krell ksa5 klone

[jack]

Cryo’ing should slow it down a bit.

Is it sarcasm or sth. I do not understand?


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[nopants]

do you know how the opamp is being used?

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[spritzer]

Let's not dwell on the specifics of how something actually works. 

[wink]

Yeah, if it sounds good doesn't necessarily mean it is good......

[jack]

1 hour ago, wink said:

Yeah, if it sounds good doesn't necessarily mean it is good......

True! If it sounds good does not necessarily mean it will taste good ;-)
Since good is subjective what does good mean to you in audio gear? in what area doen an opamp has to excel in order to be qualified as good?

[JimL]

2 hours ago, jack said:

 in what area doen an opamp has to excel in order to be qualified as good?

Depends on what its function is. As Kevin Gilmore points out, for a servo, an op amp with virtually no offset current (JFET rather than bipolar) and low temperature drift, that is slow (since the servo is monitoring for DC offset and is deliberately slowed down anyway), is good. OTOH may sound like crap as an amplifier, where the requirements for "good" are significantly different.

[Helium]

Did anyone run KSA5 at 30VDC?

I like all my dynamic amps running at 30VDC.

I'm scared a bit to fire it up. Don't want to fry anything. Balanced version was more difficult and expensive to make than I expected.

P.S. I'm using OPA445 and G5V-2-H1-DC24 relays. And all other components are according to BOM and PCB silkscreen.

[rumina]

do you made a balanced ksa5 with two boards? some pictures would be nice :-)

[Helium]

I'm making it. Boards are ready, paired with 2xGRLV and nice amb's deltas. Cases are not))

[hy2a3]

Anyone have a Kevin's KSA5 bare board to sell?   Waiting for all my parts to arrive, intending to build on an Ebay Chinese board clone by Zero Zone.  Thought better and will not use;  I want to be certain that the board I use have 2oz of copper.   Thanks.  

[grendel23]

I used a Zero Zone board. I don't know the weight of the copper, but the board was nicely made.

[hy2a3]

Thanks for the ZeroZone experience.   Got did get reply from Ebay seller "DiyTalent86", the Zero Zone Assembled KG KSA5 board is 1 oz copper.  

[Pars]

Did a quick search back for copper weight and saw the 3oz recommendation. Ran across the special audiophool cable that blew up some poor guys actual KSA5 and found that those fucks are still in business!

Revelation Audio Labs

jeebus...

Edited March 27, 2018 by Pars

[hy2a3]

Head-Case.org amazes me.  Just added to my religious lexicon.

Anyway, Is Dr. Kevin Gilmore's KSA5 Gerber file locked away in a vault?  Can't seem to locate the gerber zip to build a single board to myself.   Will  cost $$$, but I need to do this right avoiding the Chinese clone temptation.   Help anyone, if the zip is still open to private use (not commericial).

 

[Pars]

Look in the Stax thread for the current archive location.


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[penmarker]

10 hours ago, hy2a3 said:

Head-Case.org amazes me.  Just added to my religious lexicon.

Anyway, Is Dr. Kevin Gilmore's KSA5 Gerber file locked away in a vault?  Can't seem to locate the gerber zip to build a single board to myself.   Will  cost $$$, but I need to do this right avoiding the Chinese clone temptation.   Help anyone, if the zip is still open to private use (not commericial).

 

There ya go

https://drive.google.com/drive/folders/0B_iJFfZStuVhSE5nOHBVdTByR1k?usp=sharing

[hy2a3]

1 hour ago, penmarker said:

 Thank You.   Wow, Dr. Gilmore's contribution is overwhelming.

 

 

[davve]

I was wondering if it is okay to use 47pf or 100pf instead of the 33pf's.

 

Thanks

[kevin gilmore]

you will effect the frequency response. best to use the right part in this case.

[davve]

I bought my kit from the link below, it is your version?
But i was wondering, on the board it says 2x 10k ohms resistors and 2x 1k ohm resistors. But i got 4x 10k ohm resistors. 

https://www.ebay.com/itm/Power-supply-board-for-KG-version-KSA5-headphone-amp-PSU-DIY-kit-and-finished/122365758658?hash=item1c7d914cc2:m:mfcUM96JgKu8Wbo08L6PZFw

 

[kevin gilmore]

Yes that is one of my layouts, not in a position to look up schematic/board at the moment.

[Pars]

10 hours ago, davve31 said:

I bought my kit from the link below, it is your version?
But i was wondering, on the board it says 2x 10k ohms resistors and 2x 1k ohm resistors. But i got 4x 10k ohm resistors. 

https://www.ebay.com/itm/Power-supply-board-for-KG-version-KSA5-headphone-amp-PSU-DIY-kit-and-finished/122365758658?hash=item1c7d914cc2:m:mfcUM96JgKu8Wbo08L6PZFw

 

I guess I get the allure of kits from ebay for the cheap prices, assuming the components are a) genuine, and b) decent quality.

However, buying a kit and then coming on here without apparently doing a modicum of research first is very bad form. The links to Kevin's board files and schematics/other files are here, but might require a bit of digging. Since that vendor supplies both kits and built units (for a whopping $10 more), one might assume that they build with the same parts as they supply in the kit, and it might not matter whether you use a 1K or 10K resistor in the 2 spots. If you're worried about it, then use some 1K for those two positions.

But otherwise, the appropriate head-case response is...      

[davve]

6 hours ago, Pars said:

I guess I get the allure of kits from ebay for the cheap prices, assuming the components are a) genuine, and b) decent quality.

However, buying a kit and then coming on here without apparently doing a modicum of research first is very bad form. The links to Kevin's board files and schematics/other files are here, but might require a bit of digging. Since that vendor supplies both kits and built units (for a whopping $10 more), one might assume that they build with the same parts as they supply in the kit, and it might not matter whether you use a 1K or 10K resistor in the 2 spots. If you're worried about it, then use some 1K for those two positions.

But otherwise, the appropriate head-case response is...      

My apology then for using the krell thread. I have read the thread and was just wondering if there been some changes.

Cause 10k or 1k input for the op27 is some diffrence.

 

Perhaps i like to solder?

 

 

 

 

[kevin gilmore]

It really depends on which resistors were changed. If they gave you a schematic, please post it.

Edit: found the schematic.

you can replace the 1k with 10k resistors. The power supply will come up a bit slower, but it will otherwise work.

Edited June 20, 2018 by kevin gilmore

[Pars]

Perhaps I was a bit harsh?

The 1K resistors I see on the schematic I have are on the collectors of Q1/Q2, feeding the + inputs on the error amp. Not sure if going 10K here would make any difference whatsoever.

 

ksa5psschem.pdf