Low Volume from Dual Turntable (via preamp) with Cambridge Audio Amp

[Valentiaman]

I have a Dual 505 turntable (which I bought in 1985), connected to a Cambridge Audio Azur 540A amp (which I bought about 8 years ago).

The amp does not have a phono stage, so I have used both a Nad and Berhinger preamp with the Dual, plugged into the DAB inputs on the Azur (I have also tried every other input on the amp).

The volume from the turnable is low and muddy by comparison to the Sony CD player. I need to take the volume up to at least halfway, and usually 2/3rd up on the Azur to hear records. At that point, there is a noticeable hum from the speakers (I presume it's the amp).

I have had conflicting advice, from audiophile friends as to the cause. Some say the amp is the problem, and a hifi dealer told me it was the turntable (this was after I mentioned possibly buying the Rega Planar 1).

I would like to get this sorted, as I'm getting back into listening to vinyl. My speakers are Monitor Audio Bronze 2.

Any help would be welcome.

Stephen

[Smegger68]

What cartridge is fitted to the Dual?

[walpurgis]

What cartridge is in the Dual?

[Valentiaman]

Thanks guys, the cartridge is an Audio Technica 95e.

[walpurgis]

That should drive an MM input OK and any of the line level inputs on the amp should work with the phono stage. Is the stylus good? A worn stylus can reduce output.

[Valentiaman]

It's a brand new stylus and cartridge, less than a week old. I changed them both just in case that was the issue, but it sounds the same, low volume and muddy. My Sony CD player is very loud through the same amp.

(BTW Geoff, I seem to have duplicated this thread, below, and can't see how to delete it).

[walpurgis]

(BTW Geoff, I seem to have duplicated this thread, below, and can't see how to delete it).

Removed.

[walpurgis]

Double check the headshell connections to the cartridge. It could be a partial short or poor contact.

[Valentiaman]

They do seem quite loose, but not sure how to rectify it.

[walpurgis]

Gently crimp the tags a bit with narrow nosed pliers.

Are you sure the tags are on the correct pins? It occurs to me that an out of phase cartridge could be a potential cause of the symptoms.

[struth]

The 95 only outputs 3.5mv so not the loudest cart around but saying that it shouldnt be low and muddy.. tracks at 2gm aprox and loaded on mm at 47kohm. Make sure if the pre has a mc setting or loading options that you have it on mm and 47k. Also check you have the cart leads on correctly.

[struth]

Got a feeling its not marked on cart so you will need an online diagram to show what colour goes where. Its not same as other carts, if memory serves.

[Valentiaman]

Gently crimp the tags a bit with narrow nosed pliers.

Are you sure the tags are on the correct pins? It occurs to me that an out of phase cartridge could be a potential cause of the symptoms.

I've checked the tags with the pins using the chart that came with the cartridge and also the manual for the dual that I got online. I think I've got them right, although the cartridge only has a + sign and L and R (not a - sign). I'll give them another go and crimp them and come back.

Thanks again for all the help.

[Valentiaman]

The 95 only outputs 3.5mv so not the loudest cart around but saying that it shouldnt be low and muddy.. tracks at 2gm aprox and loaded on mm at 47kohm. Make sure if the pre has a mc setting or loading options that you have it on mm and 47k. Also check you have the cart leads on correctly.

I've tried 2 preamps. The Nad is definitely on MM and the Berhingher is only MM. Tracking is at 2gm. Not sure about 47kohm, as I can't see anywhere to set that on the preamps, and I assume they are at the right levels.

[struth]

https://www.petervis.com/record_players_and_turntables/audio-technica-cartridge-wiring/wiring/audio-technica-cartridge-pinout.gif

should be this way

[Valentiaman]

https://www.petervis.com/record_players_and_turntables/audio-technica-cartridge-wiring/wiring/audio-technica-cartridge-pinout.gif

should be this way

I was half-hoping I'd got them the wrong way around, but no, that's how I have them. Just re-connected them and crimped harder, but to no avail. It's listenable at about 2 O'Clock on the amp volume cranker, 6 O'clock being full blast, which would break windows with the CD player. But, the hum from the amp is noticeable after 1 O'clock and I can't help feeling something is amiss.

