Wanted Hammond PP opt’s 1650HA

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Paul Barker
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Wanted Hammond PP opt’s 1650HA

Post by Paul Barker » Sat Jun 27, 2020 7:17 pm

As it’s secondary is correct for matrix. 1650HA is a 40 watter but as It’s for Barbaric with it’s EL34’s output valves I could get away with the 1620A for 20 Watts. Either please or any transformer wound for push pull wherein the secondaries are on one long winding tapped 4, 8, 16 ohm.

Ordinarily we would class this as sub standard, but not with Matrix.
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Re: Wanted Hammond PP opt’s 1650HA

Post by steve s » Sat Jun 27, 2020 11:29 pm

I've got a pair of el34 pp transformers I see what the secondary are paul
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Re: Wanted Hammond PP opt’s 1650HA

Post by Paul Barker » Sat Jun 27, 2020 11:35 pm

mint secondary must be one continuous winding, tapped ta 4, 8, 16 ohm. As picture, but ignore Stephies misprint 10 should be 16.Image
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Re: Wanted Hammond PP opt’s 1650HA

Post by Paul Barker » Sat Jun 27, 2020 11:37 pm

Think I’ll knock Graffic Designer off my bucket list.
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Re: Wanted Hammond PP opt’s 1650HA

Post by Paul Barker » Sat Jun 27, 2020 11:47 pm

It’s just that aswell as making a brute of a matrix amp that’s not family life compatible, I want one I can use all the time.

The input transformer resides in the unbal to bal preamp Ant made me. For the GK71 matrix I need it reconfigured and I’ll change preamp output from bal back to unbal.

Now you see the preamp is the first part of both matrix amps. For which output side of second IT is configured goofy and it was previously dedicated to a balncced PP amp. If possible I would add another phono out for to drive the ACFII and that progect gets its dc isolation without purchasing more line input transformers for which.

Stephie requires 6em8 to receive 200v at anode and derives it from the shared duty load/feedback resistor. So that will get adjusted down in value to balance up which might require some lowering of anode voltage @6em8.

I’m not chuffin switching opt’s (although I ought to think that through, maybe that is my answer.)

Steve Cresswel’s voltages which have stead the amp in good stead push pull could remain as is , but unbeknown to them, they’ll be single ended! I supose the advantage is worth aiming for, Lundahl cost baout 5 times the Hammond, and more suited to Matrix.

So perhaps I need to think of a safe way to plug transformers in to sockets duplicated in each amp. Why stop there? Buy two more GK71 bases as an option for the class A1/A2 pure SE amp. One pair gk71 only required.
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Re: Wanted Hammond PP opt’s 1650HA

Post by Paul Barker » Sun Jun 28, 2020 1:02 pm

Having spent the morning listening properly to Barbaric I can’t flip it to a Matrix. It is that good, it deserves locking in as a point of reference.

Plus it’s totally reliable!

Plus when you look at the operation of the pentodes all the journey Steve was on at the time were valuable. The whole journey not just this balanced amp.

It is a really good amp.

The GK71 Matrix is next. If that blows me away and the Barbaric no longer satisfies, I’ll make a less bold Gk71 Matrix which doesn’t have to be a boat anchor. For daily use, since gk71 are cheap.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein

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