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December 01, 2020, 01:01:18 AM

Author Topic: More gain need with my DL-160  (Read 5394 times)

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Offline cmcdonnell

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More gain need with my DL-160
« on: December 05, 2009, 05:36:14 AM »
I have a Seduction with the upgrade kit (stock).  I have used it with a Denon DL-160 high output moving coil cartridge and a Foreplay 1 and things were fine.  I now have a Foreplay III (not upgrade yet, but soon) and I have to turn the preamp up to the last 2 clicks to get good volume.  The Foreplay III feeds Paramours.  At that setting there is pretty strong 60 cycle hum, but the sound is good.  I enjoy kits but I am not engineer.  Any help would be welcomed. 

Chuck

DL-160
Output:                1.6 mV
Impeadance:        160 ohms
Load Impedance:   More than 4.7 kohms

Offline Paul Joppa

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Re: More gain need with my DL-160
« Reply #1 on: December 05, 2009, 06:19:48 AM »
I think the first thing is to resolve the hum problem, which seems to be dependent on the volume control setting. If everything else is operating correctly, I would first suspect the turntable interconnects and ground wire. An just checking, all the components should be powered from the same outlet to minimize the chances of a ground loop.

There is nothing wrong with using the top few settings of the volume control, so you may have enough gain, unless I have misunderstood the situation. If you really do need more gain there are a few things you can do. First question is what version of the Paramour do you have? If it's an old one, does it have the C4S driver plate load modification?
Paul Joppa

Offline cmcdonnell

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Re: More gain need with my DL-160
« Reply #2 on: December 05, 2009, 04:19:28 PM »
When I use my cd player it the Foreplay III needs to be set at 10 to 11 o'clock.  The phono needs 3 o'clock.  The Paramours do have the CS4 upgrade.  They are dead quiet when you have the setting at 3 o'clock on CD inputs.  Should my seduction be without hum when the gain is set that high?  I just got a new cartridge (DL-160) after the first was damaged and could not be re-tipped.  I am going to put the Foreplay 1 back in place and try it.  I have not done so with this cartridge. 

15 minutes later.  I put a new power cord on the Seduction and no change.  Checked that pre and phone are in the same power strip.  Yes and still not change.  Tried moving phone to third input on Foreplay III, not change.  Unplugged CD player from Foreplay and all is quiet.  I will check on power for CD.  I think you helped me.  Thanks for your quick help on a Saturday.

Three final questions.  Does Bottlehead ever do shows in the midwest?  Chicago CES?  Is it worth it to upgrade the iron on the Paramours to Magnequest or should I just save up for Paramounts?

Chuck (in Iowa)

Thanks again.

Offline Paul Joppa

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Re: More gain need with my DL-160
« Reply #3 on: December 05, 2009, 05:52:38 PM »
Thanks, Chuck - lots of information in your last post.

From 11:00 to 3:00 is four steps, or 12dB. The difference between 1.6mV and 5mV (the design target for Seduction) is 10dB. So that's the deal - it's a fairly low output cartridge. Seduction was designed around 5mV cartridges, with an acceptable range of 2.5mV to 10mV. You can reduce the gain on the CD channel with larger resistors as described in the Foreplay III manual, and even increase the gain on the Seduction channel with a smaller resistor, as small as 15K will work.

The Seduction will not be entirely without hum when used with such a low output cartridge, but if I read between the lines correctly (it's always hard to interpret subjective observations!) there may be some other source of hum. See below. I don't think it should be as bad as you describe. Trying the older Foreplay might tell you something useful, so please report what you hear when you try that.

You said "Unplugged CD player from Foreplay and all is quiet. " - does that mean the phono operation is quieter with the CD disconnected? That strikes me as odd; such a situation would suggest there is a ground current problem with the CD player but the Foreplay III switches the grounds as well as the signal lines, specifically to break such potential ground current loops so it should not be the happening that way. If the CD player has a reversible power plug, try it both ways in the power strip or wall socket - that might tell us something useful. In some situations it helps to route all power cords close together (minimizing the loop area enclosed by the power cord ground or neutral wires). Hum is a shape-shifter, sometimes very hard to track down!