[struth]

unlikely but possible both pres are faulty. amp working with cd ok suggests its ok. faulty cart setup, faulty cart, something wrong with the tonearm wiring maybe.

[Valentiaman]

unlikely but possible both pres are faulty. amp working with cd ok suggests its ok. faulty cart setup, faulty cart, something wrong with the tonearm wiring maybe.

So, you're against the "it's the amp" theory? And, should I be getting that hum from the amp at high volumes?

[Valentiaman]

Hold the front page! I may have exaggerated the volume from the amp, with the CD player. It now seems pretty quiet at about 1/4 volume (9 O'clock) and needs to go to 11 'Clock to be listening in my large room, and then to 1 O'Clock to be loud, so only about 2 or 3 "notches" behind the turntable, if I'm honest. The hum comes in at about 1 O'clock.

[walpurgis]

Hum could be an earthing issue.

[struth]

could be amp then... worth trying another if you can borrow one..

[Valentiaman]

Thanks again Grant, it's unlikely I can find one on my Island(!) but I've got my eye on a new Marantz PM5005, good deal on Amazon right now - €55 less than I could get it from a Dublin dealer, even with postage costs. Is that a good match for the Dual 505 (assuming it's OK).

[struth]

dont know much re the dual 505 tbh. more of a point will be the phono stage. decent one with a decent gain structure might be a need too, although the at95 is a bottom end cart it can sound pretty decent with a good phono stage. also what are your speakers

[Barry]

The hum could be caused by having the cartridge return leads (the blue and green coloured leads) swapped around. They may be correctly connected on the cartridge pins but could be incorrect within the headshell. It happened to me once.

[Valentiaman]

dont know much re the dual 505 tbh. more of a point will be the phono stage. decent one with a decent gain structure might be a need too, although the at95 is a bottom end cart it can sound pretty decent with a good phono stage. also what are your speakers

Speakers are Monitor Audio Bronze B2. Preamps are Behringer PP400 (47Kw) and NAD PP2 (47 kohms + 200 pf).

[Valentiaman]

The hum could be caused by having the cartridge return leads (the blue and green coloured leads) swapped around. They may be correctly connected on the cartridge pins but could be incorrect within the headshell. It happened to me once.

Thanks Barry. The hum is there even with the CD connected, or with nothing other than the speakers connected, and at about slightly more than halfway up on the volume dial.

[Barry]

Thanks Barry. The hum is there even with the CD connected, or with nothing other than the speakers connected, and at about slightly more than halfway up on the volume dial.

Then it sound like the problem is with the amplifier. If you only have a CD player connected but not playing, is the hum there with the volume set half way?

[Macca]

Perfectly normal to have to wind the volume up quite a bit more with vinyl. Phono stages don't tend to have as high an output voltage as a CD player. The hum sounds like it could be a ground loop. Alongside the phono cables running out of the TT you should have an earth lead. That needs to be connected to the phono stage. If it is already connected try disconnecting it.

[twotone]

Thanks Barry. The hum is there even with the CD connected, or with nothing other than the speakers connected, and at about slightly more than halfway up on the volume dial.

Sounds like an earth issue, try moving the phono stages away from the amp or TT or TV etc.

I had a similar problem with my current cartridge and previous amp, records were quiet at the same volume setting as the other line stages (tuner, CD etc) so I had to crank the amp's volume up to about almost full when listening to records but obviously had to remember to turn the volume down if I listened to another source I then changed the amp and bought an on-board MM module for the amp and now the same cartridge plays at the same volume level as all of the other line stages.

[Macca]

Thanks Barry. The hum is there even with the CD connected, or with nothing other than the speakers connected, and at about slightly more than halfway up on the volume dial.

That sounds like the amp. If the hum is always the same level regardless of the volume it is the transformer. If that's the case you'll need a new amplifier, repairing it won't be cost effective unless you can do it yourself.

