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"Lacewood" Amp V2.0
http://www.diyaudioprojects.com/Forum/viewtopic.php?f=9&t=5736
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Author:  john55 [ 14 Mar 2019, 01:50 ]
Post subject:  Re: "Lacewood" Amp V2.0

Suncalc wrote:
john55 wrote:
That's saved me a few euros. I was going to order some KT-88s in the new year.
Maybe I'll do a KT88 SE-UL bias optimization study when I'm through with the 6L6. I think it might be interesting.

More work with that beautiful little test jig you've built?

Author:  lowhifi [ 15 Mar 2019, 13:15 ]
Post subject:  Re: "Lacewood" Amp V2.0

I put a .22uf coupling capacitor i had in hand instead of the .1uf in my second Lacewood, any counter indication?
Anyway the .22uf duelund is a great improvement over the .1uf auricap, maybe a little less high frequency.
Regards.

Author:  ILoveHiFi [ 15 Mar 2019, 17:36 ]
Post subject:  Re: "Lacewood" Amp V2.0

In theory the 0.22uF will increase low frequency response maybe bit more base.
In theory it will not reduce hf because 20khz is still way too low for series inductance of capacitor to start killing amplitude

Author:  lowhifi [ 17 Mar 2019, 16:30 ]
Post subject:  Re: "Lacewood" Amp V2.0

Ok maybe it was just my impression or the cap was sleeping for to long. I made tests with a signal generator and a sonometer and there's no real difference if i add a .47uf in serial with the .22uf.

There's a big deal on Duelund caps at partsconnexion until the end of the month, up to 60%, great deal but i will buy only a pair of .1uf of the RS line at 30% to put in my other Lacewood for the lower frequency (i don't want more bass) and use the .47uf for the 4S preamplifier. :headphones:

Matt didn't seems to use fancy passive parts for his projects.

Regards.

Author:  lowhifi [ 17 Mar 2019, 16:33 ]
Post subject:  Re: "Lacewood" Amp V2.0

[quote="lowhifi"]Ok maybe it was just my impression or the cap was sleeping for to long. I made tests with a signal generator and a sonometer and there's no real difference if i add a .47uf in serial with the .22uf.

There's a big deal on Duelund caps at partsconnexion until the end of the month, up to 60%, great deal but i will buy only a pair of .1uf of the RS line at 30% to put in my other Lacewood for the lower frequency (i don't want more bass) and use the .47uf for the 4S preamplifier. :headphones:

Matt didn't seems to use fancy passive parts for his projects. :up:

Regards.

Author:  Chris65 [ 17 Mar 2019, 16:58 ]
Post subject:  Re: "Lacewood" Amp V2.0

0.47uf in series with 0.22uf = 0.15uf

Author:  ILoveHiFi [ 18 Mar 2019, 02:06 ]
Post subject:  Re: "Lacewood" Amp V2.0

Fancy parts get you better sound, geniune metalised polypropene gets you most sound quality gains and good for low end amps.
Mid high end amp schematics you want fancy caps like erse pulse x.

Author:  lowhifi [ 22 Mar 2019, 00:13 ]
Post subject:  Re: "Lacewood" Amp V2.0

Hello.
I want to know if it's possible to lower the gain on the Lacewood 2.0 i didn't put a volume control on the two i build.

Can i use weak 6v6 without any worries.

Regards.

Author:  Suncalc [ 22 Mar 2019, 08:52 ]
Post subject:  Re: "Lacewood" Amp V2.0

lowhifi wrote:
I want to know if it's possible to lower the gain on the Lacewood 2.0
Yes. First, remove the 33µf bypass cap on the driver. This will result in about a 6dB gain reduction. After that, a 250kΩ resistor in series with the input and using a 250kΩ grid resistor behind that on the input will form a -6dB pad to further reduce the overall gain.

The first change will subtly alter the sound. The second will not.

Author:  mwhouston [ 22 Mar 2019, 16:43 ]
Post subject:  Re: "Lacewood" Amp V2.0

Good to know.

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