After installing starground and decoupling caps the amp is now
stable as a rock. No hum or other noise, just crystal clear sound.
A few things remains though:
-Cannot adjust dc out lower than 0.8V.
-T8 and T11 gets very warm. Specs for 2sc2240/2sa970 is 0,3w.
I measure 0,480w which is over the specs. Should I forget this and just mount a cooler on the transistors?
The problems are exactly the same on right and left channel.
stable as a rock. No hum or other noise, just crystal clear sound.
A few things remains though:
-Cannot adjust dc out lower than 0.8V.
-T8 and T11 gets very warm. Specs for 2sc2240/2sa970 is 0,3w.
I measure 0,480w which is over the specs. Should I forget this and just mount a cooler on the transistors?
The problems are exactly the same on right and left channel.
Hi Jan
I have had the same problems you metion. The DC out i just leave alone, my speakers do not seem to care about a few mV. The hot t11/t8: I originally had to lower the value of r22 (to 120R i think) in order to get the bias current low enough. I think this lowered the dissapation in t11/t8 as well. I might be wrong here, maybe someone with more insight can analyse the schematic for us and explain this. But I think it is commonly known that the original values for the end MK2 resulted in too high a bias current in the output stage.
Nice to hear that you got it to work in the end... This amp really punish you when you get the grounding scheme wrong, but once it plays, it's just wonderful!
I have had the same problems you metion. The DC out i just leave alone, my speakers do not seem to care about a few mV. The hot t11/t8: I originally had to lower the value of r22 (to 120R i think) in order to get the bias current low enough. I think this lowered the dissapation in t11/t8 as well. I might be wrong here, maybe someone with more insight can analyse the schematic for us and explain this. But I think it is commonly known that the original values for the end MK2 resulted in too high a bias current in the output stage.
Nice to hear that you got it to work in the end... This amp really punish you when you get the grounding scheme wrong, but once it plays, it's just wonderful!
I have now tried several values on r22. It doesn't affect t8/t11 at all, it just makes it harder to adjust idle current.
About the dc out problem:
Same thing for me; the speakers doesn't seem to care. I cannot
see any movement on the woofers during powerup so I'm
thinking of let it be that way.
About the dc out problem:
Same thing for me; the speakers doesn't seem to care. I cannot
see any movement on the woofers during powerup so I'm
thinking of let it be that way.
Could someone repost the schematic? It seems all external links have broken, that is why it’s better to attach then it is to link.
Hi, LC
It's a very nice design !😀
It's very different from your End Millenium (SMD parts). How is the sound comparison to the SMD version (your product)?
What is the gain of this amp (what resistors determine it)?
How much bias to be set at the output, and how to do it?
It's a very nice design !😀
It's very different from your End Millenium (SMD parts). How is the sound comparison to the SMD version (your product)?
What is the gain of this amp (what resistors determine it)?
How much bias to be set at the output, and how to do it?
Thank you Lars,
I have already ordered a Millennium XP a week ago. I expect it any day now. I just like to see how your thinking evolves over the years. It would also be nice to see the MK 3.
Leve
I have already ordered a Millennium XP a week ago. I expect it any day now. I just like to see how your thinking evolves over the years. It would also be nice to see the MK 3.
Leve
LC Audio The End Mk3.1
...old tread, but it seems subtable to use it for this question 🙂
I'm in the process of reconfiguration my The End Mk3.1 from single ended to support both RSA and XLR.
I'll replace the R28 strapping with a 301 ohm resistor and implement the external 301E resistor and switch as the diagram show.
But the value of R27 it is unclear to me when I use the optional resistor/switch. 😕
tia
regards
Hans
...old tread, but it seems subtable to use it for this question 🙂
I'm in the process of reconfiguration my The End Mk3.1 from single ended to support both RSA and XLR.
I'll replace the R28 strapping with a 301 ohm resistor and implement the external 301E resistor and switch as the diagram show.
But the value of R27 it is unclear to me when I use the optional resistor/switch. 😕
tia
regards
Hans
Attachments
@Lars
What is the damping factor for The end Millenium and what is the real power on 1khz before clipping with that 2 Tip parallel on each side?
What is the damping factor for The end Millenium and what is the real power on 1khz before clipping with that 2 Tip parallel on each side?
Hi Felix,
why do you want damping factor?
If you think you really need it, then measure open circuit output voltage, then load with 1k and again with 8r and re-measure the output voltages.
Do this at the various frequencies you are interested in.
Repeat the measuring process at other voltage output levels.
You will now have a lot more data than any retailer is ever willing to supply.
why do you want damping factor?
If you think you really need it, then measure open circuit output voltage, then load with 1k and again with 8r and re-measure the output voltages.
Do this at the various frequencies you are interested in.
Repeat the measuring process at other voltage output levels.
You will now have a lot more data than any retailer is ever willing to supply.
Yes ....you are right...but-- I want to made a new project and maybe some owners know that data's.
My amps need more damping factor because I intend to puting to drive 15" bass driver into open baffle (speakers).
That "kind" of nonenclosure needs that.
Also I need 200-300W/8 ohms but with a real good extension on the lower freqv....not paper writings.
My amps need more damping factor because I intend to puting to drive 15" bass driver into open baffle (speakers).
That "kind" of nonenclosure needs that.
