Makes the pcb design easier. Once you’ve done one channel it’s just cut-and-paste for the other. It also saves the few quid on the second heater supply. If you’re not totem-poling then one of the benefits goes away anyway. But splitting between the channels does allow you to optimise the choice of triode for each stage (as with the 7044 and the ECC82).
1 Like
A 7044 won’t work in an ECC82 socket!
It can be used as a (sort of) substitute for 5687, it’s not too different from the E182CC, which can also often substitute there.
1 Like
I have a dac which fell out the back door of AN UK some time in the 90s and it has a 7044 as a common cathode as the output stage.
I rebuilt it a few years ago with new piwer supplies and a proper box.
As Pete said, 7044, 5687 and ec182cc are v v similar and can be used as subs, i like the 7044 the ones i have tried have been mechanically quieter than 5687
Security of valve supply? Does anyone do a new production 5687 or the like?
No current production on 5687, 7044 or e182cc, closest, which isnt really, is the JJ ecc99.
First batch of preamps i built mid 90s used 5687 as common cathode output, but finding quiet enough ones was a mare, too much hiss, or too microphonic, or too many “ping” noises as they warmed up. Quick change to 6111 was the solution.
I suspect practicality won out, as it did with Kondo whose preamps also moved away from 5687 to ecc82 or 6072a
2 Likes
If I recall, the first M7 valve pre used both 6072 and 5687 in both its phono & line stages.
Removed some earths. Now pretty quiet. There is hum, but that is from the power amps. Dc heaters will be appearing once I figure out how I squeeze them in safely. It will probably end up with a rewire of at least one bit and can’t be arsediness has put up a barrier to that avenue so far.
Now just need to reintroduce earths to phono stage without the hummy troll paying a visit.
Sounds really flipping good though. With no sut. Load resistors at 8-900r.
2 Likes
Spotted my boo-boo. On my psu scribble mixed chassis earth and signal ground symbols then stupidly followed it without thinking.
Sounds better than expected. Only taken me a bit over a year to do anything with them.
Had Coleman regs for the best part of 7 years iirc. Must buy transformers soon and do some sort of lash up.
2 Likes
Speaking of which - just looking at ANK and modern ANUK 4 and 5 series DACs, and that’s what they’re using paired with an ECC82 in a very similar circuit to @rmsshipbroker 2 series!
Seems Audio Note practice trickle-up technology! 
My little 1.1S uses a 6111 - if there’s crosstalk, it sure isn’t obvious…
Remembered it reverses phases so swapped cartridge tags over.
Can’t tell the difference tbh.
Will try with the sut and drop the gain a little, and take the load resistor out. Then tweak the gain up to around 60dB and see what I think.
Stupid question du jour: are Charcroft Z foil resistors likely to be susceptible to hum pickup due to there not really being anything there?
Not really.
Whereabouts are you? If you need a scope or a meter let me know.
Leamington. Have a Hantek USB scope, don’t have a huge amount of time to be able to use it.
I am in Harrold, but could figure summat out if you are struggling. Will see where I am travelling this next week or so.
How are you getting on with it?
Was looking at a smidge of hum on the new phono stage. Just moved the input cable further away from some mains and all is good.
Haven’t had a chance to do anything on it. I did the layout with the input valves right by the input so there is only a few centimetres of wire for the connection.
Need to get a scope on the heater supply when I can safely get the lid off, it is regulated by an LM338 in the offboard PSU but I am wondering whether some AC is getting through and coupling into stuff.
If you get a sec just measure the continuity of earths from power supply if it is off board.
If the dc you need to measure is a bit high then I may have a hv scope probe around somewhere. I usually put things in secret places though.
Just have contacts a good clean. Amazing what a difference it can make.
Maybe should put it in calendar.
Did some measuring with me xtz room analyser.
Did a bit of room correction with a Dspeaker anti mode too.
Confirms what is suspected. The antimode (soon to be for sale) does next to nowt in the room.
With antimode.
Without.
You should be able to tell how the system might sound from these. No need for fancy videos.
1 Like