S.E.X. Ehnancement

[hirez69]

After one year of wonderful listening with my S.E.X. amplifier (Full Magnequest Nickel iron supplement and C4S, DACT pot) I would ask if there are other changes to further improvement of the sound.
I ask you to suggest  everything that in your experience has proved successful:

Components replacement,
tubes (Tung Sol?), capacitor (Mundorf Silver Oil?), resistor (499R?) replacement.....

Thanks

 

[Grainger49]

I'm a capacitor junkie.  So...

The Parafeed capacitor could be replaced with a better capacitor.  I have suggested Obbligato 2.2uF@630V to several posters who were happy with them but the value changes when you upgrade the iron, I think.  You might want to check into what value you need.  But remember, capacitors are a flavoring, each sounds a little different and they must appeal to your taste.  There are a lot to choose from.  This is the biggest improvement.

This is a post comparing the cost (only) of capacitors that could be used in a Seduction or FP 2.  It will give you names of manufacturers and some sources:

Old Capacitor Comparison

The second largest bang for the buck is in modifying the power supply capacitors.  The B+ capacitor (47uF@450V) could be replaced with a better capacitor (Obbligato Film/Oil) or just bypassed with a much better capacitor (KK Teflon).  The bypassing is easy, quick and can be done with jumper clips for comparison.  But remember there are some really dangerous voltages there ! ! !  

The "Rpsu" could be replaced with a choke, I don't have suggestions.  

Then last the interstage coupling capacitor (0.1uF@630V) can be replaced with a better capacitor.  This makes some difference but a bit less than the other suggestions.

Hope this helps.

 

[tsingle999]

V-cap 0.1 coupling cap. I have a 1uf Mundorf parafeed cap in now but I would like to try some higher values to see if I can get a bit more bass out of the amp.
If you want to have some fun with large caps you can replace the 22uf and 47 uf with large obbligatto power supply caps.
I prefer the non-RCA coin based tubes....

 

[dmannnnn]

I have stated before that I believe a 'ladder style' attenuator with good resistors sounds more transparent than the DACT, especially at lower volume levels.  If the DACT is wired as a standard series attenuator, there will be up to 23 resistors in the signal path along with all the solder joints (I also have a completely unfounded bias against surface mount resistors).  The ladder style has only 2 resistors no matter what level it is set at.  Here is the thread:

http://www.bottlehead.com/smf/index.php/topic,94.0.html

At your most used listening levels you can use 'Super-Duper-Top-of-the-Line' resistors.  You will only need 2 for each position you want to upgrade.

I have a 1uf Mundorf parafeed cap in now but I would like to try some higher values to see if I can get a bit more bass out of the amp.
....

I got better bass response out of my amp by wiring it for 4 ohms.  Though, it probably depends on your speakers .

 

[BNAL]

I use Russian Teflons for coupling and film in oil Obbligatos for parafeed and have been very happy with the performance. I will have to look at the caps on the B+. Sounds like that would make a nice tweek. Also, sounds like from the Quickie forum that chokes maybe even better.

 

[audiblesoundwave]

Hi,

Does this 'ladder style' attenuator wire as way as stated in the manual?

Thanks,
Milton