Ok, a friend of mine emailed to ask about recapping an Altec 1588C. I told him I would open one or 2 up and take a look.  The only pic I could find in the interweb showed no elecrolytic caps. I have several of these modules that came in 1628a mixers.

I have one that the 1588c basically fell apart when I pulled it out. At the time I didn't really look to close at it because I was going to shelf this unit and work on it later. I took a look today and this module didnt look anything like the other pics on the web. This unit has small foil based caps that look elecrolytic and in this unit they were really looking bad. Also 3 of the transistors and some resistors were sealed up in a single package.

I then rememberd that several of the 1588c units were a bit shorter. 2 out of 3 of my 1628a units had a mix of short and long 1588c preamps.

I opened up one of the shorter units and they are built much differently. This one looks like it has some higher quality caps and all the transitors are exposed.

I could always hear a difference between the two, but I never really did any direct compairsons. The unit I use the most has the longer preamps in all slots except 1. However, this one has lead a good life and all the caps look healthy. This may explain why some ppl like the 1588c and others dont.

If you measure from the base (Minus the pins) the long uint is 1 15/16" the short unit is 1 1/4"

Here is some pics of both inside and out:

Long and short: 

Long guts on left, short on right: 
 

Long guts on left, short on right, note the transistors in the package for the left uint: 
 

Guts of a long uint, note the shape of the silver and red caps: 
 

Guts of a short unit, caps in these look a bit better quality:

A couple of folks requested some cap values for the long version, I guess I have been working on tube stuff too long. That one cap is actually 22uf, I had to double check. This one may sound pretty good if the caps were fresh.

Long 1588c Cap values: