Super V/i converted (LL1684 )

linuxfan · 2013-12-17 2:28 am

This may be a stupid question - will there be any DC offset at the output? More specifically, at the unbalanced output?

Erlend Sæterdal · 2013-12-17 10:23 am

Absolutely no offset linuxfan

linuxfan · 2013-12-17 12:12 pm

Thanks.

meintan · 2013-12-17 3:23 pm

1. NicMac, 1 set (possibly also the transformers)
2. palmito, 1 set
3. Misterwolf, 1 set = 1(25$)+2(2$)+4(2$)+6(7$)+shipping(10$) = 46$
4. audiodesign, 1 set
5. danielkol, 2 set
6. Mas Penk, 1 Complete kit... Shipping together with DAC kit
7. flowerpot, 1 set
8. Stenachio, 1 set, including all parts (if possible), shipped with DAC kit
9. Sandor, 1 complete set with LL1684, shipping with DAC kit
10. Rowli, 1 complete set with LL1684
11. nkdk 2set. pcb
12. Nick F, Complete kit (items 1-8) ship w/DAC?
13. hordmop, 2 set = 1(50$)+2(4$)+3(13$)+4(4$)+5(10$)+6(14$)+7(76$)+shi p ping(20$) =191$
14. msaywitz: Complete Kit (items 1-8), shipped with DAC kit.
15. MattMax: Complete kit, including LL1684 transformers + shipping.
16. necplusultra, 1 set (possibly also the transformers)
17. flocchini, 1 complete set with transformers
18. gjorgji Complete kit, including LL1684 transformers + shipping
19.myfavoritething 1 complete kit with LL1684 +shipping, + Amareno usb module + LNV and the caps to modify coax and AES output
20. meintan: 1XItem1($25)+1XItem5($5) + 2XItem6($14) + Shipping($10). May I have a dac shield please. Have not received mine.

linuxfan · 2013-12-20 5:22 am

1. NicMac: 1 set (possibly also the transformers)
2. palmito: 1 set
3. Misterwolf: 1 set = 1(25$)+2(2$)+4(2$)+6(7$)+shipping(10$) = 46$
4. audiodesign: 1 set
5. danielkol: 2 set
6. Mas Penk: 1 Complete kit... Shipping together with DAC kit
7. flowerpot: 1 set
8. Stenachio: 1 set, including all parts (if possible), shipped with DAC kit
9. Sandor: 1 complete set with LL1684, shipping with DAC kit
10. Rowli: 1 complete set with LL1684
11. nkdk: 2set. pcb
12. Nick F: Complete kit (items 1-8) ship w/DAC?
13. hordmop: 2 set = 1(50$)+2(4$)+3(13$)+4(4$)+5(10$)+6(14$)+7(76$)+shi p ping(20$) =191$
14. msaywitz: Complete Kit (items 1-8), shipped with DAC kit.
15. MattMax: Complete kit, including LL1684 transformers + shipping.
16. necplusultra: 1 set (possibly also the transformers)
17. flocchini: 1 complete set with transformers
18. gjorgji: Complete kit, including LL1684 transformers + shipping
19. myfavoritething: 1 complete kit with LL1684 +shipping, + Amareno usb module + LNV and the caps to modify coax and AES output
20. meintan: 1XItem1($25)+1XItem5($5) + 2XItem6($14) + Shipping($10). May I have a dac shield please. Have not received mine.
21. linuxfan: 1 kit, WITHOUT LL1684 - items 1-7 (plus shipping)

claudio52 · 2013-12-20 10:56 pm

For a good operation in voltage, what is the resistance seen by ES918? 11.5K are sufficient?

Erlend Sæterdal · 2013-12-21 12:18 am

Today I brought my dac to a friend. I must say the 1684 can not play direct to a power amplifier. It was so much better with my Salas B1 in between.

kevinkr · 2013-12-21 1:44 am

So guys when was the last time any of you heard from the OP? Might try contacting him directly to find out whether he is aware of the level of interest.. (Speaking only for myself)

linuxfan · 2013-12-21 5:20 am

Erlend Sæterdal said:
I must say the 1684 can not play direct to a power amplifier. It was so much better with my Salas B1 in between.

Yes, I wondered about this, myself. What power amp do you have? Balanced or unbalanced?
I suspect the result depends a lot on the particular amplifier.

I recall that at least two people have reported great results using direct-output, straight from DAC chip to (balanced) Hypex UcD amp ...
now I'm wondering whether the money I'm spending on this output stage might have been better put towards a UcD180 amplifier?

