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Old 23rd Feb 2020, 3:45 pm   #1
khanrahan
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Question DUAL CS505-2 too quiet

Hello - first time poster here but I've learned a lot on this site recently. Such a great community!

Anyway my question. I recently set about getting my fathers DUAL CS505-2 back in working order. Upon some careful inspection I noticed that the phono plugs had taken a bit of a banging at the actual plugs - but they seem okay. I then noticed that both belts needed replacing. I used an excellent post on this site to guide me through that issue. After that I had a switch problem inside the turntable. Basically when the arm moved, it did not turn on the motor. An excellent youtube video and some patience helped me to solve that. Turned out it was a build up of grime on a pin - so I just had to clean it and re-lubricate it.

After I had completed those repairs I tried to connect it to me Amplifier. I use a SONY LBT-V701 Stereo Integrated Amplifier. I connected via the phono connection on the back and popped on a record. I can hear it coming through the speakers - but only very slightly. I tested another player I have (a much cheaper SONY PS-LX250H) - and this played fine - great volume.

I'm now wondering is there an amplification incompatibility, or is there a phono cable issue, or is there a needle issue? I'm really sort of at a dead end. I'm trying to get this turntable in working order by myself rather than handing it in to some repair shop as I want to learn more about how these work. I've a very healthy collection of vinyl but a very unhealthy knowledge of how the tech works!

Any advice from you guys would be very helpful.

I should also point out I've never soldered before - in case that might be needed here. But I guess I could learn!

Thank you in advice for taking the time to read this. It's been a lot of fun bringing this back to life - and I'm not ready to give up now that I've got the belts on and the motor running!

Thanks!!
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Old 23rd Feb 2020, 3:57 pm   #2
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Default Re: DUAL CS505-2 too quiet

Although that amp does have a 'phono input', many amps of that era don't have a proper RIAA preamp for a magnetic cartridge as most people were using CDs by then. It sounds as if your amp is like that. If so, you will need to use an external preamp. There's no need to spend a lot of money on this - you can buy them from eBay sellers for less than €20. They are also easy to build.

Example: https://www.ebay.co.uk/itm/PHONO-PRE...H/392348401516
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Old 23rd Feb 2020, 4:07 pm   #3
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Default Re: DUAL CS505-2 too quiet

I think the LBT-701 is part of a 'component system' so the phone input may not be for an MM cartridge. What you would need is a phono pre-amplifier.
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Old 23rd Feb 2020, 4:36 pm   #4
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Default Re: DUAL CS505-2 too quiet

Thanks for the information Paul and PJL! I really appreciate that. I've got a decent amazon gift card put aside so I'll take a look on amazon now for a Phono Pre Amp! You guys are a big help. Thanks. I'll report back to the thread once I test this out.
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Old 23rd Feb 2020, 5:20 pm   #5
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Default Re: DUAL CS505-2 too quiet

Your Sony PS-LX250H turntable has a built-in pre-amplifier, that's why it will play at the correct volume level on your Sony stereo amplifier.
Now, you will need a MM Phono Pre-amp. Don't skimp on these, best to buy a good NAD or PROJECT unit for abut £40-00- and that's very cheap for a pre-amp. They will come with a dedicated power supply. You will not regret it.
For your future reference, styli ("needle"), will very rarely affect the "loudness" of a record deck.
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Old 23rd Feb 2020, 5:23 pm   #6
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Default Re: DUAL CS505-2 too quiet

Hi i think the amp is part of a system if memory serves right it used the ps-v701 turntable this used a Audio Technica cart type AT 91e, this cart is a magnetic cart this from the sm for the deck cant find sm for amp Mick
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Old 23rd Feb 2020, 5:44 pm   #7
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Default Re: DUAL CS505-2 too quiet

Quote:
Originally Posted by Edward Huggins View Post
Your Sony PS-LX250H turntable has a built-in pre-amplifier, that's why it will play at the correct volume level on your Sony stereo amplifier.
Now, you will need a MM Phono Pre-amp. Don't skimp on these, best to buy a good NAD or PROJECT unit for abut £40-00- and that's very cheap for a pre-amp. They will come with a dedicated power supply. You will not regret it.
For your future reference, styli ("needle"), will very rarely affect the "loudness" of a record deck.
Although there's no harm in buying a branded hifi preamp, it's unlikely to make much difference with this setup. They're all basically the same at this end of the market - just a TL072 class dual op-amp plus a few resistors and caps. You can run them from a 9V battery if you like, which will provide very clean power and last for months if you remember to switch it off.
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Old 23rd Feb 2020, 9:03 pm   #8
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Default Re: DUAL CS505-2 too quiet

Thanks for the thoughts everyone. I bought a Pro-Ject Phono Box E Phonograph Preamplifier from Amazon and then a new stylus - an Ortofon Stylus 10.

