I have the time to get that technical.
Do you know if one can order those cap/cans ?
I could do that replacement, but what you are decribing is a little out of my league and time contraints.
Thanks

[Barclay]

Well, I finally fired it up using a light socket in series. Started with a 40watt bulb for a five minutes with my phone playing pandora. Then 60 watts with my phone playing pandora then I hooked up the moog and it sounded great!

Like tony the tiger great.
It has a 120 vlt jack. Would it be a bad idea to wire a cooling fan to cool the caps