An Exercise in Daftness.

A place for DIY project discussions.
Forum rules
1. No ad-hominem
2. No spamming or shilling
SteveTheShadow
Posts: 1042
Joined: Thu Sep 12, 2013 5:24 pm
Location: S Yorks
Great Britain

Re: An Exercise in Daftness.

Unread post by SteveTheShadow » Sat Nov 24, 2018 6:23 pm

:mrgreen:

Well we have heaters now:
Image

It's been a while since I last saw these beauties all lit up

27V when powered up, so not far off the 26V spec.

The far valve is nowhere near as bright as it looks on the pic. They are both the same, dull red, so not a problem.
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

SteveTheShadow
Posts: 1042
Joined: Thu Sep 12, 2013 5:24 pm
Location: S Yorks
Great Britain

Re: An Exercise in Daftness.

Unread post by SteveTheShadow » Sat Nov 24, 2018 8:33 pm

Just cooking the second pair of valves:
Image
These are the oldest pair; from the late 1950s, I think. They don't have the extra cooling fins on their anodes, so I will be using the newer ones above in the OTL. Given that the tubes will be running nearly 80W dissipation each, I don't want to thrash unnecessarily, the older ones.
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

SteveTheShadow
Posts: 1042
Joined: Thu Sep 12, 2013 5:24 pm
Location: S Yorks
Great Britain

Re: An Exercise in Daftness.

Unread post by SteveTheShadow » Sun Dec 02, 2018 11:16 am

A lot of mechanical work has been done, caused by me changing the layout because I wasn't happy with it.
99% of the bits have been attached to the board and heaters are now live on both the 5687s (small valves) and the 13E1s:
Image
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

SteveTheShadow
Posts: 1042
Joined: Thu Sep 12, 2013 5:24 pm
Location: S Yorks
Great Britain

Re: An Exercise in Daftness.

Unread post by SteveTheShadow » Sun Dec 02, 2018 11:20 am

Cap-choke-cap power supply for the output stage can be seen to the left of the big output valves and uses 2200uF, 200V panasonic caps.
Large JJ, 100 + 100uF cap (right) is the final cap-resistor-cap section of the 300V supply, which will be derived from a voltage doubler. This will feed the small input stage, twin-triode valves.
Image

AC for the heaters reads 26.8V (should be 26) per 13E1 and 12.3V (should be 12.6) for the input stage/drivers.
That'll do for me.

Three pin TL783 regs on box-section aluminium heatsinks will form constant current sinks for the output valves, locking them to half an amp to prevent runaway, and overheating.
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

SteveTheShadow
Posts: 1042
Joined: Thu Sep 12, 2013 5:24 pm
Location: S Yorks
Great Britain

Re: An Exercise in Daftness.

Unread post by SteveTheShadow » Sun Dec 02, 2018 7:38 pm

Output stage PSU and the Septar valve bases are wired up apart from the cathode constant current sinks.
Image

Off load DC voltage is a healthy 168V...ish.
No music from it this weekend unfortunately.
Input stage voltage doubler power supply is next.
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

User avatar
Dr Bunsen Honeydew
Posts: 29694
Joined: Wed Jul 11, 2012 7:26 pm
Location: Muppet Labs
Great Britain

Re: An Exercise in Daftness.

Unread post by Dr Bunsen Honeydew » Sun Dec 02, 2018 7:48 pm

The traditional Audio Talk bodge (joke) you have to use a sheet of ply. Will you leave it as a classic DIY or transfer it to a chassis.

SteveTheShadow
Posts: 1042
Joined: Thu Sep 12, 2013 5:24 pm
Location: S Yorks
Great Britain

Re: An Exercise in Daftness.

Unread post by SteveTheShadow » Sun Dec 02, 2018 8:32 pm

Dr Bunsen Honeydew wrote:
Sun Dec 02, 2018 7:48 pm
The traditional Audio Talk bodge (joke) you have to use a sheet of ply. Will you leave it as a classic DIY or transfer it to a chassis.
If it works, then it'll be transferred to a proper chassis........eventually.....maybe. But it's really going to have to be absolutely outstanding to qualify for chassisdom. :) The, potential, I think, is there for something special.
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

SteveTheShadow
Posts: 1042
Joined: Thu Sep 12, 2013 5:24 pm
Location: S Yorks
Great Britain

Re: An Exercise in Daftness.

Unread post by SteveTheShadow » Sun Dec 02, 2018 10:14 pm

Couldn't stop at the one power supply, so now we have the full complement of two:
Image

Full wave voltage doubler supply for the input/driver stage is now live and uses high voltage Schottky SiC diodes.

357V off-load, so I'm pleased with that. Should give plenty of swing from the driver stage.
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

setting son
Posts: 47
Joined: Mon Aug 25, 2014 2:51 pm
Great Britain

Re: An Exercise in Daftness.

Unread post by setting son » Tue Dec 04, 2018 7:28 pm

Nice, Steve. Bonkers, but nice.

SteveTheShadow
Posts: 1042
Joined: Thu Sep 12, 2013 5:24 pm
Location: S Yorks
Great Britain

Re: An Exercise in Daftness.

Unread post by SteveTheShadow » Wed Dec 05, 2018 12:49 am

Bonkers indeed!
Complete bloody madness if you ask me!
Nothing's caught fire yet. It seems stable and runs sweet as a nut.

Image

A top class music maker, though I say so myself. :mrgreen:
Well pleased with it after sorting out the driver stage power supply, which sounded like a wasp in a coke can
until I sussed what was up with it.
DIY NVA amplification ( roughly equivalent to NVA A60) BTE Designs passive preamp, BTE Designs Lenco L75 turntable, Rega R200 arm, Goldring E3 cartridge, NVA Phono 1
Musical Fidelity M1 DAC, AppleTV4 with Apple Music subscription, ripped CDs streamed via WD MyCloud Home Duo NAS, with PLEX media server.
Speakers - Large sealed cabs, with Fane 12-250-TC 12" full range drivers.

Post Reply