I had a voucher for my recent 40th so I decided to dive right in. I'll report back once I have it all set up. I chose the Pro-Ject Phono Box E Phonograph Preamplifier based on a video I saw on youtube - https://www.youtube.com/watch?v=tiQ95w_PNZ8
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Old 11th Apr 2020, 6:21 pm   #9
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Default Re: DUAL CS505-2 too quiet

Hey guys - just to report back. My apologies for the huge delay. Things have been very distracting with Covid. I hope everyone is well.

So an update. I ordered a new stylus for the Dual - an Ortofon Stylus 10. I bought that for £50 on amazon.co.uk. I also ordered a Pro-Ject Phono Box E Phonograph Preamplifier from amazon.co.uk for £60.

When I connected the pre-amp and ran it into the Sony LBT-V701 I was getting a huge amount of HUM. I'm not exactly sure what is causing that as I have grounded the Dual. But weirdly it seems to be very intermittent. I'll no doubt work out what's causing it before long - but right now, it's not occurring.

So the good news is I got the Dual back up and running! I learned loads in doing it and apart from a few frustrations, I had a lot of fun. I feel it was a very worthwhile project as I know feel I've earned a few stripes and broadened my knowledge a bit.

Thanks to paulsherwin, PJL, Edward Huggins and mickm3for for offering your thoughts. All that's left to do now is to enjoy my records again. And with this lock down, it's perfect timing for that!

Stay well everyone - and thanks again!
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Old 11th Apr 2020, 6:58 pm   #10
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Default Re: DUAL CS505-2 too quiet

How did you ground the Dual?

You need to ground it at the pre-amp but often there is no grounding post.

One way you could do it, is to undo the one of the screws scrape away some of the paint and connect the ground wire to that.

Another method is to open up the turntable, find the box where the audio and ground cables go into, open it up, and connect a small link between the ground wire terminal and ONE of the audio cables' screen.
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Old 11th Apr 2020, 7:39 pm   #11
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Default Re: DUAL CS505-2 too quiet

Hi Michael.

I grounded the Dual by attaching the ground to a post at the back of the pre-amp.

But maybe there is some other issue at play.

The HUM I mentioned is significant. But it is intermittent and seems to have vanished. I have a feeling though that were I to move the cabling too much it might return.

And there is a persistent circling woosh sound - very low level now. I hear it in between tracks that I'm playing.

I'm using a very recent pressing of the White Album so I'm confident it's the equipment, not the vinyl. I can live with the woosh for today!
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Old 11th Apr 2020, 9:47 pm   #12
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Default Re: DUAL CS505-2 too quiet

I see that you have bought a new Ortofon Stylus. Is it a genuine Ortofon? This may have not been neccessary as it will have no affect on the volume level. To make sure that you have fitted this properly, check its geometry - vertical when viewed from the front and a -15 degree negative rake when viewed from the side. Also I suggest you re-insert the old stylus and see how it plays on that and if that "whoosh" sound you can hear now goes away. Please advise.
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Old 11th Apr 2020, 11:10 pm   #13
Michael Maurice
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Default Re: DUAL CS505-2 too quiet

Does the hum come from both speakers?

Does it come and go when the cables and specially the plugs are moved?

I have had problems with these cables and it might be better in the long run to fit a new cable and plugs.

From what I can gather modern vinyl pressings are not that good so try an old pressing before blaming the Dual.
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Old 12th Apr 2020, 12:53 pm   #14
khanrahan
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Default Re: DUAL CS505-2 too quiet

HI Michael -

Yes the hum comes from both of the speakers. I might try and record it later and pop it on youtube so you can see what I'm talking about.

Yes it does come and go when the cables are moved - at least it did yesterday. I'm going to test everything out again today.

Regarding the circling woosh sound - maybe it is due to the recent pressing - I'll try an older pressing today too.

The other thing that might contribute is - I did fit a new needle and although I think it's aligned correctly I cant be 100% sure.

I'll recheck everything today and report back. Thanks again for your thoughts! I appreciate them.
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Old 12th Apr 2020, 4:53 pm   #15
khanrahan
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Default Re: DUAL CS505-2 too quiet

Hi Michael,

I seem to be set up okay now. The loud hum that I was getting yesterday - is gone (Unless I start unplugging the L or R audio from the Preamplifier - then it comes back for a moment). Once everything is seated however, all is okay. So I'm going to leave that well enough alone. It's a little temperamental but not a concern right now. Frankly I think I just need to look at upgrading the other components of my system now.

The circling woosh sound I was experiencing seems to be gone too. I think it may have been down to the arm not being balanced properly. There was also some drift happening when I lowered the arm - which I realised was partly down to the table not being on a totally flat surface. That's now sorted. Alternatively it's possible that it was due to the pressing I was testing with. I'm using a different album now and all is well.

So the hum - sorted. The circling woosh - sorted.

I'm pretty happy with that. I've uploaded a video to let you see it in action if you're bored/curious! Hopefully youtube does not delete it for including Neil Young . . .

https://youtu.be/DoiXEajQA3E
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