Search found 1570 matches

by dave slagle
Fri Sep 23, 2022 1:32 am
Forum: Phono
Topic: High Impedance cartridges and SUT's
Replies: 6
Views: 215

Re: High Impedance cartridges and SUT's

The difference between 12 and 15 on the step up is only 2dB so for the most part I would consider them interchangeable.

dave
by dave slagle
Thu Sep 22, 2022 12:19 am
Forum: Phono
Topic: High Impedance cartridges and SUT's
Replies: 6
Views: 215

Re: High Impedance cartridges and SUT's

right.... and from the perspective of the SUT it is being driven from a 2Ω source or 3X the published 0.6Ω. I used to do SUT's specific to the sub 1Ω carts until I realized that the tonearm DCR has a dominant effect on the situation.
dave
by dave slagle
Wed Sep 21, 2022 12:17 am
Forum: Phono
Topic: High Impedance cartridges and SUT's
Replies: 6
Views: 215

Re: High Impedance cartridges and SUT's

The achilles heel of a 0.6Ω cartridge is the tonearm wiring is often double that value effectively turning it into a 2Ω cartridge.

I would confirm the tonearm DCR prior to committing to a design.

dave
by dave slagle
Sun Sep 04, 2022 1:19 pm
Forum: Attenuators
Topic: Autoformer modules q re second (fine adjustment) switch
Replies: 4
Views: 127

Re: Autoformer modules q re second (fine adjustment) switch

yes...

I might still have some boards for them though. send me a private email.

dave
by dave slagle
Sun Sep 04, 2022 12:09 am
Forum: Attenuators
Topic: Autoformer modules q re second (fine adjustment) switch
Replies: 4
Views: 127

Re: Autoformer modules q re second (fine adjustment) switch

Hey.

The modules attenuate completely by selection of taps on the autoformers. I see adding an additional resistive attenuation as a liability rather than an asset.

dave
by dave slagle
Sun Aug 07, 2022 8:35 pm
Forum: Playing With Airgaps
Topic: Restacking lams of speakerformers
Replies: 3
Views: 164

Re: Restacking lams of speakerformers

it simply comes down to inductance. if you have an excess then increasing the gap is worth a try.

dave
by dave slagle
Thu Jul 28, 2022 3:20 pm
Forum: Phono
Topic: High Impedance cartridges and SUT's
Replies: 6
Views: 215

High Impedance cartridges and SUT's

I have noticed a trend lately of people asking for high ratio SUTs for higher impedance cartridges. The current request was for a 1:50 for a 22Ω cartridge and the following is why I think that is a bad idea. There are two different places where you can get into trouble here and they both have to do ...
by dave slagle
Mon Jul 18, 2022 11:59 am
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

At this point I think it is probably best to take the unit back to stock and make sure it operates noise free when used single ended.

dave
by dave slagle
Sun Jul 17, 2022 12:31 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

Pins 5,7,8 go to ground.... I cannot use specific ground terminology since I did not design or build the circuit. The negative outputs that were tied to pins 5 & 7 have B+ on them so shoring them to ground is not a good move. I think we may have gotten way off point here and without me being int...
by dave slagle
Sat Jul 16, 2022 11:14 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

5, 7 & 8 all can tie together and go to signal ground.
by dave slagle
Sat Jul 16, 2022 9:21 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

the shield appears to be pin 8 from the diagram

dave
by dave slagle
Sat Jul 16, 2022 12:21 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

Tha autoformers and transformer secondaries should attach to the same ground as the RCA jacks and the signal tubes which appears to be "ref" for the balanced circuit. Ultimately they will all tie together at some point and the goal is to connect them in the manner that gives the least nois...
by dave slagle
Fri Jul 15, 2022 11:54 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

than needs to be tied to audio ground at some point.

dave
by dave slagle
Fri Jul 15, 2022 8:29 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

central tap???

you mean the junction of pins 1 & 3 on the 1674?

dave
by dave slagle
Fri Jul 15, 2022 12:32 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

did you also reference the secondary of the 1674 to ground?

It is unclear what the large cap is.... there is nothing power supply related on the output board. Only the parafeed cap and the mute circuit.
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by dave slagle
Tue Jul 12, 2022 6:11 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

they should be interchangeable the autoformer just has a single ground wire and the TVC has two (primary and secondary) which are connected together.


dave
by dave slagle
Sun Jul 10, 2022 12:12 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

that depends on the preamp design and ultimately the signal levels involved. The 6H30 has a mu of 15 so call it a gain of 3.75 after the stepdown. Feed it with 2V in and you net a meax of 7.5V out which is fine for the autoformers. Feed it with 4V and you might start to run into low frequency overlo...
by dave slagle
Thu Jun 30, 2022 11:44 am
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

The pinout of the transformer appears to match the datasheet. the only difference is one is mirrored from the other 1:4 in the spec sheet and 4:1 in the schematic. It looks to me like the connections you need to change are at the input and output of the board so no traces should need to be cut. dave
by dave slagle
Wed Jun 29, 2022 2:44 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

ugh... slicing traces gets interesting... it looks like the 1674's are on their own boards with yellow wires to connect to the main board.

where is the 680nF 'parafeeed cap'

dave
by dave slagle
Wed Jun 29, 2022 12:30 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

The 1674 appears to be a 1+1:4+4 that is being used as a 4+4:1+1 so the mirror image of the spec sheet matches the schematic above.

dave
by dave slagle
Tue Jun 28, 2022 1:27 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

I now see the TVC's and they are early versions prior to john working with me so they may have been doing the SE>>balanced conversion at the input. To test for proper function I would put a SE signal between L+ and "ref" and groundL- to Ref. Then on the LL1674 disconnect pin 7 from L- and ...
by dave slagle
Mon Jun 27, 2022 2:12 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

Since John mentioned you needed 4 "TVC" units I suspect they were not TVCs but my autoformers. The original bent units used S&B TVC's which could fo bal>>SE and SE>>bal connections (albeit not very well). Your autoformers are ready to ship but I want to hold off until I am sure things ...
by dave slagle
Sun Jun 26, 2022 7:22 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

does it function ow SE in Se out without the TVC?

dave
by dave slagle
Sun Jun 26, 2022 12:14 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

No on grounding the - of a balanced signal. Does the unit have the LL 1764 on it? that can be configured for SE output. As for the input that gets a little more interesting... How is the input currently handled? It looks like you could simply use 1/2 of the entire circuit SE so that may be what is b...
by dave slagle
Sat Jun 25, 2022 10:38 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

Hey,

The schematics are of a balanced input / output circuit. How do you plan on using it SE?
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by dave slagle
Sat Jun 25, 2022 12:38 pm
Forum: Circuits
Topic: When and where to ground
Replies: 54
Views: 1894

Re: When and where to ground

Do you have a schematic of the active board?

dave
by dave slagle
Sun Jun 12, 2022 8:49 pm
Forum: Your name here.
Topic: moe pics
Replies: 63
Views: 23288

Re: moe pics

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by dave slagle
Sun Jun 12, 2022 1:23 pm
Forum: Your name here.
Topic: moe pics
Replies: 63
Views: 23288

Re: moe pics

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by dave slagle
Tue May 10, 2022 1:01 pm
Forum: Your name here.
Topic: moe pics
Replies: 63
Views: 23288

Re: moe pics

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by dave slagle
Sat May 07, 2022 1:00 pm
Forum: Your name here.
Topic: moe pics
Replies: 63
Views: 23288

Re: moe pics

77
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