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"Lacewood" Amp V2.0
http://diyaudioprojects.com/Forum/viewtopic.php?f=9&t=5736
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Author:  mike567 [ 18 Mar 2018, 08:27 ]
Post subject:  Re: "Lacewood" Amp V2.0

A must have if Harbor Freight is near: https://www.harborfreight.com/180-piece ... 67582.html

Author:  mwhouston [ 19 Mar 2018, 13:06 ]
Post subject:  Re: "Lacewood" Amp V2.0

Suncalc wrote:
These are much cheeper, but I don't know if the shipping would make them expensive for you as well.
https://www.tubesandmore.com/products/grommet-rubber-chassis


I generally don't bother but over-drill my holes to allow some wiggle room. Not only wiggle room for the wires but just aligning trannies and wires etc. Also I ensure all is burr free. With the top plate being earthed should any mains or HT connect it should take out the fuse.

A practice I have employed since my first tube amp is half width rubber grommets under power trannies, chokes and OPTs to help isolate any vibrations. The power trannies under load can buzz a bit. Mounting them on split grommets helps stop that vibration getting to the tubes etc. a simple and cheap practice. If you place your finger lightly on a power trannies usually a small vibration can be felt. Not good for tubes big or small. It also helps with any mechanical noise from the amp which the top plate may act as a sounding board.

Author:  mwhouston [ 19 Mar 2018, 13:08 ]
Post subject:  Re: "Lacewood" Amp V2.0

P.S. I like the baby blue too. My next HP amp, on a dark wood base, will have a deep blue top plate. Just to get away from too much black.

Author:  lowhifi [ 22 Apr 2018, 18:16 ]
Post subject:  Re: "Lacewood" Amp V2.0

I start the build of a second Lacewood but James audio stop their production so i need an alternative.

Lundahl transformers seems nice, the LL1663 may suit my needs at 8 ohm.

http://www.lundahl.se/wp-content/upload ... s/1663.pdf

What do you think.

Regards.

Author:  Chris65 [ 22 Apr 2018, 18:57 ]
Post subject:  Re: "Lacewood" Amp V2.0

Yes, such a shame James Audio have stopped production of their transformers.
I have used the LL1663, and these a very good. Depending where you are, Thomas Mayer http://vinylsavor.blogspot.com has good prices on Lundahl products. Another good option is Electra-Print in the USA http://www.electra-print.com/transformers.php.

Author:  lowhifi [ 26 Apr 2018, 17:49 ]
Post subject:  Re: "Lacewood" Amp V2.0

I am living in Canada, so not very much options locally. Hammond no, maybe Plitron.

And what about the expensive japanese transformers,not at 4000$ but maybe 2000$

Also i will use my two Lacewood amp in a bi-amp setup. I already James JS6135-HSF so maybe the new ones can be chosen accordingly for higher or lower frequencies.

All my drivers are 8 ohm and i cut at 700hz.

Regards

Author:  lowhifi [ 05 Jun 2018, 14:45 ]
Post subject:  Re: "Lacewood" Amp V2.0

A Lundahl distributor in France ask me for the steady current "courant de repos" 50 mA he think, is that correct.
For LL1663 the price is Ok but i saw on Ebay large 2kg open frame c core UL transformers with no name for the same price. :confused:

Author:  Suncalc [ 05 Jun 2018, 19:25 ]
Post subject:  Re: "Lacewood" Amp V2.0

lowhifi wrote:
A Lundahl distributor in France ask me for the steady current "courant de repos" 50 mA he think, is that correct.
In the Lacewood V2.0 the total transformer current (plate plus screen) is ≈43mA with a B+ of 300V.

Author:  lowhifi [ 05 Jun 2018, 21:05 ]
Post subject:  Re: "Lacewood" Amp V2.0

Thanks a lot.

But the LL1663 SE come in two versions. 50 mA/35H or 100 mA/17H

What will be the difference in the circuit.

Best regards.

Author:  Suncalc [ 05 Jun 2018, 22:45 ]
Post subject:  Re: "Lacewood" Amp V2.0

lowhifi wrote:
What will be the difference in the circuit.
The circuit should stay the same.

However, the low frequency response will be much better with the 50mA transformer due to the higher primary inductance.

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