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 Post subject: Re: A new 300B amp project
PostPosted: Sep Wed 13, 2017 10:50 pm 
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Agreed about the 6X5 which is why I said most.

That said I think we can all agree it was primarily due to how zenith used the tube.


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 Post subject: Re: A new 300B amp project
PostPosted: Sep Wed 13, 2017 10:52 pm 
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I'm a REALITY guy.

When it comes to arguments over high cost "audio-grade" capacitors or SS vs tube rectification:

I say ... prove it.

Do a double-blind test.

Sit in front of your amp and while listening have someone switch the components in/out and then see if you audiophools can tell which rectifier is being used... or which coupling cap.
I say BS... lol.

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Wed 13, 2017 11:54 pm 
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Pbpix wrote:
I'm a REALITY guy.

When it comes to arguments over high cost "audio-grade" capacitors or SS vs tube rectification:

I say ... prove it.

Do a double-blind test.

Sit in front of your amp and while listening have someone switch the components in/out and then see if you audiophools can tell which rectifier is being used... or which coupling cap.
I say BS... lol.




Should this be done, before or after my glass of burgundy and slice of cheese?

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 2:07 am 
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Howdy John,

I say drink two bottles of wine, get really drunk, and munch on the cheese to sober up a bit while listening :D. That should do it, dude!

Man, I just thought of something else. If you guys don't use NOS paper-wax caps, NOS silver-mica caps (dominoes), NOS bumblebees, and NOS carbon resistors, and NOS sand resistors, this redesign/rebuild is going to be a sham! Remember, it has to be done old-school to treat the 300B correctly! :D

73,

Randy AB5NI

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 2:14 am 
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john8750 wrote:
Pbpix wrote:
I'm a REALITY guy.

When it comes to arguments over high cost "audio-grade" capacitors or SS vs tube rectification:

I say ... prove it.

Do a double-blind test.

Sit in front of your amp and while listening have someone switch the components in/out and then see if you audiophools can tell which rectifier is being used... or which coupling cap.
I say BS... lol.




Should this be done, before or after my glass of burgundy and slice of cheese?

Wait till ... just after you put on your tin-foil hat!

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To be a man, Be a non-conformist, Nothing's sacred as the integrity of your own mind.
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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 2:34 am 
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ab5ni wrote:
Howdy Flip,
You are incapable of moving into the 21st century, or even the 1970's, implying that solid state components have no business being in a tube amplifier. Man, if Peter was to have listened to this garbage, he would have never designed his 6V6/5902 amp which John enjoys very much, BTW.
73,

Randy AB5NI


Well .. I have to agree that even though Flip has lots of valuable help to contribute to these amplifier building projects, ( and we actually do appreciate that help) ... but yes, Randi you are quite right about his unwillingness to budge from his stodgy concepts at times.
I've had many debates with Flip about silicone in the audio power amp.
Flip says, he doesn't want ANY silicone to ever be in the audio path of his power tube amps. But I have to remind him that he feeds his tube amps from solid-state audio sources... so he has silicone in the audio-path anyway.. it's just a matter of where... earlier or later... but it's there.

When John finished his 5902 amp and was very pleased with it. Flip was claiming that the op-275 as the integrated pre-amp was just not up to what he felt a tube-based hifi audio power amp should be.
John an I argued with him trying to explain how beautiful it sounded. We asked Flip to reserve judgement until he himself could actually HEAR the sound of the 5902.
He disagreed.
So John and I offered to send Flip all the parts needed to build a 5902. Everything from tubes, op-amps, to iron.
We said we'd send him everything to build it because we valued his opinion on what it would sound like.
No matter how much we encouraged him and even to sending him free parts to build it just so he could hear it ( we were willing to make that investment to get his opinion of the sound)
But.. no matter what we offered... Flip politely declined.

So... it's kind of hard to get an educated opinion when someone decides they will refuse to even listen.
So... "you can lead a horse to water ... but you can't make him drink"
Image

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 2:42 am 
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Howdy Peter,

Pbpix wrote:
Wait till ... just after you put on your tin-foil hat!


Dude, I have designed the ultimate tin-foil hat that uses copper foil! Basically, take a cardboard box, line the inside and outside with copper foil, cut two holes out for each eye, use copper-mesh wire to cover the holes, and add stranded copper wire to each corner of the box, which can be plugged into the ground once stationary. The ground wires should also contain alligator clips to clip on to water pipes, AC receptacles, ground rods, or any other object that provides a good earth ground. Basically, at that point, the "hat" becomes a portable Faraday shield :D.

Hmmm. I just had another idea. You could also place a small pocket inside the box to hold your cell phone, making sure you aren't disturbed while listening to all the voices in your head! You could also listen to MP3s and such undisturbed as well.

Man, I think I'm going to build a prototype or two, ship one off to that dude that markets Oxiclean and that pillow of his, and see if he can make me really, really rich selling these things.

73,

Randy AB5NI

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 3:08 am 
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john8750 wrote:
I kinda like those Edcor,s painted black. What do you think?
download/file.php?id=189648
It's a matter of personal taste.

