Hi Thomas
thanks for the explanation. We know us and so I will trust you here. Regarding the Autoformer, why not using the secondary of the output transformer as volume control - you can save an iron?
Are you still using your DHT phono stage?
Kind regards
Joao
Hi!
Thomas
Sure that would be the logical choice. Unfortuntaley no such transformers available which would suit my circuits. I'm still trying to convince Lundahl to make something like that
Not in the moment. I plan to rebuld it next year after some of the cirrent projects are finished
Thomas
Hi João and Thomas,
Pieter_T, a member of diyaudio and owner of Tribute Audio once wrote he made a line stage output transformer with tapped secondaries for volume. That unit was SE, but surely he can also make something PP. I just did not insist as Tribute Audio is very fine stuff indeed, but pricewise out of my league.
Good to hear a good Lundahl customer is pushing Lundahl into making something similar. A LL1660 with tapped secondaries would be very nice, and still fit my budget. (Even though, all the additonional tapping and terminating will result in lots of extra work, and therefore the 'LL1660 18mA volume control' may end up costing more than a standard LL1660.)
best regards, Erik
Pieter_T, a member of diyaudio and owner of Tribute Audio once wrote he made a line stage output transformer with tapped secondaries for volume. That unit was SE, but surely he can also make something PP. I just did not insist as Tribute Audio is very fine stuff indeed, but pricewise out of my league.
Good to hear a good Lundahl customer is pushing Lundahl into making something similar. A LL1660 with tapped secondaries would be very nice, and still fit my budget. (Even though, all the additonional tapping and terminating will result in lots of extra work, and therefore the 'LL1660 18mA volume control' may end up costing more than a standard LL1660.)
best regards, Erik
Yes this is a step foreward, hope you will find the sweet words you need to convince Lundahl
QUOTE=Vinylsavor;2797702]
Not in the moment. I plan to rebuld it next year after some of the cirrent projects are finished
[/QUOTE]
Your quiet very busy .... hope I will finish my work as well untill 1st quarter of next year.
@ErikdeBEst: Thanks for the hint, I did use Pieters stuff already, not the TVCs though. I emailed him about such a transformer.
Best regards
Thomas
I did manage to convince Lundahl to make the filament chokes, a suitable output transformer for the 10Y/801A and also the newly released plate choke on a larger core than LL1667/8. But he is not catching onto the idea of a volume control (yet)...
Best regards
Thomas
Hi Thomas
do I recall correct that you prefer the Lundahls over Pieter's transformers? Did you make comparisons with transformers from Dave Slagle?
Thanks and kind regards
Joao
Hi!
This is leading too far off topic here. Let's not hijack this thread.
No I never stated anywhere that I prefer Lundahls over Pieters.
Thomas
This is leading too far off topic here. Let's not hijack this thread.
No I never stated anywhere that I prefer Lundahls over Pieters.
Thomas
Yes Anatoliy, but they're ugly!
If to strip off aluminum shell it looks almost the same, except the key in the socket. It has to be inserted carefully and properly in such naked state...
Rearranged the layout to fit the RCA connectors and the power connector. I left space in the back to bolt the heat sink and the filament board.
I quite like the minimalist look of this preamp. I want to see if I can avoid fitting it in an aluminum case. I have shielded input and output cables, so hopefully that will do the job. Will test and report.
I realised that by lowering the filament current to 500mA I need to change the filament resistor as well. Keen to see if I can notice the difference by changing slightly the quiescent point though...
I quite like the minimalist look of this preamp. I want to see if I can avoid fitting it in an aluminum case. I have shielded input and output cables, so hopefully that will do the job. Will test and report.
I realised that by lowering the filament current to 500mA I need to change the filament resistor as well. Keen to see if I can notice the difference by changing slightly the quiescent point though...
Attachments
Hi Regal,
I did get some 550 paracord from a local epay supplier. Got it today and it's about 3mm thick so will be a bit messy to thread in my current chassis. It's all too tight! Will see what I can do, at the moment replaced the rubber bands with a good multithread cord I had at hand. See previous post..
Cheers,
Ale
I think these have been brought up before. But how about the vibration dampening sandwich mounts.
See page 1368 of the McMaster catalog:
McMaster-Carr
~Tom
See page 1368 of the McMaster catalog:
McMaster-Carr
~Tom
Couldn't one cut the shell with a pipe cutter leaving some 4~5 mm at the bottom. The fill the 'cup' with epoxy to glue the 'cup' to the glass tube. That would preserve the key.
~Tom
Cool wasn't aware of these, will get a couple to try. Not sure if they ship to the UK though...
Thanks Tom!
I completed the pre-amp work today. Got the filament boards, heatsink and wired the multipole connector. My HT supply has a Salas shunt regulator optimised for the 26, so need to tweak the supply to enable driving these 4P1L.
Yesterday was looking at the preamp and realised that most of its parts are Russian: sockets, valves, filament resistor, output capacitors and connectors so decided to name it "The Siberian" 4P1L pre-amp.
Hopefully tomorrow will be able to do a final listening test!
Yesterday was looking at the preamp and realised that most of its parts are Russian: sockets, valves, filament resistor, output capacitors and connectors so decided to name it "The Siberian" 4P1L pre-amp.
Hopefully tomorrow will be able to do a final listening test!
Attachments
No those are for heavy loads, they won't do any good for us, would be like putting a war tank suspension under a Fiat (rough ride).