CHANGSTAR: Audiophile Headphone Reviews and Early 90s Style BBS

Lobby => DIY => Topic started by: cspirou on September 15, 2015, 10:14:44 PM

Title: Nobsound OTL amp
Post by: cspirou on September 15, 2015, 10:14:44 PM
I found this OTL amp kit on ebay.

http://www.ebay.com/itm/6N5P-6N11-France-6080WA-Czech-JCC88-single-end-Class-A-tube-amp-headphone-KIT-/281345606934?&tfrom=281345614556&tpos=unknow&ttype=price&talgo=origal&autorefresh=true

The basic PCB without tubes or a transformer is $35 and the fully assembled version is $130-$180 depending on the options you want. From the schematic is looks identical to the OTL amp by Aren Van Waarde on headwize and similar to other 6AS7 amps like the Bottlehead Crack.

http://www.illuwatar.se/project_pages/6as7_headphone/headphone.htm

Given the similarities, is there any reason why this wouldn't sound as good as a stock Bottlehead Crack?
Title: Re: Nobsound OTL amp
Post by: OJneg on September 16, 2015, 12:35:12 AM
Crack's circuit is a lot more refined with CCS loading and CRCRC power supply. Also more room for upgrades like caps, chokes, pots, etc. that can be easily done via P2P wiring. So same circuit concept in essence, but more room for mods for those looking to scale things up. What you have there is essentially a stock Crack in PCB form. Ask some pirates what they think of stock Crack's sonics.....
Title: Re: Nobsound OTL amp
Post by: CEE TEE on September 16, 2015, 12:56:22 AM
^Yeah- listening to Crack with Speedball upgrade and modded HD800 right now.  Fun, big, lush sound.  Much better with Speedball in and now I actually want to listen to this amp more.  Not the tightest/most resolving/fastest amp but plays really well with modded HD800 and I can crank them up like I cannot on other amps.  Enjoyable as I work and yes- a good pairing.  Without the Speedball, I wasn't really called to listen to it even though I built it and was proud that we were both alive. Now I want to keep it out of more than "first amp built and no issues".  :-\  [size=78%] [/size]
Title: Re: Nobsound OTL amp
Post by: cspirou on September 16, 2015, 06:09:04 AM
Crack's circuit is a lot more refined with CCS loading and CRCRC power supply. Also more room for upgrades like caps, chokes, pots, etc. that can be easily done via P2P wiring. So same circuit concept in essence, but more room for mods for those looking to scale things up. What you have there is essentially a stock Crack in PCB form. Ask some pirates what they think of stock Crack's sonics.....

I would think that the Nobsound is a better power supply since it appears to be regulated with a DC heater instead of AC. I agree that upgrading is easier on a P2P circuit then on a PCB but I don't see why you couldn't use an offboard CCS during the initial build.
Title: Re: Nobsound OTL amp
Post by: OJneg on September 16, 2015, 06:26:43 AM
I would think that the Nobsound is a better power supply since it appears to be regulated with a DC heater instead of AC. I agree that upgrading is easier on a P2P circuit then on a PCB but I don't see why you couldn't use an offboard CCS during the initial build.


Sure, you just have to design and build the circuit yourself. Ain't DIY grand?
Title: Re: Nobsound OTL amp
Post by: cspirou on September 16, 2015, 08:13:14 AM

Sure, you just have to design and build the circuit yourself. Ain't DIY grand?

I'd rather use the CCS modules at K&K sound.

http://www.kandkaudio.com/other-kits/
Title: Re: Nobsound OTL amp
Post by: joch on September 16, 2015, 03:53:40 PM
you can definitely spend more on upgrading it than on its original price