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2 little buddy’s have just arrived! one for the plexi ecl86 and one for the 18W amp.

geoff 1965 wrote: ↑

Fri 11/26/21 8:59 am

2 little buddy’s have just arrived! one for the plexi ecl86 and one for the 18W amp.
D4E10765-4CEC-4D88-B512-F0BD8936971A.jpeg
C654CA01-0301-4DDC-88CF-7C5CB75F16D9.jpeg

Niiiiiiice!!!

Bieworm wrote: ↑

Fri 11/26/21 12:44 pm

geoff 1965 wrote: ↑

Fri 11/26/21 8:59 am

2 little buddy’s have just arrived! one for the plexi ecl86 and one for the 18W amp.
D4E10765-4CEC-4D88-B512-F0BD8936971A.jpeg
C654CA01-0301-4DDC-88CF-7C5CB75F16D9.jpeg

Niiiiiiice!!!

Those two "Made in England" G12H-30s will sound big and solid! Hardly "little buddies"

Yeah ZP!
They were in a solid state carlsbro amp that was spares/repairs,date codes are October1971 and October1972,50 years old and look at the cones they are mint,these have been looked after.

Cathode capacitor open! that’s a new sprague atom as well the little b**st**rd!
Right next fit a new one and monitor the bias voltage,those old Mullard ecl’s could be leaking internally.

geoff 1965 wrote: ↑

Thu 12/16/21 4:22 pm

D6D8E25D-70A9-4B8B-BD68-C7376E2613F0.jpeg
Cathode capacitor open! that’s a new sprague atom as well the little b**st**rd!
Right next fit a new one and monitor the bias voltage,those old Mullard ecl’s could be leaking internally.

I've got a NOS ecl86 if you're interested

update: took some time out on the amp to work on my 6V6 project and wait for a batch of toshiba 2968 mosfets I ordered to come in. Decided to remove the tag strips and build a dedicated little turret board for the amp,this started as an experiment really but has turned out to be a cool little amp and definitely a keeper! Left R9 unbypassed for now but room for a capacitor if I want the extra gain.
Filtering is now 50+50+16uf for the power & phase section and 50+30uf for the vvr & preamp,added a sag resistor to the diode rectifier side which will also drop the B+ a bit which was just over 300V on the plates.

New turret board and Toshiba SK2968 mosfet installed,looks a lot better the tag strips are good for experimenting/swapping in and out components but they look bodgey!
Back to fine tuning and finishing off this.

All safety checks done,one tweak to the B+ to preamp replaced the 8K2 dropper with a 6K2 and test voltages are now
V1 pins1&6: 133
V2 pin6: 273. pin1:153
Phase plates: 193&192
Pentodes plate pin6: 288 Screen pin3: 265 Cathode pin7: 9.03
B+ at first cap 306
The cathode voltage on the pentodes is dead stable so that’s a good sign also no DC on the pots.
The 100ohm sag resistor has brought the diode rectified voltages down to virtually the same as tube rectified.
Time to take the dummy load out and plug a G12H 30 in! Just want to experiment with R9 now.
Also the VVR is working perfectly now,very smooth with no crazy fluctuations!

Spoke a bit too soon regarding the VVR! all the test were good under a dummy load,nice smooth drop and increase in voltage when sweeping “but” with the speaker in i’m getting a lot of noise.it’s fine on full or minimum vvr but the noise starts when increasing or decreasing.
The amp is dead quite with no hum and all the lead dress is good,the passive series effects loop is also very good with no noise or oscillations.
Back to the drawing board!
Afterthought I don’t have a spare set of ecl’s at the moment to swap in so not sure if it’s them?

Okay replaced the ecl86 sockets and this time was very careful not to put too much heat on the lugs,also picked up a nice pair of mullard NOS ecl86’s on eBay so hopefully now the noise issue when sweeping the vvr will be cured,if not it’s baffled me!

Hey Geoff.. what exactly draws you to the ECL86 tubes? How do they differ from EL84 sonically?
The 6AQ5 tubes Dayn uses in those filmosound amps intrigue me too.. they're supposed to be smaller bottle 6V6 alike...

Mainly the secondary HT of the power transformer Bieworm,it’s 250-0-250 so suited to the lower plate voltages of the ecl86’s,the hi-fi amp it came from was running 4 ecl82’s.can’t give you a true comparison yet till I nail this noise issue but ZP’s description of his ecl86 lite 2 was also an inspiration.

geoff 1965 wrote: ↑

Mon 05/30/22 12:58 pm

Mainly the secondary HT of the power transformer Bieworm,it’s 250-0-250 so suited to the lower plate voltages of the ecl86’s,the hi-fi amp it came from was running 4 ecl82’s.can’t give you a true comparison yet till I nail this noise issue but ZP’s description of his ecl86 lite 2 was also an inspiration.

Hope you'll get rid of the noise this time. It can be quite frustrating... I'm looking forward to hearing the raggedy little weasel

To my ears at least, the ECL 86-based "13W Lite II has a creamier overdrive tone than a regular EL84-based 18W