The Chassis
The Blues Deluxe chassis looks very similar to the Hot Rod Deville chassis. It uses the same tubes, but with a slightly smaller power supply (due to the 40 watt vs. 60 watt rating) and smaller output transformer. It also has a slightly different channel switching arraingment, due to the two channel vs. three channel configuration. The following are pictures of the circuit boards after they were removed from the chassis, but before they were modded. This first picture is of the two boards - the main board, which consists of the power supply on the left, the power amp circuit in the middle, and the preamp and reverb sections on the right. The preamp and power tube sockets, and some associated parts, are mounted on a separate daughter board, which is connected to the main board by multi-conductor ribbon cables.
Circuit boards removed from the chassis
The next picture shows a closer view of the power supply end of the main board. The mod kit from Fromel (here) replaces all of the capacitors in the signal path, and also, the capacitors in the power supply. The power supply capacitors are replaced with caps with a higher capacitance, which helps to stiffen up the bass repsonse. Also, two large power resistors (lower right in the picture), whose job it is to regulate the +/- 16 volts for the relays, and the few ICs that power the reverb, as the originals are prone to over heating.
Main circuit board - left end
The right end of the main board is shown here. Again, the Fromel (here) mod will replace all of the signal path capacitors here. It will also replace the plastic input jacks, which you can see here in the upper right of the picture, with more robust Switchcraft jacks with a metal barrel. Insulating washers are used to isolate the metal jacks from the chassis, in keeping with the original design of the plastic jacks, which do the same thing.
By the way, one trick with these amps is to be sure to use a cable with a 90 degree jack at the end that plugs into the input jack. This prevents the jack from putting a large side load on the jack if it gets tugged. The plastic jacks would probably hold up better if this is done.
Main circuit board - right end
The sockets for the tubes are mounted on a separate board which, when mounted in the chassis, faces down so that the tubes stick out of the bottom of the chassis. A few resistors are also replaced here with the Fromel mod with some that have a higher precision rating. Here we see the two sockets for the 6L6 power tubes.
Tube circuit board - left
This next picture shows the three smaller tubes (two 12AX7s and one 12AT7) that make up the preamp and power tube driver circuits. This section remains pretty much intact on this board.
Tube circuit board - right
The Fromel (here) mod basically requires that you remove almost all of the capacitors, and a few resistors, from these two boards, and replace them with higher quality (in some cases, different value) parts. The trickiest part for us was not damaging the fairly delicate traces on the circuit boards while removing the old parts - soldering in the new parts was pretty easy. The other minor issue is that the replacement Switchcraft input jacks are a bit of a tight squeeze when re-mounting the boards back in the chassis. We found that filing a bit of the sandwiched insulators a tad helped prevent the jacks from contacting the circuit boards too much.
Ok, on to the cab...