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Old 15th November 2004, 03:00 PM   #501
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Hi peranders,

Quote:
Originally posted by peranders
... Beware of cross conduction!
I am not sure I follow you here.

My understanding is that cross conduction is where one device doesn't turn off fast enough and the complimentry device is still active and they then fight between themselves against the opposite power rails?

???

Best wishes,
Susan.
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Old 15th November 2004, 03:05 PM   #502
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Default Re: Re: Re: Confirmation on Affirmation

Quote:
Originally posted by peranders

... or 735.5 Watts if it's a metric one
Either way it's a lot of power and standing on the ground looking up at the beasts I just SO know that there is a lot going on between those ears and if I do get to ride the thing it is only on it's sufference.

Best wishes,
Susan.

Currently listening to maybe 0.0015 of a horse.
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Old 15th November 2004, 03:06 PM   #503
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Arrow Commentable Experienced Thoughts

Hi SUSAN-PARKER

We Will Use VCC at 60VDC
Force air cooling
No source reistors
load impedance at 2 Ohms

regards
workhorse technologies
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Old 15th November 2004, 03:18 PM   #504
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Default Re: Commentable Experienced Thoughts

Hi Amp_man,

Quote:
Originally posted by amp_man_1
Hi SUSAN-PARKER

We Will Use VCC at 60VDC
Force air cooling
No source reistors
load impedance at 2 Ohms

regards
workhorse technologies
Assuming you are using a proper 2:1 output transformer and not the center tapped inductor version I make that on the order of 741.125 watts.

Force air cooling - very good

Quiescent bias level set for about an amp total?

Exciting.

Thanks.

Best wishes,
Susan.
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Old 15th November 2004, 03:18 PM   #505
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Arrow Re: Re: Re: Confirmation on Affirmation

Quote:
Originally posted by peranders

... or 735.5 Watts if it's a metric one

PLZ DONT Worry P-E-R-A-N-D-E-R-S The Moderator[good title]

we are professional power people So 750W is just a bit of little exercise for us, no hard Schedule indeed.

Hope u understand
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Old 15th November 2004, 09:25 PM   #506
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Default Bass Speaker Drawings

Dear All,

For anyone who is interested about the delivery end of all this I have updated my bass speaker page and added 150 dpi resolution B/W drawings for printing (as requested).

http://www.susan-parker.co.uk/susan-speaker-bass.htm

There is also a link to the driver manufacturer's web site.

Only rated at about one foal though.

Best wishes,
Susan.
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Old 16th November 2004, 11:30 AM   #507
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Default IC Balanced Line Driver Input

Dear All,

Here are pics of the two stage amplifier driven using a SSM2142 Balanced Line Driver instead of the first transformer to drive the first stage mosfet gates.

Click the image to open in full size.

http://www.susan-parker.co.uk/zeus-2...42-drive-1.jpg

Full pic of the whole amp:

http://www.susan-parker.co.uk/zeus-2...142-full-1.jpg

The SSM2142's GND input pin 3 is referenced to Vbias as is the Input pin 4 which has a 100k resistor to pin 3. The input signal is capacitively coupled to allow for the shift in levels.

Gain stage on this test board is a SSM2015, with 2 x 10uF input cap mixing down of stereo to mono for testing.

This should also work with the DRV134 parts as they look to be the same configuration (and same pin numbers).

Best wishes,
Susan.
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Old 16th November 2004, 04:01 PM   #508
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Default Re: A little more transformer info....

Quote:
Originally posted by Susan-Parker
Okay just to confirm that's 124 UKP or $232 US for two transformers and shipping?
Yep, here's what Sowter's sales rep emailed:

Quote:
Dear Victor,

The price with carriage will be:
1 pcs type 8160 @ UKP 47.75 each = UKP 47.75
carriage and packing - Airsure = UKP 14.50

Total UKP 62.25

For 2 pcs the total price will be UKP 124.50

The lead time at the moment is 2-3 weeks from receipt of your
order and credit card details.

Best regards,
Ruth.
Quote:
Originally posted by Susan-Parker
EI's are also more flexible in the choice of lamination materials and build up strategies. Note: If given a choice of lamination thicknesses for a given stack size, go for the thinner ones. A little more fiddly to assemble but will have better theoretical performance.
Thomas & Skinner has three thicknesses of M-6 Orthosil laminations - 004", .006" and .014" or for those in the metric world - 0.1016mm , 0.1524mm, and 0.3556mm

How tough do you think it would be to work with the two thinnest lams? They sound almost like tissue paper to me.

Quote:
Note that for these sensitivity ratings you should run the transformer as 2:1 not just across the arms to get lower distortion.

And if you wind the toroid in for example two sections matched then for your sensitivity speakers you could also try 4:1 which will really bring the distortion levels down.
I don't quite follow the "running" the transformers at 2:1 or 4:1 part. Does that refer to the winding ratio?

On the 200VA toroid you suggest a single "Quad-filar wind of 0.8 mm enameled magnet wire w/ 120 to 150 turns." But, on the E-I, there are primary and secondary windings.

Could you please clarify this for little ol' me? I'm a bit confused.
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Old 16th November 2004, 05:32 PM   #509
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Default Re: IC Balanced Line Driver Input

Quote:
Originally posted by Susan-Parker
Here are pics of the two stage amplifier driven using a SSM2142 Balanced Line Driver instead of the first transformer to drive the first stage mosfet gates
Very nice. More importantly, very cheap

How does it sound compared to using an input transformer?

You stated in an earlier post that:

Quote:
In case anyone was wondering I did test out the SSM2142 and regretfully (as I have a full tube of the things) that gets the thumbs down as far as transformer input stage driving goes.
Was that because of too much gain? input trans (1:10) + 6 dB from the SSM2142.

