Whaleman
Hi-Fi Rescue Mission
Learned a lot from the folks here with the First Mishap of the HH Scott 299-D, so armed with that information, I took a minimalistic approach to recapping the Stereomaster 233 (basically the same amplifier but 7 watts less per channel (33 watts)) for safe use.
This thread has a good outcome from the start, so no cliff hanger or such, this information learned from the other thread was valuable:
1. High voltgage = potential death, one hand in back pocket
2. Do not run the amp with no speaker load
3. Make sure the tubes are good, here I am using all Russian Electro Harmonix EH in the rear and all Chinese (Vibrant B) in the front except for the phase spliters, they are the Telefunken. The sound is nice and detailed, the bass very strong. No harshness at all at the top. Sounds better than the old stock config in my opinion.
4. The HH Scott headphones are wired in reverse
5. Do NOT overtorque any screw is this amp. Use only finger torque, using your wrist will strip the thread
I started by ordering all the electrolytics from www.tubesandmore.com. I also could not find a 100 uF x4 @ 75 VDC can, so I decided to get 4 100 uF @ 100 VDC high temperature caps from www.mouser.com. I also got some terminal blocks from Radio Shack to hold these down. Went to Home Depot and got matching metal screws to the Scott for holding these down. With excess wire from the deleted multisection can, I soldered any necessary new grounds.
Things went without a problem and the amp has about 20 hours after biasing and balance and sounds absolutely the best of anything I own. Quite a reward for minimal work invested. The parts excluding tubes and misc. were just around $125. To top things off, I installed a new set of McIntosh feet for the Hot Rod look and better cooling, also the proper screws (#6 I think) were used for the Mac feet. Took about 16 hours total.
Here is the amp before surgery:
Here are the new parts and old resistors. I used a 40 uF x 3 @ 525 VDC for the power supply. The first section is split for the output transformers B+.
It drives a pair of Cerwin Vega E-712 to magnificent audio nirvana.
This thread has a good outcome from the start, so no cliff hanger or such, this information learned from the other thread was valuable:
1. High voltgage = potential death, one hand in back pocket
2. Do not run the amp with no speaker load
3. Make sure the tubes are good, here I am using all Russian Electro Harmonix EH in the rear and all Chinese (Vibrant B) in the front except for the phase spliters, they are the Telefunken. The sound is nice and detailed, the bass very strong. No harshness at all at the top. Sounds better than the old stock config in my opinion.
4. The HH Scott headphones are wired in reverse
5. Do NOT overtorque any screw is this amp. Use only finger torque, using your wrist will strip the thread
I started by ordering all the electrolytics from www.tubesandmore.com. I also could not find a 100 uF x4 @ 75 VDC can, so I decided to get 4 100 uF @ 100 VDC high temperature caps from www.mouser.com. I also got some terminal blocks from Radio Shack to hold these down. Went to Home Depot and got matching metal screws to the Scott for holding these down. With excess wire from the deleted multisection can, I soldered any necessary new grounds.
Things went without a problem and the amp has about 20 hours after biasing and balance and sounds absolutely the best of anything I own. Quite a reward for minimal work invested. The parts excluding tubes and misc. were just around $125. To top things off, I installed a new set of McIntosh feet for the Hot Rod look and better cooling, also the proper screws (#6 I think) were used for the Mac feet. Took about 16 hours total.
Here is the amp before surgery:
Here are the new parts and old resistors. I used a 40 uF x 3 @ 525 VDC for the power supply. The first section is split for the output transformers B+.
It drives a pair of Cerwin Vega E-712 to magnificent audio nirvana.
