mwhouston Posted May 16, 2019 Share Posted May 16, 2019 7 minutes ago, A J said: I would be keen to have a look ? What tubes does it use ? AJ Any tubes any schematic. Here 12AT7 and 6L6 but use any schematic you like. Link to comment Share on other sites More sharing options...
A J Posted May 16, 2019 Share Posted May 16, 2019 6DJ8 and 6L6? That could work for me 1 Link to comment Share on other sites More sharing options...
mwhouston Posted May 16, 2019 Share Posted May 16, 2019 1 minute ago, A J said: 6DJ8 and 6L6? That could work for me Can you post the schematic orPM it to me. Sound good. Link to comment Share on other sites More sharing options...
betocool Posted May 16, 2019 Share Posted May 16, 2019 Just curious, where do you guys get your tubes? Cheers, Alberto Link to comment Share on other sites More sharing options...
mwhouston Posted May 16, 2019 Share Posted May 16, 2019 40 minutes ago, betocool said: Just curious, where do you guys get your tubes? Cheers, Alberto Mainly just troll the internet. eBay quite often. Link to comment Share on other sites More sharing options...
betocool Posted May 17, 2019 Share Posted May 17, 2019 Quality ok? Are they new or old? I'm asking because of ignorance, that's all. Cheers, Alberto Link to comment Share on other sites More sharing options...
mwhouston Posted May 17, 2019 Share Posted May 17, 2019 NOS is good but lately new either direct from Psvane or through eBay. Go for new that way you should feel confident of good operation. On another note I’m with Telstra mail - outlook - and I am not getting any mail at all. Are other having the problem. Link to comment Share on other sites More sharing options...
eman Posted May 17, 2019 Share Posted May 17, 2019 9 hours ago, betocool said: Quality ok? Are they new or old? I'm asking because of ignorance, that's all. Cheers, Alberto Psvane are a good place to start for current production bang for buck. Shuguang have a premium line too. Find them ebay or elsewhere online. 1 Link to comment Share on other sites More sharing options...
mwhouston Posted May 18, 2019 Share Posted May 18, 2019 ShuGuang and Psvane is what I would also recommend. 1 Link to comment Share on other sites More sharing options...
mwhouston Posted May 19, 2019 Share Posted May 19, 2019 To checkout the tube front end I rough wired the preamp section to the output and had it drive a small tube amp. It worked perfectly. Now I know the front end is working correctly and all voltages are as they should be I can build the OPAMP section now for this hybrid headphone amp. Link to comment Share on other sites More sharing options...
mwhouston Posted May 19, 2019 Share Posted May 19, 2019 The tube I’m using in this is ones I have had around for years. Tung Sol 12AX7 gold pin. Really just trying to use up my excess tubes. Link to comment Share on other sites More sharing options...
F18 Posted May 19, 2019 Share Posted May 19, 2019 Halfway restoring an avo vcm mk4. New painted side supports, cleaned knobs and switch holders, faceplate touched up and painted with couple coats of clear 2x, new replacement meter (expensive) installed. Still need to disassemble and clean roller switch, measure and test internal resistors and calibrate if necessary. 3 Link to comment Share on other sites More sharing options...
Janus77 Posted May 20, 2019 Share Posted May 20, 2019 First DIY project, very basic. Thanks Raiden for the advice on building. Stands for the Paradigm 9se, they still need sanding, painting and speaker spikes installed (awaiting delivery). Very solid stands, using some Lego to bring them up to the intended height until the spikes arrive. Satisfying building something, lucky I have a relative with a table saw and clamps. 1 Link to comment Share on other sites More sharing options...
aussievintage Posted May 20, 2019 Share Posted May 20, 2019 17 hours ago, F18 said: Halfway restoring an avo vcm mk4. New painted side supports, cleaned knobs and switch holders, faceplate touched up and painted with couple coats of clear 2x, new replacement meter (expensive) installed. Still need to disassemble and clean roller switch, measure and test internal resistors and calibrate if necessary. What a lovely looking machine. That certainly was a different era in electronics. 2 Link to comment Share on other sites More sharing options...
