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Help with Solo SgrII

Printed From: Graham Slee Hifi System Components
Category: Headphone Audio
Forum Name: Graham Slee Headphone Amps
Forum Description: Questions, answers and product information zone for Graham Slee Headphone Amplifiers
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=5546
Printed Date: 06 Feb 2023 at 7:09am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: Help with Solo SgrII
Posted By: VenetianGambler
Subject: Help with Solo SgrII
Date Posted: 06 Nov 2022 at 2:59pm
Hi. Just got a solo SGRII and hooked it up to the tape loop of my Naim 62 preamp. Headphones are Grado sr80. 

I don’t have the greatest hearing but I have to have the amp turned up full in order to get anything like listenable (to me) and even then I wish I had 10% more at least. 

This is with either CD or vinyl as the source going through the Naim. Does this sound right? I’ve tried either input. Next is to try and find an entirely different source but I’ll have to hope I’ve got the cabling. 



Replies:
Posted By: Chris Firth
Date Posted: 06 Nov 2022 at 3:10pm
The Grados are high sensitivity, so it shouldn't take a lot to drive them.
Can you post pictures to show how things are connected up?


Posted By: VenetianGambler
Date Posted: 06 Nov 2022 at 5:06pm
Ok so something isn’t right then. I’m not home anymore but I’ve literally got a din to 4 x rca cable out the back of my Naim pre amp - obviously 1 pair is in and the other out - but only one pair provides any audible audio into the solo. 

I’ve ordered a 3.5mm to rca cable to try amplifying the signal out of a iPad or something - to see if the amp is at fault. 


Posted By: Fatmangolf
Date Posted: 06 Nov 2022 at 6:04pm
Some amps short inactive inputs to cut crosstalk on the selected input  Does it change headphone if the Naim amp is using that source/input?

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Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Chris Firth
Date Posted: 06 Nov 2022 at 7:24pm
Looking at manualslib, and it says something about the tape output into 600 ohms is 75mV.
That looks to be quite low.


Posted By: Fatmangolf
Date Posted: 06 Nov 2022 at 7:51pm
I think you are onto something there Chris.

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Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Chris Firth
Date Posted: 06 Nov 2022 at 7:55pm
My amplifier kicks out volts, not millivolts from the tape out.


Posted By: VenetianGambler
Date Posted: 06 Nov 2022 at 8:34pm
Originally posted by Chris Firth Chris Firth wrote:

Looking at manualslib, and it says something about the tape output into 600 ohms is 75mV.
That looks to be quite low.

So what does this mean? Guessing you’re saying there’s likely nothing wrong with either how I’ve got it connected, but also no fault with the amp - and the volume I’ve got is all I can expect? 


Posted By: Chris Firth
Date Posted: 06 Nov 2022 at 9:09pm
Originally posted by VenetianGambler VenetianGambler wrote:

Originally posted by Chris Firth Chris Firth wrote:

Looking at manualslib, and it says something about the tape output into 600 ohms is 75mV.
That looks to be quite low.

So what does this mean? Guessing you’re saying there’s likely nothing wrong with either how I’ve got it connected, but also no fault with the amp - and the volume I’ve got is all I can expect? 
Possibly.
Give John C a call - +44 (0) 1909 568739 and +44 (0) 7947 107188 during normal office hours.
See if he can look into the problem for you.


Posted By: VenetianGambler
Date Posted: 06 Nov 2022 at 9:12pm
Originally posted by Chris Firth Chris Firth wrote:

Possibly.

Ok thanks. I guess I’ll be returning it. 


Posted By: Fatmangolf
Date Posted: 06 Nov 2022 at 9:23pm
To be fair the problem seems to be the low level of the Naim tape output. Have you tried connecting a source like cd player direct to the Solo?

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Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: VenetianGambler
Date Posted: 06 Nov 2022 at 9:32pm
Originally posted by Fatmangolf Fatmangolf wrote:

To be fair the problem seems to be the low level of the Naim tape output. Have you tried connecting a source like cd player direct to the Solo?

Not yet - but that wouldn’t be amazingly practical long term as I have a cd and turntable 


Posted By: BackinBlack
Date Posted: 07 Nov 2022 at 11:08am
The NAC 62 appears to have 2 line level outputs one 4 pin and one 5 pin, could you use one of these to feed the Solo?


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Just listen, if it sounds good to you, enjoy it.


Posted By: VenetianGambler
Date Posted: 07 Nov 2022 at 11:13am
Originally posted by BackinBlack BackinBlack wrote:

The NAC 62 appears to have 2 line level outputs one 4 pin and one 5 pin, could you use one of these to feed the Solo?

Hiya - not sure where you're seeing this. I think there's only the one to the power amp (which is obviously in use), and the tape loop. Is that what you mean? 


Posted By: BackinBlack
Date Posted: 07 Nov 2022 at 12:36pm
On further reading of the manual, am I right in thinking that if you're using a Hi-Cap power supply then one of the outputs will be used as the power input from the Hi-Cap. If so only one output will be available unless you have a special lead made.

Ian


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Just listen, if it sounds good to you, enjoy it.


Posted By: VenetianGambler
Date Posted: 07 Nov 2022 at 12:44pm
Originally posted by BackinBlack BackinBlack wrote:

On further reading of the manual, am I right in thinking that if you're using a Hi-Cap power supply then one of the outputs will be used as the power input from the Hi-Cap. If so only one output will be available unless you have a special lead made.

Ian

Yes it's something like that. It's all quite complicated I think.


Posted By: VenetianGambler
Date Posted: 07 Nov 2022 at 12:48pm
I am wondering if I'm getting somewhere though.

The difference in output between my turntable and CD player is considerable, so much so that I have attenuated plugs on my CD player so that I don't get a nasty shock when I switch inputs on my amp.