Or, was that a matter of just sounding terrible?

Quote:
Gain stage on this test board is a SSM2015, with 2 x 10uF input cap mixing down of stereo to mono for testing.
How does it work gain-wise? The input trans you've been using are 1:9 or 1:10, the SSM2142/SSM2015 combo is 21dB, I think (1:5?).

The SSM2142 provides 6dB gain. I can't find a datasheet for the SSM2015 anywhere, including AD. But, it is mentioned in the SSM2402/
SSM2412 datasheet
(pg. 9, Fig 7) as being set to a gain of 15dB.

Quote:
The SSM2015 is set to produce a
15 dB gain. The signal drive level into the SSM2402 switch is
then +10 dBu with a +20 dBu input level and +14 dBu peak,
well within ideal operating range.
It's too bad the balanced line receivers I've seen so far(INA134/137, SSM2015) convert the differential single back to single-ended. It would be great to use the Pro Audio approach of a line amplifier at the preamp and receiver in the Zeus in lieu of the input tranformer.

We'd get all the advantages of noise rejection and the ability to drive any length cables with extremely low distortion.

Do you think it would be possible to feed the + and - differential signals to seperate receivers in the INA2137 dual receiver pictured below and still maintain balance?
Click the image to open in full size.

The + input for both receivers would share the common ground line of the differential cable.

Anyway, just a thought.
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Old 17th November 2004, 10:29 AM   #510
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Default Re: Re: A little more transformer info....

Hi Darkmoebius

Quote:
Originally posted by darkmoebius

Yep, here's what Sowter's sales rep emailed:
Ah, great. Thanks for that confirmation.

Quote:
Thomas & Skinner has three thicknesses of M-6 Orthosil laminations - 004", .006" and .014" or for those in the metric world - 0.1016mm , 0.1524mm, and 0.3556mm

How tough do you think it would be to work with the two thinnest lams? They sound almost like tissue paper to me.
The M6 I have been using is the 0.35 mm / 0.014" thickness material.

These thinner laminations I would call it shim, but yes it is getting down to tissue paper thickness.

The 0.006" / 0.15 mm is the best compromise between manageability and at under half the thickness of the standard laminations should give much improved theoretical magnetization curves. Going to the even finer laminations is only a third thinner than this, and probably not worth the extra hassle.

These laminations can be very sharp and care should be taken when handling not to get the equivalent of paper cuts (how do I know this?). I would recommend wearing light cotton gloves to keep the individual laminations as clean as possible.

Remember when assembling the frames/shrouds to go round the bolts a few times sequentially tightening as you want the stack well compressed (the same as tightening the wheel bolts on a car after changing a wheel).

I can't say that it is necessarily going to be that audible or easy to measure the differences without very careful A/B comparisons as there are so many factors influencing the final sound quality.

But for the additional effort of building these transformers oneself one might as well be happy that one has the best configuration.

FYI I am intending to switch over to using the 0.006" / 0.15 mm laminations once I have used up my current stock.

Quote:
I don't quite follow the "running" the transformers at 2:1 or 4:1 part. Does that refer to the winding ratio?

On the 200VA toroid you suggest a single "Quad-filar wind of 0.8 mm enameled magnet wire w/ 120 to 150 turns." But, on the E-I, there are primary and secondary windings.

Could you please clarify this for little ol' me? I'm a bit confused. [/B]
Okay.

Example 1:

If you use a power mains toroid transformer with bifilar wound secondaries and, using these secondaries only, wire the speaker directly across the windings you have a 1:1 coupling from the voltage across the mosfet's sources to the speaker.

Example 2:

If you quad filar wind the transformer then take two windings and wire them in series with the center grounded and the two out of phase ends to the mosfet's sources, then wire the other two separately in parallel for the speaker, you have a 2:1 step down transformer.

Example 3:

Quad filar wind the transformer as before, but split two of the windings half way.

Take the two full windings and wire them in series with the center grounded and the two out of phase ends to the mosfet's sources.

Wire the other two sets of four windings into two pairs of parallel windings and connect to a switch.

Set the switch to series for the speaker you have a 2:1 step down transformer, set the switch to parallel for the speaker you have a 4:1 step down transformer.

==

For the 75 watt transformer (new spec N size that Sowter will be making) in standard transformer configuration there are four output windings and one could bring them out to an 8 way Neutrik Speakon style connector for maximum flexibility. Then it is just a plug wiring configuration.

For a hard wired configuration the Multi-Contact 2 Powerline 6mm series looks interesting as an alternative for higher powers and larger cable diameters.

http://www.multi-contact.com/

"Round Connectors, up to 600V, up to 125A, 6mm, single-pole, insulated."

I have a set of these which are going to be used in my bass driver amp.

Model ID/B6AR-N-S safety panel receptacles (sockets - chassis mount with bolt cable fixing).
14.0010-21
14.0010-22

http://www.multi-contact.com/Product...D_B6AR-N-S.gif

Model KST6AR-N/... plugs
15.5001-21
15.5001-22

http://www.multi-contact.com/Product...ST6AR-N_10.gif

=====

The reason for having these options (Example 3) is to better match the loudspeaker load to the amplifier output.

From the previously posted distortion figures one can see that distortion rises as the load is decreased in impedance (I will be adding these to my website shortly).

By switching around the four output windings one can match to the get better distortion characteristics.

Going from 2:1 to 4:1 step down ratios will reduce the distortion figures for the same load impedance - I have measured down to a quarter going from 8 to 16 ohms.

Obviously the amount of power is reduced but this is part of the trade off.


I hope this helps.

Best wishes,
Susan.
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