Dan (Doc B) will have to answer about shows; we have done more as part of the Tape Project than as Bottlehead lately, but have never been into shows or advertising or reviews.

If the Paramours produce enough power, and are low enough in hum, with your speakers, then I'd go for the Magnequest upgrade iron. The Paramount stock iron is pretty good if I do say so myself, but I still feel the Magnequest has the edge. If you want a bit more power (Paramount 300B is 8 watts) or a bit less amplifier hum (Paramount has DC filament supplies) that would be the way to go. The direct coupling in the 2A3 Paramount has an advantage comparable (in my opinion, YMMV) to the advantage of Magnequest iron. Of course, Paramount with Magnequest iron would be the best - but that's not the question you asked!
Paul Joppa

Offline Paul Joppa

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Re: More gain need with my DL-160
« Reply #4 on: December 05, 2009, 06:05:50 PM »
I probably should have mentioned a couple other options by now. I didn't because it seems quite possible there is another problem that can be solved so that more drastic measures won't be needed. But for the sake of completeness:

Eros has about 10dB more gain than Seduction, and works well with cartridges of lower output, I'd guess 1.2mV and up.

A step-up transformer (SUT) with a modest ratio would raise the DL-160 output. Any ratio greater than 1:3 would present a load to the cartridge of less than the manufacturer's recommended "4.7K or greater", and most SUTs have a ratio of 5 or 10. But not everyone agrees that the cartridge load should be a lot higher than the DC resistance (160 ohms). Some people prefer to match that resistance. The Peerless 15095 as an example is sometimes used in reverse as a SUT and has 150 and 600 ohm taps; it's designed for a 15K load on the high impedance winding which you can accomplish with a resistor. If it were me, I'd ask around on vinyl forums such as the Asylum one and see what other DL-160 owners have to say. If you match the impedance, the gain will drop in half so you want at least a 6:1 step-up ratio, and 10:1 would still work pretty well.

Both of these ideas will rais the cartridge sensitivity, but if that is not the only hum-related problem they won't help that aspect. Just a caution.
Paul Joppa

Offline cmcdonnell

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Re: More gain need with my DL-160
« Reply #5 on: December 06, 2009, 02:33:02 PM »
Thanks again for all you ideas and help.  You are correct that the hum is virtually eliminated when the CD player is disconnected.  The CD player is my weakest link.  I do have an Oppo on another system and I will be trying that next week.  I did add resistance to my original Foreplay for the CD and was pretty well balanced.  Most of the time with that system I used the DL cartridge, Seduction, Foreplay 1, Accuphase 40 watt class A, and Magepan 1.6 speakers.  To say I didn

Offline Wanderer

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Re: More gain need with my DL-160
« Reply #6 on: December 06, 2009, 03:24:33 PM »
Several sources, Jerry Rashin at Needle Doctor is one, state the output of the Denon 110/160 is higher than 2 mV and not as low as the 1.6 the manufacturer specs state.

I built a bone stock Seduction for a non-diy buddy of mine. Seems to give healthy output from the Denon 110 he uses.  He gets VERY low hum and I had VERY little hum here when I broke it in with my then current Grado Blue. I tempted to say "no hum" but there was the VERY minor hum I expect from any phono circuit, well below any noise produced by vinyl playback. 

If you are getting an audible hum I am thinking PJ is quite correct to suggest there is some other issue than just the gain of the Seduction. Perhaps there is a miswire somewhere causing a ground loop?     
   
Kevin R-M

Offline cmcdonnell

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Re: More gain need with my DL-160
« Reply #7 on: December 06, 2009, 04:37:23 PM »
The hum is well below the vinyl noise when the CD is disconnected.  I will be working on that.  I don't think the Seduction is the problem either.  Thanks.