Erlend Sæterdal · 2013-12-21 6:49 am

well I think it depends on your upset to if you are able to hear the differences. The B 1 has around 70 kohm input impedance with a 100 kohm pot. The amplifier was around 30 kohm.

The differences was very much the dynamic behaviour and distortion. Was a lack off bass as well without the B 1.

claudio52 · 2013-12-21 9:18 pm

I think that the new discrete differential no feedback output stage is able to do "fly" every amplifier. The signal tranformer is a good choice but you have to check if the input impedance of the amp dampens the risonance of the tranformer ( +3-6dB ). The effects of high frequency can be perceived as a loss of bass.

linuxfan · 2013-12-22 3:14 pm

claudio52 said:
The signal transformer is a good choice but you have to check if the input impedance of the amp dampens the resonance of the transformer

So if transformer and amp don't play well together ... the solution is a buffer in between?
Would a more basic buffer be OK, other than the B1 (or DCB1) that Erlend used ?

claudio52 · 2013-12-22 7:16 pm

The problem is the impedance seen from the secondary of the transformer. If too low, the peak of the resonance (positive peak followed by a dip negative )is not damped. The buffer can not delete it. To linearize the frequency response there two ways.
1) Close the secondary with a low resistance. Unfortunately these loads load too the stage connected to the primary. With my tranformer have a linear response with 20K. The impedance reflected to the primary is only 8.9K. Perhaps they are too low for ES9018.
2) Insert an R-C network on the secondary ( R1-2, C1-2 ). What will, however, its effect on the sound?

linuxfan · 2013-12-23 12:35 pm

Thanks claudio52,
Looking at Quanghao's most recent schematic attached to the first post -
http://www.diyaudio.com/forums/attachments/quanghao-audio-design/384592d1385548552-super-v-i-converted-ll1684-suppler-v-i-ll1684-dac.jpg
I see a 3nF cap plus 1K resistor across the outputs of the secondaries.
So this is an RC network, which should suitably dampen the transformer's resonance?

claudio52 · 2013-12-23 1:22 pm

It is precisely that

linuxfan · 2013-12-23 1:40 pm

Thanks.

jinkslynx · 2014-01-01 8:12 pm

1. NicMac: 1 set (possibly also the transformers)
2. palmito: 1 set
3. Misterwolf: 1 set = 1(25$)+2(2$)+4(2$)+6(7$)+shipping(10$) = 46$
4. audiodesign: 1 set
5. danielkol: 2 set
6. Mas Penk: 1 Complete kit... Shipping together with DAC kit
7. flowerpot: 1 set
8. Stenachio: 1 set, including all parts (if possible), shipped with DAC kit
9. Sandor: 1 complete set with LL1684, shipping with DAC kit
10. Rowli: 1 complete set with LL1684
11. nkdk: 2set. pcb
12. Nick F: Complete kit (items 1-8) ship w/DAC?
13. hordmop: 2 set = 1(50$)+2(4$)+3(13$)+4(4$)+5(10$)+6(14$)+7(76$)+shi p ping(20$) =191$
14. msaywitz: Complete Kit (items 1-8), shipped with DAC kit.
15. MattMax: Complete kit, including LL1684 transformers + shipping.
16. necplusultra: 1 set (possibly also the transformers)
17. flocchini: 1 complete set with transformers
18. gjorgji: Complete kit, including LL1684 transformers + shipping
19. myfavoritething: 1 complete kit with LL1684 +shipping, + Amareno usb module + LNV and the caps to modify coax and AES output
20. meintan: 1XItem1($25)+1XItem5($5) + 2XItem6($14) + Shipping($10). May I have a dac shield please. Have not received mine.
21. linuxfan: 1 kit, WITHOUT LL1684 - items 1-7 (plus shipping)
22. Jinkslynx: Item 1-6+8, have some M-caps on hand. Sum 367,5

Mas Penk · 2014-01-10 6:12 pm

Quanghao : When do we start to pay for this GB? I expect the V/I can be shipped together with the DAC...

quanghao · 2014-01-10 11:04 pm

Mas Penk said:
Quanghao : When do we start to pay for this GB? I expect the V/I can be shipped together with the DAC...

yes i can!
The PCB i make with the DAC V2!
thanks

Mas Penk · 2014-01-12 4:19 pm

Quanghao : I sent you $300 for DP of the V/I.
Please let me know when you have completed all item (GB DAC + V/I)

Super V/i converted (LL1684 )

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