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AudioRoundTable.com: Thermionic Emissions => Super simple linestage.

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Of course... [message #9147 is a reply to message #9145 ] Thu, 04 August 2005 16:20 Go to previous messageGo to next message
Damir  is currently offline Damir
Messages: 1005
Registered: May 2009
Illuminati (2nd Degree)
...that`s why we build our gear with DN2540N5 tubes...

Dear Mr. Kut... [message #9148 is a reply to message #9145 ] Thu, 04 August 2005 16:37 Go to previous messageGo to next message
Thrint  is currently offline Thrint
Messages: 43
Registered: May 2009
Baron
I don't think it was spam. The same circuit can be done with valves or SS. Like I said, I built the circuit which lead to this with valves. I have designed some stuff which was quite well recieved in these parts with a mix of SS and valves( Guinevere and Merlin ).

Is there anything else you'd care to take issue with? There is plenty of SS in both of those designs, BTW.
regards,
Douglas

Re: Super simple linestage. [message #9149 is a reply to message #9143 ] Thu, 04 August 2005 16:44 Go to previous messageGo to next message
Thrint  is currently offline Thrint
Messages: 43
Registered: May 2009
Baron
Which would you perfer?

The valve circuit can be done with a +/- 200V supply fairly easily with cheap valves.

For the input circuit, a triode strapped 6EJ7 and a pentode rigged 6EJ7 would be great. ~$3/tube too

Now for the CCS for this cascoded cathode follower to work into. Single pentode perhaps? 6CL6 or an EL84 or any of the similar sized 9-pin pentodes would do. One could get nuts with a regulated g2 supply, but a dropping R and bypass C would be quite good as well.

The beauty of the MOSFET sol'n is that we could do it with +/- 30V and DN2540N5's. Or a -30 supply with a MOSFET cathode load and valves on top. This I am going to build soon. I have a request from a very good friend back in PA for just such an item. I think I'll do it with Intact Audio ( Dave Slagle ) Autoformer volume controls if he'll foot the bill...
regards,
Douglas


Re: Super simple linestage. [message #9151 is a reply to message #9149 ] Sat, 06 August 2005 14:42 Go to previous messageGo to next message
metasonix  is currently offline metasonix
Messages: 103
Registered: May 2009
Viscount
I vote for transistor--seen too many tube variations on this.

Mine too... [message #9152 is a reply to message #9151 ] Sun, 07 August 2005 19:34 Go to previous messageGo to next message
Thrint  is currently offline Thrint
Messages: 43
Registered: May 2009
Baron
Went through the shelf of Iron and parts:
1.5A/54.5-0-54.5 volt power TX. Full bridge, CT grounded
2x 15 Hy/75 mA Hammond chokes( mmmmmmhhhh, matched pair! )
coffee tin of 120 uF photo flash caps
50k, Audio taper Noble pot
Sleeve of DN2540N5 Mosfet's
6 uF/220VAC Vit-Q AC caps for output coupling.

The PS will yeild about +/- 40V. I think I'll try a 10 mA idle current for less than 1/2 Watt dissipation per top MOSFET and run w/o heatsinks.

I have everything but the plate to mount to. Looks like a nice simple job at this time now. I can't wait to get it underway so I can put it In-System and see how it compares to the All-Valve version.

See anything I missed? Diodes? Anybody have some nice diodes? 200 PIV/2A Schottkey?

mmmhhhhh, no heaters!
regards,
Douglas

Re: Dear Mr. Kut... [message #9153 is a reply to message #9148 ] Mon, 08 August 2005 14:16 Go to previous messageGo to next message
Rek_O_Kut  is currently offline Rek_O_Kut
Messages: 4
Registered: May 2009
Esquire
>The same circuit can be done with valves or SS.

That's true of most fundamental concepts, but entirely irrelevant. Solid-state designs are inappropriate to this forum.

Can you explain... [message #9154 is a reply to message #9153 ] Mon, 08 August 2005 15:14 Go to previous messageGo to next message
Damir  is currently offline Damir
Messages: 1005
Registered: May 2009
Illuminati (2nd Degree)
...what % of some design/amp can be SS, if any? I must confess that I used SS diodes sometimes, even IC voltage regulators, some transistor here and there (CCS)... But, the worst sin I`ve ever done was the guitar amp, entirely SS. Preamp 741 op-amps, then 5-band graphic EQ with about 7 other evil op-amps, and output stage with STK025 IC. Even PS for the preamp & EQ was transistors regulated, +/- 10V, BC141/BC161...
Then 10-band VU-meter with LEDs, I don`t remember what IC...
Sorry, I was young - it happened almost 25 years ago...
Anyway, I`m glad that I had a chance to confess it here, bye...

Re: Dear Mr. Kut... [message #9156 is a reply to message #9153 ] Mon, 08 August 2005 16:28 Go to previous messageGo to next message
Thrint  is currently offline Thrint
Messages: 43
Registered: May 2009
Baron
>>>That's true of most fundamental concepts, but entirely irrelevant. Solid-state designs are inappropriate to this forum.

Well, you're entirely entitled to your opinion, no matter hwo wrong it appears to me.

So where do you draw the line for being Tube PC( assuming that the term is even valid ).
regards,
Douglas


It's not a tube design if it doesn't have any tubes [message #9157 is a reply to message #9156 ] Mon, 08 August 2005 21:36 Go to previous messageGo to next message
Rek_O_Kut  is currently offline Rek_O_Kut
Messages: 4
Registered: May 2009
Esquire
Which is again why your design info belongs elsewhere.

mandatory change [message #9158 is a reply to message #9157 ] Tue, 09 August 2005 04:34 Go to previous messageGo to previous message
Thrint  is currently offline Thrint
Messages: 43
Registered: May 2009
Baron
*NOT*....

but a +/- 40 volt power suply can be done with a vacuum rectifier diode. A pair of 6AX6 will do nicely. There's another from the Hy-G-300 Red Bank series in 9-pin for building a full wave bridge, the 6754.
regards,
Douglas

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