Up for sale is a highly upgraded and very popular Fisher X-202-B integrated amp. This is not your usually upgrade as many do but upgraded to a very high level and sounds so very good.
See the very long list of upgrades below from the person who did the upgrades.
Please don't ask about trades, lower price, or if it's available because as long as the AD is up it is available.
If interested please send me your name and contact number and I will be happy to contact you.
Following in the footsteps of previous efforts with my 400 receiver, an X-1000 and X-101C, this time it's an X-202B being presented for modernization. However, unlike those projects, this one also includes a full electrical refurbishment, with the thread being offered then simply as a record for referral for those with their own 202B projects.
First up is the laundry list of items addressed, to give some perspective to the work presented in the pics. Those items include:
1. A complete recap of all power supply and audio circuits.
2. Installation of an appropriate AC line current limiter.
3. Installation of cathode sampling and screen stability resistors in the output stage.
4. Installation of test points to allow adjustment of DC bias and balance controls without removal of the bottom cover.
5. Convert the output stages to operate with the speaker common leads referencing ground level.
6. Install EFB for improved output stage performance and extended tube life.
7. Improve phase inverter performance by removal of the inverter "noose".
8. Convert the old Reverb In/Out jacks to new Preamp Output/Power Amp Input jacks.
9. Remove the Aux 2/Tape Monitor Bleed circuits.
10. Remove the two permanent LF filters from the original design. The switchable Low and High Frequency filters remain.
11. Fix any other issues noted along the way.
These are all modifications made to the previous units mentioned, but installing them is never the same in any two models, so it's always a slow go on the first go round. Mix the holidays in there, and its been a solid two month project. Some of the modifications are rather easy, while others are quite involved.
The one section of this unit that was not being addressed was the phono preamps. They had previously been recapped, and were otherwise not the priority of this unit. Therefore, they were addressed only in terms of operational needs.
This unit was initially in rough shape. Missing its bottom cover, it did work after a fashion, but had very poor previous repair work done to it, and needed a lot of TLC: Most of the indicator lamps were bad, the Mode Switch was frozen, the chassis service controls all had a "grind" to them when rotated, the grommets for the phono preamp tube sockets had all but rotted away, and the preamps themselves didn't work. Plus, the thing was just filthy. Still, an initial evaluation indicated that the basic goods were in tact, which allowed the project to move forward. Tubes were performance checked, replacements obtained as needed, and work began.
At this point, the pics present the finished work, with a battery of listening and lab tests on tap later this week.
It will probably take two or three posts to present the pics, with a brief explanation of each provided.
1. The HV power supply area. The 202B has a busy underside to begin with, and with the modifications made, things got a whole lot busier. In this pic:
A. The hi side doubler can has been replace, and the old cardboard protector removed from the old cap, and installed on the new.
B. New Ultra Fast HV diodes now replace the old ones.
C. The low side doubler can has been replaced with discrete caps which have been mounted in place with silicone.
D. Since this unit had already had the Control Plug internally jumpered, that was just taken one step further, and all the wiring to the Control Plug removed. This freed up space, and allows the Control plug to now perform test point duty, making that feature completely non-evasive.
E. In the middle of the power supply area is the EFB Screen Grid Regulator circuits, and good eyes will spot the power Mosfet associated with this circuit near where the AC line enters the unit.
F. A CL-80 rounds out the power supply modifications. This device provides for safe turn on, while still allowing full power output to be developed.
2. The Low Voltage DC Heater/Bias supply area. Here the original can cap was retained, since there is no known replacement for it. Discrete caps now do the work, along with an upgraded dropping resistor as well (10 watts versus 7 watts). Also two small circuit boards can be seen which will be detailed in other pics. Note also the recapping of the tone control amplifier stage. I do not use the snip and tac method of component replacement, as part of what makes a Fisher a Fisher was the original build quality, which I make every effort to leave in tact.
3. The EFB Control Grid Regulator is built on a board that is mounted to the line stage shield box. It works in conjunction with the original adjustment controls, so that the process of setting the bias and balance remains unchanged, except for the quiescent current level target itself.
4. In converting the output connections so that the Common output terminal operates at ground level, it requires the removal of the wiring to the center speaker level control switch (earlier models had a line level volume control in this position), the speaker on/off switch, the off position load resistors, and the headphone jack wiring as well. Since I was in there, the channel identity of the headphone jack was also corrected. On the left, the caps on the loudness switch were replaced as well, and strangely, this unit seems to have been built without an AC switch cover. Since there is no longer a Center Channel Speaker output, the Center Channel indicator lamp now stays at full brightness all the time now.
5. The output stage has had individual cathode current sensing resistors and screen stability resistors installed, with the old cathode resistors removed. Additionally however, all of the OPT wiring was removed, leads extended as required, and reinstalled/reconfigured to finish the Common output terminal modification. This modification causes the unit to reverse absolute phase now, but is a small price to pay for having the inputs and outputs now all reference ground. This can easily be resolved by reversing the speaker leads if that is of concern. Also note on the back panel the absence of the components making up the bleed circuits between Aux2 and the Tape Monitor settings.