![]() are out there, we source ours from reputable whole-sellers and buy it in bulk. Knowing how many bogus/fake caps, diodes, resistors etc. We are extremely particular about the quality of the parts provided with this kit. It comes with high quality capacitors that have 5,000-12,000 working hrs life expectancy. All the parts are of high quality authentic Nichicon / Rubycon / IC / United ChemiCon capacitors. The restoration kit will make a huge difference in sound quality. So far I have replaced all electrolytic capacitors and any tubes that are marginal or have failed. Knowing how amazing and warm these units can sound, we decided to develop this kit. I am restoring my fathers Heathkit SA-2 14Watt Amplifier. A complete dual channel amplifier/preamplifier combination, the new Heathkit SA-2, in one compact, handsomely styled unit provides every modern feature required. We have seen many bad quality restorations/fix jobs done to these units that made them sound cheap and very low quality. Buy-Now Price: 270 Reference Price: Brand/Model: Heathkit Heathkit Market: Reverb Post navigation. It can sound amazing if properly restored. Heathkit SA-2 SA-2 Vintage Tube Amplifier Amp. We have been servicing audio equipment for many years and have developed deep respect toward good vintage audio equipment. This kit offers parts and instructions for a full/complete restoration. Heathkit sa 2 how to#Instructions on how to clean the chassis, faceplate, knobs Heathkit sa 2 manuals#Now, multiply that by 2 for Stereo (well, only one bias supply).High quality, authentic electrolytic and film capsĭetailed instruction with colorful images, schematics, manuals (all of these are in electronic form (can be printed), much better than printed versions due to zoom availability)ĭiodes, bridge rectifier, thermistor, lamps (if shown in the picture) Can anyone tell me what sound characteristics should I expect from this amp Also, any info regarding Heathkit is appreciated. Will hook a pair of PSB B-25 speakers to it. Heathkit sa 2 full#Multiply the potentiometers by 2 for Stereo. Heathkit Integrated Amp SA-2 Hide sidebar Guangui G Guangui Full Audioholic 1 I just got a vintage Heathkit SA-2 as a gift. Just like so many things, it is a tradeoff.įixed adjustable bias for a pair of push pull tubes: I went one step further and checked all power supply and tube voltages against the. The amp passes the rudimentary initial test in the back of the manual. A weird little kit with some interesting technical features, but relatively mediocre overall performance. ![]() Heathkit sa 2 manual#That means the (fixed adjustable) manual bias robs from the range of the self bias circuit (less auto adjustment effect).Ī self bias resistor that gives all of the bias has a good self adjustment range (no fixed bias circuit).Ī self bias resistor that gives only 1/2 of the bias voltage, only has 1/2 of the self bias auto range (1/2 of the bias in the fixed bias circuit). I am restoring my fathers Heathkit SA-2 14Watt Amplifier. Global negative feedback can not fix some of the errors in the design and implementation of an amplifier, and this is one of them it can not fix.Ĭombination bias gives both some auto adjustment range, and some (adjustable fixed) manual bias adjustment range of the current.īut the amount of auto adjustment due to the self bias resistor is proportional to the ratio of the resistance of the self bias resistor, versus the impedance of the cathode. It shows the increased distortion at 20Hz and even at 100 Hz, when there is just a small un-balancing of the push and pull quiescent DC currents.Īnd, that graph was taken With the global negative feedback. If you have any doubts about the extra distortion caused by un-balanced DC currents, look up the very last 2 pages of the Heathkit W5 amplifier manual. In regards to power at 20Hz, nothing will ruin the distortion faster than unbalanced DC in the push and pull windings. 1dB less power of 13.69 Watts is so much quieter.ġ dB difference of continuous power will not make any difference, both will burn out 95% of all tweeters. If you need 17.22 Watts at 20kHz going to your Tweeter, then you need to use fixed bias for that pair of EL84 /6BQ5. Those large bias voltages do rob lots of B+ voltage when you use self bias, and that robs output power. It is not a large Beam Power tube, or a large Pentode, they require 30, 40, or 50V of bias. This amp works but has a low level hum which is stable and a static which is volume dependent. First of all, the bias voltage for EL84 / 6BQ5 is only a few volts. Here is a Heathkit SA-2 EL84 PP tube integrated amp. ![]()
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