Salas hotrodded blue DCB1 build - Page 56 - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 25th October 2010, 09:44 PM   #551
diyAudio Member
 
Join Date: Jul 2006
Thanks
  Reply With Quote
Old 26th October 2010, 03:13 AM   #552
diyAudio Member
 
Join Date: Nov 2009
Location: Vienna
So, have been reading all the thread, and I would like your opinion on the following matters. I think I will try the 10R and the 3R3 versions:

Power transformer: I live now in Japan that has 100 V, but I will move sooner or later back to Europe. So I was thinking to buy a transformer 115/230 primary and 18-0-18 out. This will give my 15.6 V in Japan and 17 V in Europe. The alternative is to have a 15-0-15 V secondary and run at 13 V while in Japan. I can change resistors when I move.
I have to choose between the R26-22 and the R26-34 by DIYclub

What do you think is better ?

Potentiometer: I think I will choose a 20 K pot. Does it make sense to use a stepped attenuator ? advantages and disadvantages ? I'd love to install something that I can remotely control in the final build, suggestion ? Lightspeed is also an option.

I will use the buffer mainly between the DAC and the Power amplifier. The DAC (DAC-END2) has a tube output with 1 5687 with the sections in parallel and 1 mF output cap. I have various amp, but they all start with a tube (5842, 6N1P, 12AX7). I plan to play with i/v stages anyway.
Does it make sense to use two buffers before and after the pot. It looks like in the Pass Lab threads they think this is the best solution.

For the resistors I think I will use Caddok for the signal. I am tempted by the Foil one for the 220R, but they cost 15 $ any cheaper source ?

Also, I did not find a source for the pot. Any suggestion ? I find only 10k or 50k.

Output caps: Am I right thinking that with OPTs before the speakers there is no way of getting DC on the speakers ? Worst case scenario, if there is a problem with the buffer, the bias of the input tubes will change if I have some DC, although with leds on the cathodes this should not happen.

Thanks,

Davide
  Reply With Quote
Old 26th October 2010, 03:29 AM   #553
diyAudio Member
 
Join Date: Nov 2009
Location: Vienna
Could this fit as pot choice ?

Hi-End Volume Control DIY Kit,LED, Remote Control /V-03 - eBay (item 290485343961 end time Nov-07-10 04:10:12 PST)

It says max out impedance 22K.

Thanks,

Davide
  Reply With Quote
Old 26th October 2010, 03:39 AM   #554
diyAudio Member
 
Join Date: Nov 2009
Location: Vienna
In case I go for the stepped attenuator. Do I need a string attenuator, or can I use a shunt attenuator ?

Thanks,

Davide
  Reply With Quote
Old 26th October 2010, 03:44 AM   #555
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
The RC kit is fine for DCB1.

15-0-15. 13V is still enough. Running hot rod you skip much CCS heat VS 18-0-18.

See about Vishay RNC90Y too. Bulk foil.

No DC when OPTs.
  Reply With Quote
Old 26th October 2010, 04:59 AM   #556
diyAudio Member
 
Join Date: Nov 2009
Location: Vienna
Mouser have the 215 ohm Vishay RNC90Y would they work ?

D.
  Reply With Quote
Old 26th October 2010, 09:24 AM   #557
diyAudio Member
 
LucasAdamson's Avatar
 
Join Date: Feb 2009
Wow! not cheap, those!

You could also try the highly regarded Vishay Naked Z foils if you're spending:

Vishay VAR-Series "naked" Z201 Z-FOIL RESISTOR

Regarding values, Nelson Pass originally had them at 1K, and they were reduced by popular consent/dissent, (based on reports of tighter bass with more drive) to 220R, which Papa agreed with I believe, warning however, that the lower value you go, you increase risk of parasitic oscillation. So, you can choose any similar value and be safe, and go up to 1K, but I can confirm that it sounds better near to 220R.
__________________
Lucas
  Reply With Quote
Old 26th October 2010, 09:54 AM   #558
diyAudio Member
 
Join Date: Nov 2009
Location: Vienna
What about using one or two buffers ? (before and after)

Lucas, I saw that, I was looking for a cheaper source of them. 15 $ for a resistor make me think about. I mean, I have other cheap resistors between my DAC and the speakers (not many around 5). Unless I don't replace them all, I am not sure it would be worth it.


Thanks,

D.
  Reply With Quote
Old 26th October 2010, 10:21 AM   #559
Tea-Bag is offline Tea-Bag  United States
not politcally affiliated
diyAudio Member
 
Tea-Bag's Avatar
 
Join Date: Feb 2006
Location: Kennebunk
Blog Entries: 7
Vishay Z-Foils. TX2575. I dont think you'll regret the investment, especially if there is something else in their first to try.

Direct from texas instruments I get them for for about 10.00 each before shipping and handling. That may be another $10.00 for that. Maybe more for asia shipping. Anyone can order from there I think, even just 1 resistor.

Use caddock for 220k, 1M anything else IMO.
  Reply With Quote
Old 26th October 2010, 10:50 AM   #560
diyAudio Member
 
LucasAdamson's Avatar
 
Join Date: Feb 2009
I am using PRP Audio grade Metal Film resistors, which cost 30c each. The price/quality ratio for these is unsurpassed, period.

I think it's pretty ridiculous to spend that kind of money on resistors before you've let the circuit settle in - like using $30 silver/gold film caps in a power supply or gold wiring.

For me, such resistors would be a potential tweak for a year or so down the road, if I felt the need. That way you can hear for yourself if you've wasted you're money or not.
__________________
Lucas
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
dcb1 buffer with shunt reg. merlin2069er Swap Meet 0 3rd August 2010 05:25 PM
F2 and DCB1 parts selection - please advice! DQ Pass Labs 6 25th November 2009 03:20 PM
Y B Blue - how blue LED improves the CD playback Peter Daniel Digital Source 176 25th September 2003 07:40 AM


New To Site? Need Help?

All times are GMT. The time now is 01:29 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2