Radio Road Which tuner to get and getting the most from it. Thank God, for the radio!

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RE: Ok

Posted by Neff on January 1, 2011 at 21:23:22

In Reply to: RE: Eico 2200 schematic? posted by fredtr on January 1, 2011 at 12:11:52:

Here is how to hot-rod the 2200 for more sensitivity.

Make sure the 6AQ8 is strong. Telefunken or Amperex sound great. Looking at the front of tuner, the next tube to the left is a 6AU6. Drop in a RCA 6HS6 for an increase in sensitivity and lower noise floor. Replace the next 6AU6 with RCA 6AU6. Then, drop in another RCA 6HS6 in the next position for further increase in sensitivity. The 6HS6 are expensive and the second 6HS6 adds some higher performance, but not like the first 6HS6. Finally, the last 6AU6 should be replaced with another RCA. Mullard makes the best 6AL5 in far left position. The reason I replace the Mullard 6AU6 as supplied by the factory is the RCAs sound better and are a little hotter tube.

Some will argue the next suggestion. Aligning the RF and IF sections is not too difficult with EICO built-in signal strength tube. Looking at the 6AQ8 you will see a 1/4" hole in the large can at the 10 o'clock position. Tweak that slotted slug for maximum signal. Next, tweak the next three cans. Do not touch the last can or the multiplexer card in the center of the chassis. You can replace the 6AU6 on the multiplexer with an RCA. As for the 12DW7 (7247), rare CBS are best. Next is RCA. The CBS will clear up the sonics a little.

Keep the Mullard EZ80, nothing oputperforms a Mullard EZ80. Toss the 12AU7 audio and install a Tungsram E80CC. The power transformer has no issue with higher filament current as I been using one in that position for a year.

Now, EICO 2200s had two builds. One with lousy coupling caps and another later version with the chocolate colored coupling caps. The 'chocolate' caps are good sounding and can stay in place. If you have the earlier caps, replace with AuriCap. Do not forget the caps by the stereo/mono switch. I use .22uF Auricap. At the 12AU7 I use either .22uF or .47uF AuriCap. The .47uF has slightly deeper bass response.

Finally, you will see two ceramic flat packs on the multiplexer board with three leads. These have two caps inside. You can see the series connected cap by following the traces from input to ceramic cap to the shielded cables (one per channel) on other side of cap. I use .01uF Auricap or K40Y9 Russian caps in that position. Next, the other cap is connected from the output (shielded cable) trace to ground trace. Use a 330pF mica cap in that position. The mica cap simply lowers the high frequency hiss produced by the multiplexer.

The new coupling caps & E80CC really cleans up & opens up the audio. The RCA 6AU6 & 6HS6 tubes removes that slight Mullard 6AU6 hazy sound. A CBS 12DW7 or 7247 makes the stereo ultra clean sounding like in mono or very close to it. You will hear precise cymbals, rim shots on drums, etc. The tuner will be that opened up detail wise without producing listening fatigue. Of course the rest of your system has to be of reasonably high quality.

I suspect the modded EICO 2200 sounds better than the Scott tuner.

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