Tubelab SSE Build For Highly Efficient Klipsch Cornwalls

[DaMuffinMan]

George, is your opinion still the same on these transformers?

"I have listened to all of these OPT's for extended periods of time with dozens of different tubes and power levels over the past year and a half. My current opinions are similar to my original statements except for the Hammond 1628SEA and the Edcor CSXE25-8-5K. My opinion was then biased against the Edcor because the measured distortion at low frequencies in UL mode(44Hz) was uncharacteristically high even at low power levels. This does not seem to translate into any audible artifacts even with large speaker systems that have no problem reproducing 44Hz. After hearing these transformers sing with 300B's VT225's and 45's (all triodes) I have learned to like them, a lot! I have cranked them up in UL with KT88's and they still sound as good as the Hammond 1628SEA, but the Hammond does have better bass".

 

[DaMuffinMan]

George...one more question... What all parts did you use to build this system. I would like to possibly build the same.

"I have another SSE that uses the larger CXSE-25-8-5K transformers playing through a home built set of speakers that use 15 inch woofers with 96db efficiency. There is NO subwoofers, but the bass from this SSE can be felt INSIDE the HOUSE ACROSS THE STREET! This SSE can produce 15 watts from 20 Hz to 18 KHz. NO SUB NEEDED, or wanted.

In this case the Electro Harmonix KT88 or 6550 tube produces the best most well controlled bass and power. I use UL mode with the CFB turned on. Pink Floyd, Depeche Mode, Metallica, all sound great at high volumes."

Thanks Dan

 

[Tubelab_com]

I used the Allied 6K7VG power transformer and the Edcor CXSE25-5K-8 which was the designation for the 8 ohm version of the CXSE25-5K. The amp used EH KT88 tubes and was run in UL mode with the Cathode Feedback turned on. All other parts were as in the manual. I removed the SS FRED diodes after some Florida lightning blew them.

My speakers were Hawthorne Silver Iris drivers mounted in 1941 vintage Zenith console radios. In UL that amp would indeed make 15 watts and those speakers were 96 db efficient, so the system got quite loud and made good bass. We never figured out why the bass was so loud inside the house across the street, yet not as loud standing in the street between the houses. I'm guessing that some of the notes, particularly most of DSOTM excited similar resonances in the identical houses.

After nearly 10 years of building amps, taking them apart, and building something else with the same parts, I would definitely choose the Edcor over the Hammond. Why, the Edcors got reused in several different amps, and currently reside in a VT225 powered TSE. The Hammonds are still sitting in their boxes on a shelf. For some reason the Edcors just sound better.

Note that both sets of transformers are now nearly 10 years old. Either or both of what you buy today may be somewhat different. I know Edcor changed their paint color right after I got mine. Very few were ever made in glowing metallic blue.

 

[DaMuffinMan]

Thanks for the reply George, hope you n your family are doing well! Love me some DSOTM!


I want to order the Edcor CXSE25 but I am not sure about the 5k 8 as I do not see that on there website is that a custom order, can someone help me.

Again my speakers are Klipsch Cornwalls from 1983, 99 db sensitivity and I believe 8 ohm.

 

[Lee from Chitown]

I believe that is a CXSE25-8-5k. Look at CXSE25 5k. You then can request 8 ohm secondary.

 

[DaMuffinMan]

Thanks for the reply Lee.

What has everyone used for the parts that have no part # on the build sheet:
Rectifier Switch
Mode Switch
Feedback Switch
Auxiliary power supply cap
Power Socket with fuse holder

Part #s or links appreciated.

---------------------------------

This is an SSE build with
Edcor CXSE25 OPT
Edcor XPWR035 or Hammond 6K7VG PT (Haven't decided which one).
Edcor XC75-2H-200mA Power Choke
Running in UL mode with
EH KT88 power tubes
12AT7 Pre amp tubes
GZ-34 or 5AR4 Rectifier Tube (no SS rectifier)

Thanks for any help or suggestions.

 

[colnago55]

On my SSE build I kept it simple and did not install the rectifier, mode or feedback switch. I set it up in UL mode with feedback. Sounds great.

Someone along the way suggested these switches:

https://www.digikey.com/product-detail/en/e-switch/100DP3T1B1M1QEH/EG2413-ND/378882

For the power switch module I've been using:

https://www.digikey.com/product-detail/en/qualtek/764-00-003/Q308-ND/417922

For a run motor cap I've been using:

Run Capacitor 100 MFD uf 370 440 v vac volts Round AC Electric Motor HVAC 100 uf | eBay

Have fun with your build

 

[DaMuffinMan]

On my SSE build I kept it simple and did not install the rectifier, mode or feedback switch. I set it up in UL mode with feedback. Sounds great.

Someone along the way suggested these switches:

https://www.digikey.com/product-detail/en/e-switch/100DP3T1B1M1QEH/EG2413-ND/378882



Have fun with your build

Thanks for the reply.

I am looking to model mine after what George posted above, "The amp used EH KT88 tubes and was run in UL mode with the Cathode Feedback turned on."

So then I don't need to purchase:
Rectifier Switch
Mode Switch
Feedback Switch

But I do need to purchase these:
Auxiliary power supply cap
Power Socket with fuse holder




Thanks Dan

 

[colnago55]

If you are not using the SS rectifier option, then you definitely don't need the rectifier switch.

You can always add the mode and feedback switches later if you want to experiment with different sounds, but they are not needed.

 

[rmyauck]

Some have said they like the GX 15W better than the CX 25W for better mid and high frequency response especially in a low power version of the amp.

Maybe there are losses in the bigger 25W design as it's a bit overkill.

 

[DaMuffinMan]

Some have said they like the GX 15W better than the CX 25W for better mid and high frequency response especially in a low power version of the amp.

Maybe there are losses in the bigger 25W design as it's a bit overkill.

Not according to George aka Mr. Tubelab "I used the Allied 6K7VG power transformer and the Edcor CXSE25-5K-8 which was the designation for the 8 ohm version of the CXSE25-5K. The amp used EH KT88 tubes and was run in UL mode with the Cathode Feedback turned on. In UL that amp would indeed make 15 watts and those speakers were 96 db efficient, so the system got quite loud and made good bass. We never figured out why the bass was so loud inside the house across the street, yet not as loud standing in the street between the houses.

I do appreciate you input!

 

[rmyauck]

I mean HF frequency which was mentioned by some on diyaudio for SSE and so so some whom could compare preferred the GX. Depends what you prefer better Bass or HF (among the differences mentioned) GX is half the price for 15W version also. If you are going for the bigger tubes and more power you are likely to want the 25W version.
I don't think George tried the GX yet?