aussievintage Posted May 20, 2019 Share Posted May 20, 2019 On 16/05/2019 at 12:30 PM, mwhouston said: The tranni box box is two 12V 300VA Trannies back to back to produce 250VAC and 12VAC for the two 6V filaments (in series). Damn, I thought I was the only one who used that method. 1 Link to comment Share on other sites More sharing options...
mwhouston Posted May 20, 2019 Share Posted May 20, 2019 46 minutes ago, aussievintage said: Damn, I thought I was the only one who used that method. I’ve used it dozens of time of a small and large scale. My tube preamps run from a 24V 1A AC wall wart that backs into the secondary of a small 24V step down Tranni to give me ~250V. Link to comment Share on other sites More sharing options...
aussievintage Posted May 20, 2019 Share Posted May 20, 2019 36 minutes ago, mwhouston said: I’ve used it dozens of time of a small and large scale. My tube preamps run from a 24V 1A AC wall wart that backs into the secondary of a small 24V step down Tranni to give me ~250V. I use a 12Vac wall wart, but, same. Much easier to get than a 'proper' valve power transformer. Link to comment Share on other sites More sharing options...
F18 Posted May 20, 2019 Share Posted May 20, 2019 6 hours ago, aussievintage said: What a lovely looking machine. That certainly was a different era in electronics. Sure is and 50 years later it is still one of the best tube testers around. Link to comment Share on other sites More sharing options...
mwhouston Posted May 22, 2019 Share Posted May 22, 2019 (edited) Can anyone see what I have done wrong here TWICE! All values are correct but here is a hint - look at the red wire which connects the positive voltage. Only three guesses gents. Edited May 22, 2019 by mwhouston Link to comment Share on other sites More sharing options...
mwhouston Posted May 23, 2019 Share Posted May 23, 2019 (edited) The hybrid headphone amp (LeManja) is completed and sounding good. Still trialling the limiting resistor for the reg but all else checks out. With a universal front end any 12A?7 can be installed with no adjustments to bias etc. The backend is driven by a PT2308 - a dedicated headphone very low distortion driver chip (Class A/B). The chip runs on 7V max so I’ve used a 6V reg. About to have a be a big listen. Current tube is a new Ting Sol gold pin. After seven hours on the end of this new HP amp I am extremely impressed. So very pleased. It will go up for sale. PM if interested. Edited May 23, 2019 by mwhouston Link to comment Share on other sites More sharing options...
A J Posted May 23, 2019 Share Posted May 23, 2019 I think I want this t-shirt - in fact I’ve ordered one. My wife won’t get it - in fact I can only think of 1 friend who actually would haha 2 Link to comment Share on other sites More sharing options...
betocool Posted May 23, 2019 Share Posted May 23, 2019 7 hours ago, mwhouston said: Can anyone see what I have done wrong here TWICE! All values are correct but here is a hint - look at the red wire which connects the positive voltage. Only three guesses gents. Isn't V+ supposed to be 4? Cheers, Alberto 1 Link to comment Share on other sites More sharing options...
mwhouston Posted May 23, 2019 Share Posted May 23, 2019 1 minute ago, betocool said: Isn't V+ supposed to be 4? Cheers, Alberto No 8 is V+. But you are in the right track. Link to comment Share on other sites More sharing options...
Pops110 Posted May 23, 2019 Share Posted May 23, 2019 31 minutes ago, A J said: I think I want this t-shirt - in fact I’ve ordered one. My wife won’t get it - in fact I can only think of 1 friend who actually would haha Where’d you order that from mate? Link to comment Share on other sites More sharing options...
Guest Muon N' Posted May 23, 2019 Share Posted May 23, 2019 I'm just a lowly part swapper so not really building. Installed some better caps on the out put of my old bog standard CD65, an easy improvement. Removed the remote and Digital board to utilise the rca holes to mount some ETI sockets. Might get me back into listening again. Link to comment Share on other sites More sharing options...
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