[walpurgis]

Thanks again Grant, it's unlikely I can find one on my Island(!) but I've got my eye on a new Marantz PM5005, good deal on Amazon right now - €55 less than I could get it from a Dublin dealer, even with postage costs. Is that a good match for the Dual 505 (assuming it's OK).

I reckon you'll probably be OK with the Marantz. It's not an amp I know, but it seems well liked and does not cost a fortune. Your phono stages should work with it.

[walpurgis]

That sounds like the amp. If the hum is always the same level regardless of the volume it is the transformer. If that's the case you'll need a new amplifier, repairing it won't be cost effective unless you can do it yourself.

Martin is right. If the hum is there regardless of what source is feeding inputs, I'd guess it's knackered!

[Valentiaman]

Thanks for the recent replies, I'll try and respond to each Below:

Originally Posted by Macca: That sounds like the amp. If the hum is always the same level regardless of the volume it is the transformer. If that's the case you'll need a new amplifier, repairing it won't be cost effective unless you can do it yourself.

I can hear the hum from halfway up on the volume dial. It does get a bit louder as the volume goes higher, but it stays the same tone and never gets very loud.

Originally Posted by Macca: Alongside the phono cables running out of the TT you should have an earth lead. That needs to be connected to the phono stage. If it is already connected try disconnecting it.

I disconnected the ground wire and the volume was the same, but the "click" when the tonearm moved to the record was much louder through the speakers.

Originally Posted by Two Tone: Sounds like an earth issue, try moving the phono stages away from the amp or TT or TV etc.

Because of the short ground wire, I can't move the preamp very far from the amp or TT, but it's not resting on either of them.

[struth]

Phone stage may be picking up noise. Try moving it by extending the earth. Also try moving other wires behind like interconnects away from mains cables and everything away fro
Phono

[walpurgis]

It's noisy on CD too though Grant.

[Valentiaman]

It's noisy on CD too though Grant.

It's buzzing with nothing plugged in except speakers.

[Smegger68]

It's buzzing with nothing plugged in except speakers.

You may have some hum coming from another appliance or noisy mains. Try going round the house turning things like fridges and heating off and see if the hum goes. if it does, a mains filter is in your future.

[Valentiaman]

You may have some hum coming from another appliance or noisy mains. Try going round the house turning things like fridges and heating off and see if the hum goes. if it does, a mains filter is in your future.

Turned off fridge, electric cooker, immersion heater and TV / Sound bar. No change. I have only been in this house 18 months (and it's bigger than my last place) and I'm fairly sure the buzzing was happening there too. But if it is a gound loop (I think that's what it's called), I can't find it.

[Barry]

Try disconnecting all the sources from your amplifier, and then see if the hum is still there regardless of which source is chosen on the amp.

[Valentiaman]

Try disconnecting all the sources from your amplifier, and then see if the hum is still there regardless of which source is chosen on the amp.

Already done that Barry...mentioned it a few times in previous posts. It is.

[walpurgis]

If the amp mains lead wall plug is not a mouded on type open it and check that the earth is not loose.

[Barry]

Already done that Barry...mentioned it a few times in previous posts. It is.

Ah OK - I though you had tried the amp without any source switched on but still connected, and wanted to eliminate the small possibility that the interconnects themselves may be picking up hum and RFI.

[Valentiaman]

If the amp mains lead wall plug is not a mouded on type open it and check that the earth is not loose.

Thanks again. Unfortunately, all wires were securely fastened in the plug!

[Edward]

It's buzzing with nothing plugged in except speakers.


If easy to do, try temporarily moving the amp and speakers alone to another part of your house (i.e. a different part of the ring main) to see if the hum is still present. And ensure nothing else other than the amp is plugged into that section of the mains circuit.

Do you have any other speakers you can try? (sorry you may have already said). Even though it should not cause hum double check speakers are wired to the amp in phase. Is the buzzing coming from both speakers? If not switch them around.