I've removed these plugs to see what the Solo would do. My hearing isn't amazing, and I favour loud listening (!) - but with the plugs removed, 12 o'clock on the Solo is now acceptable. Would this be what you would expect?

So now this means that it's potentially not the Solo, OR the naim amp that's the issue - but in fact the gain / output perhaps of the RIAA Phono boards I have in the Naim amp are the problem.




Posted By: Graham Slee
Date Posted: 07 Nov 2022 at 1:22pm
Firstly:

The tape output can be found from here: https://www.avoptions.com/downloads/manuals/Naim-Audio-Owners-Manual-1989.pdf - https://www.avoptions.com/downloads/manuals/Naim-Audio-Owners-Manual-1989.pdf

75mV

The Solo SRGII sensitivity is

Input sensitivity (for specified power output) - 32 Ohms: 250mV rms; 600 Ohms: 775mV rms

For the Grado's it is 10dB low, and -10dB relates to approx. 1/10th power and 1/10th power sounds half as loud.

I could see that the output playing vinyl might be low, but not the CD, until I read that you have attenuated plugs, so that now makes sense.

Now, all things being equal, the Solo up full should sound twice as loud as at 12-noon, because the difference is 10.

So we're now on the same page.

Also note that the Solo's are made so that the volume control can be used at any position to assist in matching a number of sensitivities, unlike most integrated's and preamps where anything much higher than 1pm distorts badly.

So, by removing the attenuators you now have a healthy signal, and you can turn the Solo up as high as you want (but eventually it may clip, but by then it should be too loud anyway).

The remaining problem being insufficient gain from vinyl, and I'm afraid that's how it was in the 70s and 80s when your NAC was designed.

The DIN standard was adapted into IEC 1938 (now IEC 61938), which was first published in 1996 (that's what my copy tells me), and domestic line level, which such things are, is 245mV, and definitely not 75mV.


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Not simple enough for Google-Bot to understand...


Posted By: VenetianGambler
Date Posted: 07 Nov 2022 at 1:36pm
Originally posted by Graham Slee Graham Slee wrote:

Firstly:

The tape output can be found from here: https://www.avoptions.com/downloads/manuals/Naim-Audio-Owners-Manual-1989.pdf - https://www.avoptions.com/downloads/manuals/Naim-Audio-Owners-Manual-1989.pdf

75mV

The Solo SRGII sensitivity is

Input sensitivity (for specified power output) - 32 Ohms: 250mV rms; 600 Ohms: 775mV rms

For the Grado's it is 10dB low, and -10dB relates to approx. 1/10th power and 1/10th power sounds half as loud.

I could see that the output playing vinyl might be low, but not the CD, until I read that you have attenuated plugs, so that now makes sense.

Now, all things being equal, the Solo up full should sound twice as loud as at 12-noon, because the difference is 10.

So we're now on the same page.

Also note that the Solo's are made so that the volume control can be used at any position to assist in matching a number of sensitivities, unlike most integrated's and preamps where anything much higher than 1pm distorts badly.

So, by removing the attenuators you now have a healthy signal, and you can turn the Solo up as high as you want (but eventually it may clip, but by then it should be too loud anyway).

The remaining problem being insufficient gain from vinyl, and I'm afraid that's how it was in the 70s and 80s when your NAC was designed.

The DIN standard was adapted into IEC 1938 (now IEC 61938), which was first published in 1996 (that's what my copy tells me), and domestic line level, which such things are, is 245mV, and definitely not 75mV.

Brilliant Graham - thank you. 

Does this mean that this would likely be resolved with a different phono pre-amp?

At the moment, I've got Naim phono boards in the NAC which are presumably of a similar vintage - and like you said, have 70s-80s style gain.

Would getting one of your own phono amps, and running it into a different source input on the NAC create a bit more equilibrium between the CD and vinyl? 


Posted By: Graham Slee
Date Posted: 07 Nov 2022 at 1:57pm
Originally posted by VenetianGambler VenetianGambler wrote:

Would getting one of your own phono amps, and running it into a different source input on the NAC create a bit more equilibrium between the CD and vinyl? 

Erm yes, but I didn't want to sound like a salesman taking advantage of your situation.

As you're nearby, the guy you were talking to this morning (John) can assist you, and will let you borrow any of the stages we do, and then before risking any money changing hands, you can satisfy yourself by using it with the NAC. It shouldn't cause any problems as the voltage rail in the NAC should be high enough so as not to clip with either the CD player without attenuators, or phono stage, but it's best to try it first.

Then, if it does work, this topic acts as a record to assist others who may have a similar problem. Wink




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Not simple enough for Google-Bot to understand...


Posted By: VenetianGambler
Date Posted: 07 Nov 2022 at 2:00pm
Originally posted by Graham Slee Graham Slee wrote:

Originally posted by VenetianGambler VenetianGambler wrote:

Would getting one of your own phono amps, and running it into a different source input on the NAC create a bit more equilibrium between the CD and vinyl? 

Erm yes, but I didn't want to sound like a salesman taking advantage of your situation.

As you're nearby, the guy you were talking to this morning (John) can assist you, and will let you borrow any of the stages we do, and then before risking any money changing hands, you can satisfy yourself by using it with the NAC. It shouldn't cause any problems as the voltage rail in the NAC should be high enough so as not to clip with either the CD player without attenuators, or phono stage, but it's best to try it first.

Then, if it does work, this topic acts as a record to assist others who may have a similar problem. Wink



Again, that's brilliant Graham - and no sense of you taking advantage from here. 

I will be in touch with John.


Posted By: BackinBlack
Date Posted: 07 Nov 2022 at 3:18pm
Glad to see some progress towards an answer.


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Just listen, if it sounds good to you, enjoy it.



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