Simple Killer Amp - Listening impressions - Page 52 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 14th June 2006, 10:09 AM   #511
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
Quote:
I have now polypropylene caps installed to RCA inputs and i will take these away
Can I suggest an alternative?

Instal dual RCA inputs.
DC input goes straight to R2 side of C1.
Ac input goes to R1 side of C1.

Then, just swap input plug between sockets for comparison.

The DC input will suit running sub-bass amps/drivers and the AC input for all other upper frequency duties.

BTW. you have fitted R1 before C1.
__________________
regards Andrew T.
  Reply With Quote
Old 14th June 2006, 10:16 AM   #512
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi Pasi,
you have all your amps located together.
Have you considered putting the amps right next to the respective speakers?

I think short speaker cables are one of the biggest improvements to sound quality available to monoblock users, and just to start an argument, passive bi-amping using separate cables to each driver are next highest on my list. I may find that active speakers are higher yet but my experiments here are on the back burner.

I even went as far as locating my passive crossovers on the back of the amplifier terminals and then ran short cables into the speaker drivers with no further jointing (soldered at crossover and driver terminals).
__________________
regards Andrew T.
  Reply With Quote
Old 14th June 2006, 12:06 PM   #513
Pasi P is offline Pasi P  Finland
diyAudio Member
 
Join Date: Jan 2004
Location: Finland
Hi Andrew T,

Thanks for the tips.

Maybe i was bit unclear.
So, my SKA:s are now DC-coupled (C9 shorted). Also DC-block cap C1 is shorted and "moved" to RCA input because quality polypropylene is too big to fit PCB.
I will remove DC-block cap totally because i think that risk that Orion active crossover give DC out should be quite minimal.

About placing amps near speakers. Maybe it is not very good idea in my case because i use (6ch) passive attenuator between active crossover and amp. Thus RCA cable lenght should be keep minimum. Am i right?
If i will some day build some kind of buffer, that will be interesting to investigate though.
__________________
-Pasi
  Reply With Quote
Old 14th June 2006, 01:57 PM   #514
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi Pasi,
remote location of C1 does not stop you fitting dual RCAs.
Have you fitted R1 at the RCA? since C1 is off board.

Does your crossover have DC block on it's outputs? Quite minimal is not good enough!

Is your crossover digital or analogue?
If analogue, you could put the attenuators (two channel) in front of the crossover. If digital, (same as Behringer DCX arrange) then two three channel attenuators (switched) at the amps still allows the short speaker cable philosophy.
__________________
regards Andrew T.
  Reply With Quote
Old 14th June 2006, 02:07 PM   #515
diyAudio Member
 
Join Date: Jan 2002
Location: Cheltenham
Hi Pasi,

excellent write up of your amps. Yep, they do sound superb.

I've got my SKAs completely DC coupled, with the feedback cap removed too. Offset drifts a little, but is quite acceptable. You might find doing the same improves any edginess in the treble.

Dan
  Reply With Quote
Old 14th June 2006, 02:37 PM   #516
Pasi P is offline Pasi P  Finland
diyAudio Member
 
Join Date: Jan 2004
Location: Finland
Hi Andrew T,

R1 is not fitted. Crossover is analogue 3-way.
http://www.linkwitzlab.com/images/gr...asp-blocks.gif

I want use attenuator after crossover to minimize noise from crossover, that is not a broblem thoug.
Crossover has DC-block only at woofer output so do you think it is too risky if amps do not have any DC-block? Anyway DC from crossover is normally well below 30mV.
__________________
-Pasi
  Reply With Quote
Old 14th June 2006, 04:32 PM   #517
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi Pasi,
with active speakers your drivers are at risk if DC gets into the power amps.

I would fit a DC block on every amplifier OR source (crossover).

If you follow the advice of Sparticus then the DC gain changes from 1 to 28. It is imperative that you fit a DC block if C9 is shorted.

I would also consider adding DC detect at the speaker terminals with isolation relays for each speaker output, particularly if you convert to DC amplification. For active speakers this is probably a "nice to have" option to allow delay muting at power switch on until the amps/sources settle down to stable conditions.

All this is irrelvant if you can afford to change your damaged drivers each time something misbehaves.

Noise from the crossover should not be an issue for +29db gain amps. If your LR is that noisy with attenuators before the crossover I would suggest that you should be looking for a better design. There is one exception; very highly sensitive speakers. A combination of amp gain and speaker sensitivity of more than 125db may become noisy on low level signals and 130db will become obtrusive during quieter passages. Your combination are likely to be 119db (+29db & 90db/2.8V).
__________________
regards Andrew T.
  Reply With Quote
Old 14th June 2006, 07:53 PM   #518
diyAudio Member
 
Join Date: Dec 2005
Location: Germany, near Cologne/Bonn
Default SKA's listening impressions

Hi Pasi P,

very nice job done! Clean casings.

I, myself, also are enjoying my 300D (with SMPS) every day and must say, I am with your (sonic) impressions. Easy listening, be it at low or high levels. No fatigue at all.
Presently I am assembling a 2ch 150D version for a friend (two monoblocks in one casing), but with the double PSU in a separate casing. I am not very fond of high pulsed 100Hz currents close to the amps. I am eager to listen to the "little brother" of the 300D.

My 300D's have a large MKP cap at the RCA inputs. Will also make tests with a DC-servo, to remove both caps at input and feddback point. Then, when the home-built preamp will be ready, only one singular cap will be in series with the signal path. All the rest DC-coupled and freed from DC drifts by the DC-servo amp.

kleep it up!javascript:smilie('')
Big Grin

stoeffle.
__________________
...life is an issue with a scarce ressource: time... so let's use it with best effect!
  Reply With Quote
Old 14th June 2006, 08:12 PM   #519
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi Stoeffle,
am I allowed to say "what if" and "speaker protection" in the same sentence?

Adding DC servo and eliminating both DC blocking caps is a nice philosophy.
How does it turn out in practice?
__________________
regards Andrew T.
  Reply With Quote
Old 14th June 2006, 08:53 PM   #520
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Andrew,
Quote:
Adding DC servo and eliminating both DC blocking caps is a nice philosophy.
Adcom and others do the same thing. A thump on turn on as there is a time constant for correction. Until that happens, the natural DC offset exists. The thump may or may not be high enough to hear.

-Chris
  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
Simple Killer Amp - Listening impressions hifryer The Lounge 106 17th January 2006 02:15 PM


New To Site? Need Help?

All times are GMT. The time now is 08:23 PM.


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