SimpleSE - Reborn...again

[cjkpkg]

I have been busy building over the past two years different types of amps - tube, chipamp, SS etc...The SimpleSE was my first DIY build and in its original form used the cheap edcor XSE OPTs. I quickly updgraded those to James 6123s and listened for a while and the SimpleSE went out of rotation for a while.

I recently built my first DHT SE amp - 300Bs and scavenged the James OPTs for this due to the mulitple taps and ordered a set of Edcor CXSE 5K 4ohm units. They took the usual 6 weeks and arrived last week finally.

I ordered a new top plate rearranged the layout and did the final assembly tonight. I took the opportunity to upgrade the binding posts and redo the input wiring. Still using SS rectification as my spare 5AR4 is pulling duty in the 300b.

This mother is HEAVY - must be at least 40lbs. B+ is a solid 450 and after trying out a couple different inexpensive coupling caps switched back to the orange drops - I still want to try some others out though...maybe some PIO either new or NOS Russian ones.

One word...BASS! holy cow I would say that the difference even from the cheap XSE's to the James was not as dramatic as the James to these giant CXSE's. They are truly amazing!!! This is like having a totally new amp...

[rknize]

Indeed, SSE + KT88 + CXSE5K* = awesome bass.

[tubelab.com]

You probably don't want to hear this, but......I borrowed the CXSE's from my SSE and wired them to my TSE 300B and they never went back. The bass is not as solid as the SSE with KT88's, but 300B's can ROCK!

[tomchr]

Yep. TSE-inspired design with CXSE25-8-5K, JJ 300B, 370 V, 60~65 mA --> very nice!

~Tom

[rknize]

I have One Electron UBT-2s on my TSE. They are also quite large, though not as big as the CXSE's. They also rock pretty good with my more sensitive speakers and 300Bs, but I always find myself going to back to 45s on that amp.

[cjkpkg]

I did try them out in the 300b before I cut any metal and actually I prefer the James in the 300b to my surprize. When I switched the James back in I hooked up the 2.5K tap and I must say I am really pleased. Its a standard 6sn7 front end very similar to the JE Labs one. I did try Powerdrive in it but could not get the 300bs to bias up...Used the values from the TSE schematic for the setup and IRFBC30's...that one really stumped me...

Of course now I am temped to get another set of Edcor's with a lower value than the 5K...

[cjkpkg]

Update...

I took the 300b down for service and wanted the SimpleSE back on duty. With the bias cranked up to ~100mA per KT88 the 6K7VG was getting VERY hot...

A while back I ordered an edcor XPWR033 760V 200mA with 5V and 6.3V windings. Tonight I yanked out the allied and put in the edcor and WOW...very happy with the results.

JJ GZ34
Mullard CV4024
Gold Lion reissue KT88

B+ now nets out at 426V
Cathode L = 37.2V 119mA
Cathode R = 38V 122mA

Right now each cathode is running a 560R and 700R in parallel for 311R net. I think maybe I will back it down to ~400R to keep the tubes healthy. I ought to put a switch in someday to be able to switch back between the KT88s and EL34s etc...

The xpwr033 is running much cooler than the 6K7VG was and the bass just seems maybe a little better now.

[tubelab.com]

100mA per KT88 the 6K7VG was getting VERY hot...

I'm surprised that the paint hasn't peeled off of mine and its still alive. It smells funny after running for a few hours at a time. I am using a 1K in parallel with the 560 ohm on the board. I put alligator clips on the 1K's and I clip them on when using the KT88's.