Offline Grainger49

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Re: More gain need with my DL-160
« Reply #8 on: December 07, 2009, 09:41:55 AM »
Chuck,

PJ is too modest.  The additional gain is not the only thing that the Eros has over the Seduction.  I own a Seduction.  I wrote a mini review of the Eros that Doc included in his recent auction of an assembled Eros:

http://db.audioasylum.com/cgi/m.mpl?forum=bottlehead&n=137203

You seem to have located much of your hum in the CD player.  If there is any hum that remains try as PJ suggested checking the connections from the TT to Seduction and Seduction to Foreplay.  Try cleaning everything from the cartridge clips to FP input jack.  You are dealing with tiny signal levels here.  Also try removing and reseating the tubes a couple of times.  The tube pins might have some oxidation on them.

Enjoy!
« Last Edit: January 01, 2010, 05:10:49 AM by Grainger49 »

Offline cmcdonnell

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Re: More gain need with my DL-160
« Reply #9 on: December 07, 2009, 02:57:42 PM »
PJ
I told you earlier that I did get the Foreplay III on Ebay and purchased the upgrade kit (not installed yet)from you.  I checked the resistors on the selector switch and low and behold there are three different pairs of resistors in place.  All measure 80K and change.  One is the same size as your instruction photo and installed with no lead on the selector switch and the other three are much larger resistor and mounted in the middle with the same length lead on both sides.  I do feel that 80K is about right for my CD player, but this explains the seemingly low output from my seduction.  I will be ordering correct resistors soon.  Is there a best choice resistor?

Chuck

Offline Paul Joppa

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Re: More gain need with my DL-160
« Reply #10 on: December 07, 2009, 05:59:11 PM »
Great to hear - you can get 6dB (two clicks) more gain for the Seduction with 33K resistors.

"Best" is a slippery concept. I like the (Vishay/)Dale RN series - quality metal film with copper leads. There are many other favorites - you'll probably get some posts about them ... in this location, they do not carry DC which opens the field to a wider variety of choices. I'd stay away from carbon composition unless you know you have some high quality ones that are truly sealed, because moisture can cause them to drift in value as they age. And I can't find anybody who admires metal oxide resistors in signal applications, though they are quite rugged and useful in power supplies.
Paul Joppa

Offline Grainger49

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Re: More gain need with my DL-160
« Reply #11 on: December 08, 2009, 12:29:30 AM »
Chuck,

I think that Radio Shack still sells some resistor packages.  The back of the package used to list the values that are included.  These are metal film but not the Vishay/Dale that PJ mentions.  But this pack will probably get you going quickly.  And it is always nice to have an assortment of resistors available.

Enjoy!

Offline Muimui

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Re: More gain need with my DL-160
« Reply #12 on: November 01, 2017, 06:39:24 PM »
Hello everybody
I built the Seduction many years ago and lately used it in my system.  The volume output is a little low.  Paul Joppa in post 4565 wrote:  “increase the gain of the Seduction with smaller resistor,as small as 15k will work”.  I have misplaced my manual.  Which resistors to replace?  Pictures and detail instructions is greatly appreciated.  A 5 to 10db increase would be nice.
Thanks
Larry

Offline BNAL

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Re: More gain need with my DL-160
« Reply #13 on: November 02, 2017, 03:26:10 AM »
I believe Paul is talking about the resistors on the Foreplay III input and not on the Seduction.
Brad Nalitt
Iron Upgraded S.E.X. Amp 2.0
Foreplay III
Quickie w/PJCCS
Eros Phono
Blumenstein Orca Speakers, Baby Benthic Subs
S.E.X.y Speakers W/FT17H Horn Tweeters
Thorens TD 125 MkII W/ Shure M97xE JICO SAS Stylus

Offline Paul Birkeland

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Re: More gain need with my DL-160
« Reply #14 on: November 02, 2017, 04:11:37 AM »
Hello everybody
I built the Seduction many years ago and lately used it in my system.  The volume output is a little low.  Paul Joppa in post 4565 wrote:  “increase the gain of the Seduction with smaller resistor,as small as 15k will work”.  I have misplaced my manual.  Which resistors to replace?  Pictures and detail instructions is greatly appreciated.  A 5 to 10db increase would be nice.
Thanks
Larry
To increase the gain in the Seduction, you would want to add C4S loads in place of the plate load resistors.

There are no other parts you can swap out for more gain.  (We would have done that in the original kit)

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man