Also I need 200-300W/8 ohms but with a real good extension on the lower freqv....not paper writings.
the millenium XP with tube driver
dear
its maybe a litle late to answer.
I only wantet to tell you that I build a amp
with the millenium XP output stage, but for the voltage amplifier I used
a ECF82 tube.I used 2 current sources for the voltage amp, and 2 extra
current soures for the output stage.
But it was difficult even with servo op to bring the offset voltage down.
The sound was unbelievable, the signal at the input was the same as that in the output, only much stronger.
But when I switched on the output blow, maybe due to lacking turn on delay relay.
I hope, I will find the time to make it running again...
cheers
dear
its maybe a litle late to answer.
I only wantet to tell you that I build a amp
with the millenium XP output stage, but for the voltage amplifier I used
a ECF82 tube.I used 2 current sources for the voltage amp, and 2 extra
current soures for the output stage.
But it was difficult even with servo op to bring the offset voltage down.
The sound was unbelievable, the signal at the input was the same as that in the output, only much stronger.
But when I switched on the output blow, maybe due to lacking turn on delay relay.
I hope, I will find the time to make it running again...
cheers
Member
Joined 2009
Paid Member
No feedback amps haven't gone out of fashion yet, there's still interest for them. I didn't hear much about The End amplifier and this thread suggests that it is a design that (when built properly) sounds very nice. Are there any people still using this amplifier care to comment about whether it is still good by todays standards ?
I had a dual amp setup with The End and two super power modules running for many years. Stopped using them after listening to SI-5066 T-Amp in the same setup. It was like lifting 4 layers of carpets of the speakers. The little T-Amp have much more details to offer in the mid and high range.
As a former drummer I tend to use hi-hat and cymbal sounds as reference. The only traditional transistor amp I've listen to that come close to reproduce the complex sound of a cymbal like the little T-amp was a 18000US$ Norwegian build monster-amp out of production years ago.
15 different amplifiers built with "The End mkII" circuit
....... it's long time ago...but anyway.....
My friend has made a least 15 different DC amplifiers with the circuit "The End mk.II" ...and two "The End mk3.1"... Even the first 1989 "The End mk I" is still running and plays very well. We did not find the same "free sound experience" and "hole through" with "The Millennium", but you have to try and test the different amps, to be sure.
We have tried several expensive factory made solid state amplifiers like AR, Mac, ML and Krell, and still "The End mk.II" comes up with tweeter micro details, totally clear defined midrange and a significant thunder deep bass reproduction, where you have to buy a very expensive solid state amplifier just to reach the sound quality of "The End mk.II" .
Then to be said....before you get so far with a DC-coupled amp like "The End mk.II" there are some guidelines to be followed.
Every transistor have to be matched pair by pair....from the input, driverstage to the output transistors. The input zeners has to be matched as well as several of the 625mW resistors...use quality emitter resistors. Use one PSU per channel and four bridges.....take care not to "open" the power rail wires in order to avoid oscillation. Keep the main power wires short from the power capacitors to the amplifier PCB. The on-board PCB small signal transistors must have close heat contact, and the output transistors need very large heatsinks to keep a stable heat balance. Don't exceed +- 58VDC...after this many details in sound seems to disappear
If one follows the advises above the approx. DC-out stays around +-7/8 mV ...without any feedback and servo...and the sound after one week of burn-in is very excellent.🙂
https://sites.google.com/site/httpstubeamp/home/nad-3080/the-end-mk2-dc-amplifier
....... it's long time ago...but anyway.....
My friend has made a least 15 different DC amplifiers with the circuit "The End mk.II" ...and two "The End mk3.1"... Even the first 1989 "The End mk I" is still running and plays very well. We did not find the same "free sound experience" and "hole through" with "The Millennium", but you have to try and test the different amps, to be sure.
We have tried several expensive factory made solid state amplifiers like AR, Mac, ML and Krell, and still "The End mk.II" comes up with tweeter micro details, totally clear defined midrange and a significant thunder deep bass reproduction, where you have to buy a very expensive solid state amplifier just to reach the sound quality of "The End mk.II" .
Then to be said....before you get so far with a DC-coupled amp like "The End mk.II" there are some guidelines to be followed.
Every transistor have to be matched pair by pair....from the input, driverstage to the output transistors. The input zeners has to be matched as well as several of the 625mW resistors...use quality emitter resistors. Use one PSU per channel and four bridges.....take care not to "open" the power rail wires in order to avoid oscillation. Keep the main power wires short from the power capacitors to the amplifier PCB. The on-board PCB small signal transistors must have close heat contact, and the output transistors need very large heatsinks to keep a stable heat balance. Don't exceed +- 58VDC...after this many details in sound seems to disappear
If one follows the advises above the approx. DC-out stays around +-7/8 mV ...without any feedback and servo...and the sound after one week of burn-in is very excellent.🙂
https://sites.google.com/site/httpstubeamp/home/nad-3080/the-end-mk2-dc-amplifier
Last edited:
Build both first second and millilenium,the first one i use Bc 650-550 C,function very good , has the original papper Hihg fidelity,has little higher gain as millenium,some he cald little '' fnas in treble region but sounds good without feedback loop.
Regard Alec
Regard Alec
- Status
- Not open for further replies.