If you want to spruce up the amp get some VU meters. http://www.ebay.com/itm/500VU-Panel-VU- ... Sw241YXexn I got 'em when they were 2 bucks cheaper :mrgreen: You'll need a driver board because they're just a 'meter' with a VU face, but that's actually an advantage because they're scalable. http://www.ebay.com/itm/Dual-Stereo-VU- ... Sw44BYNWjU

The only problem is that means another transformer for the 12 V.


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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 3:10 am 
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Howdy Peter,

Oh, I know Flip means well, and he is a lot more knowledgeable about this stuff than we'll ever be, but some things in physics just can't be gotten around. Time marches on, better chemical dopants and compounds are discovered, and devices shrink and become more reliable. The shrinkage of electrolytics would be a good example here.

Personally, I think Flip is a good guy, and that is evident from him trying to help as he does! Kudos, Flip! He's just set in his ways and feels more comfortable using old-school technology. Not that this is a bad thing, mind you. The thing that we have to come to grips with is that Flip is an old-school purist, and the instant we try to pull him out of that comfort zone, he's going to balk. I think we'd all rather just say, "Okay, Flip, we get where you are coming from, and we'd all rather have your friendship, heed your advice and design concepts, and have you included in the group than see you throw your arms up in the air and walk away in disgust." We love you, Flip :D.

73,

Randy AB5NI

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 3:28 am 
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Pbpix wrote:
john8750 wrote:
Pbpix wrote:
I'm a REALITY guy.

When it comes to arguments over high cost "audio-grade" capacitors or SS vs tube rectification:

I say ... prove it.

Do a double-blind test.

Sit in front of your amp and while listening have someone switch the components in/out and then see if you audiophools can tell which rectifier is being used... or which coupling cap.
I say BS... lol.




Should this be done, before or after my glass of burgundy and slice of cheese?

Wait till ... just after you put on your tin-foil hat!


What do you mean about my tin-foil hat? I only put that on when watching Captain Video, Saturday nights.

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If I did something right, I made a mistake.


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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 5:03 am 
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Pbpix wrote:
Well .. I have to agree that even though Flip has lots of valuable help to contribute to these amplifier building projects, ( and we actually do appreciate that help) ... but yes, Randi you are quite right about his unwillingness to budge from his stodgy concepts at times....

Don't confuse "stodgy" with hobby. After working all my life with 'high tech' I build tube amps for amusement and the challenge of working with, as it's been called, "old school" technology.

If one wants to avail themselves of the 'latest tech', at least as far as a Class AB amp goes, then get a TDA7282 and be done with it.
Attachment:
tda7292-page1.png
tda7292-page1.png [ 68.33 KiB | Viewed 96 times ]


Not much of a challenge, is it?

I got into tubes because I had never worked with them before but any notion that I 'refuse to consider' solid state is laughably absurd. Anyone who's even passingly familiar with my designs know I have always used SS rectifiers, usually employ a MOSFET cap multiplier, and often use current mirrors for cathode bias under the output tubes, all for good reasons that I've expounded on before.

All this hogwash is simply because I said inrush protection isn't necessary, which it isn't.


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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 6:27 am 
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Flip:
Well I was remembering the following thread as a typical reply.
Do you remember it Flip?

----------------------------- 5902 Build by John ------------------------
http://www.antiqueradios.com/forums/vie ... &start=560


Pbpix wrote:
yeahh beau coup

This op275 boasts a Butler amp ... whatever that is.

"The OP275 is the first amplifier to feature the Butler Amplifier
front end. This new front end design combines both bipolar
and JFET transistors to attain amplifiers with the accuracy and
low noise performance of bipolar transistors, and the speed and
sound quality of JFETs"
---------------------------------------------
Flipperhome wrote:

Point is, it ain't a 'tube'.
That's just my personal preference.

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 8:09 am 
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Pbpix wrote:
Flip:
Well I was remembering the following thread as a typical reply.
Do you remember it Flip?

----------------------------- 5902 Build by John ------------------------
http://www.antiqueradios.com/forums/vie ... &start=560


Pbpix wrote:
yeahh beau coup

This op275 boasts a Butler amp ... whatever that is.

"The OP275 is the first amplifier to feature the Butler Amplifier
front end. This new front end design combines both bipolar
and JFET transistors to attain amplifiers with the accuracy and
low noise performance of bipolar transistors, and the speed and
sound quality of JFETs"
---------------------------------------------
Flipperhome wrote:

Point is, it ain't a 'tube'.
That's just my personal preference.
You have a very selective memory and are like a pet Yorkie that bites your pants leg and won't let go but should you manage to shake it loose just runs right back and bites it again.

I'm not going to relitigate the whole thing but, the fact is, an OP275 ain't a tube. "That's just my personal preference." So sue me.

In the letter to his son, by the person you originally copied the amp from, "I have always had a fascination with older technology. Being an Electrical Engineer, that means vacuum tubes. I have built many tube based projects. One that I am very proud of is a stereo amplifier that Peter and I built together. It was a classic design using a pair of 6V6GT output tubes per channel. Peter uses it every day as his main amplifier for his home theater system. "

OMG, he built a tube amp with tubes, and he's very proud of it. Knock me over with a feather.

He goes on "In order to keep the design small, I am using a hybrid design for the amplifier. A push-pull driver using a pair of opamps is used to drive a pair of 5902 output tubes for each channel. "

Well, that's a good reason.

"The system also needed a pair of small speakers to go along with the amplifier... The speakers have a low frequency point of about 120HZ."

So he built a "PC Speaker" system for his son. That's great. I've built a "PC Speaker" system too but, as any EE will tell you, put 10 EE's in a room, even with the same spec, and you'll get 10 different designs. Mine is housed in a 5x7 chassis and is all tube but "that's just my personal preference."

Attachment:
PC Speaker - Front Angle .jpg
PC Speaker - Front Angle .jpg [ 136.46 KiB | Viewed 89 times ]


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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 8:34 am 
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Howdy Flip,

Flip wrote:
So he built a "PC Speaker" system for his son. That's great. I've built a "PC Speaker" system too but, as any EE will tell you, put 10 EE's in a room, even with the same spec, and you'll get 10 different designs. Mine is housed in a 5x7 chassis and is all tube but "that's just my personal preference."


This is the reason why I came up with the "machine gun" method of design, Flip. We were all going to argue and complain about this or that anyway, so we might as well get it out in the open. The EE or programmer that came up with the best and highest number of innovative solutions got a $5K bonus check. 2nd place was $2.5K, and 3rd was $1000.00 and Friday off of work. It worked well :D.

One of my friends once told me that managing EE's and programmers was like trying to manage lightning or herd cats. I agreed with him. LOL!

73,

Randy AB5NI

P.S. During one of these sessions, I came up with this saying: "Hell to the power of not ever happening." :D. We all laughed our butts off and made many combos. You can just about imagine some of the more colorful combinations :D. "Hell to the power of NO WAY!" was quite popular, as was "Hell to the power of GO SCREW YOURSELF!" :D

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Last edited by ab5ni on Sep Thu 14, 2017 7:01 pm, edited 1 time in total.

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 1:37 pm 
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This is what I'm screaming: http://www.ti.com/product/LME49724 to be used in a hybrid.

73,

Randy AB5NI

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 6:58 pm 
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OK, my next amp.
download/file.php?id=189732
But, will need tone amp, and phono RIAA amp, and MP3 preamp. No tubes, no.
Forget it, I want tubes. Heck, anyone can buy a package class D amp for real cheap, but it just
wont be the same.

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 7:01 pm 
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ab5ni wrote:
This is what I'm screaming: http://www.ti.com/product/LME49724 to be used in a hybrid.

73,

Randy AB5NI



I like that also Randy. But for now, the more tubes, the better.

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 9:53 pm 
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Flip:
The only reason I posted your previous post as a reminder of your refusal to use SS in a tube amp was ... only because in your post directly above my reminder YOU had just stated this:
"any notion that I 'refuse to consider' solid state is laughably absurd."

So it seemed a bit of a gross contradiction.

(firstly i want to sincerely THANK you for all the technical help you DO provide because none of us are unappreciative of that)

But...
Flip... if you prefer to use ONLY tubes in YOUR amps... that is perfectly fine. Who cares?

But when we come to you ( like the ARF chief-tech guru) seeking helpful technical advice and/or opinions to help educate ourselves ... at that time, when you are dispensing your technical advice.... I would expect you to try to be a bit more objective about the application of SS in an amp and not simply poopoo any ideas about it because you don't personally use or like it.
You might, instead, want to just preface your technical advice by clearly stating your personal biases and non objective biases. Then when you add your true-technical advice we the reader, will be able to separate the factual-technical help from your personal non-objective choices.

Not here to bust your chops.. and we thank you for your help.
Just trying to keep things level so we know from where your advice comes. ok?

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 10:02 pm 
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Howdy John,

john8750 wrote:
ab5ni wrote:
This is what I'm screaming: http://www.ti.com/product/LME49724 to be used in a hybrid.

73,

Randy AB5NI



I like that also Randy. But for now, the more tubes, the better.


Sure, no problemo :D

73,

Randy AB5NI

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 Post subject: Re: A new 300B amp project
PostPosted: Sep Thu 14, 2017 10:06 pm 
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ab5ni wrote:
This is what I'm screaming: http://www.ti.com/product/LME49724 to be used in a hybrid.

73,

Randy AB5NI

The nice thing about the op-275 is that it uses up to a max of +/- 22v Vcc.
My 6V6 circuit uses +/-20v on the op-275.
With rails at that value it can DIRECTLY drive a final power tube's grid with as much as about 37vPP swing.

The lme49724 is +/- 15v w/a max of 18v

So I don't know enough about what tubes it might be able to drive directly.

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Last edited by Pbpix on Sep Fri 15, 2017 12:01 am, edited 1 time in total.

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