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Rothwell input attenuators, well worth using! (MF A1000)

C

cpg

pfm Member
I am currently using my "winter" amplifier, a Musical Fidelity A1000 that works predominantly in Class A, to enjoy music and heat the room up at the same time.
Initially I just fed the output of my Beresford DAC straight into the CD input of the amp and thought the sound was good but rather "hard" in the treble area. I then compared the CD player analogue output to the Beresford DAC output and was surprised to hardly hear any difference between the two of them! Both sounded hard in the treble.
I thought this was strange as I previously thought the Beresford DAC was much better in my "summer" set up.
After about a week it suddenly struck me that perhaps the MF CD input was more sensitive than my other amp and slightly overloading.
I fished out a pair a Rothwell input attenuators that I bought about 20 years ago and installed them before the CD input of the MF amp. Problem solved! The harshness disappeared and everything sounds much better.

This raises the question how many older amplifiers are not designed to deal with a 2V, perhaps higher?, output from a CD player or DAC.

Has anyone else had a similar experience?
 
It is definitely not overloading and if it's like most amps these days cannot be overloaded as the vol control is likely at the input.
Anything designed after around 1983 will be designed for 2V CD input levels...
 
Arkless Electronics said:
It is definitely not overloading and if it's like most amps these days cannot be overloaded as the vol control is likely at the input.
Anything designed after around 1983 will be designed for 2V CD input levels...
Click to expand...
What would you attribute it to? I’ve heard exactly the same on a new amp (Sugden ANV 50) and Rothwell attenuators sorted that, too. My Albarry pre (~2015 vintage) had a CD input that is attenuated by about 15dB compared to the other line level inputs, and sounded more natural and less hard than using CD through the other line inputs. CD player in all cases is a dCS whose output is textbook Red Book 2V.
 
Sue Pertwee-Tyr said:
What would you attribute it to? I’ve heard exactly the same on a new amp (Sugden ANV 50) and Rothwell attenuators sorted that, too. My Albarry pre (~2015 vintage) had a CD input that is attenuated by about 15dB compared to the other line level inputs, and sounded more natural and less hard than using CD through the other line inputs. CD player in all cases is a dCS whose output is textbook Red Book 2V.
Click to expand...

I wouldn't attribute it to anything specific but it certainly has nothing to do with input overload. If an amp has specific input with attenuation for CD then this should be used as it may be one of the amps that doesn't have vol control at input and can be overloaded... These are in the minority nowadays but still plenty around.
 
I guess it may just be that the particular volume pot in question sounds better a bit wider open? 15db is a fair twist on most.
 
Yes, excellent devices, I've used a little attenuation on CD players for years sometimes via Rothwell or Goldenjacks plugs as I've always found the output of CD players much higher than built in phonostages or indeed outboard phonostages, ideally I'd like the same volume whenever switching from one source to another, I'm currently using an attenuated cable (-6 db) between CD player and pre-amp.
 
Many, many, many years ago I had a Musical Fidelity A1001 and also used Rothwell Attenuators on the CD input, they must have worked. I might fish them out and have a play.
 
Darren L said:
I'm currently using an attenuated cable (-6 db) between CD player and pre-amp.
Click to expand...

Same here. My Lector CDPs have both had high output (3.4 V ish) and most CDs played at 'needle knock' on the pre's meters. Tried -10 and -15dB attenuators, but they definitely affected s.q. Then bought Goldenjacks -6 dB, which are perfect and, a.f.a.I.can tell, have no s.q. degradation.

I got the strong impression from this AND reading many threads on attenuation in the past (pro and anti), that the more the attenuation, the greater the sonic impairment. Just an observational theory which I'm sure will be shot down in flames !:)

CPG ...All line inputs on an amp should be the same, surely, and if the input signal was higher than desired, you'd notice on vol. control position. However, as Jez says, there may be exceptions.
 
Yup use them on the CD input of a Vincent SV-237MK into Audionote ANK/LX- surprised to find got better sound quality, much easier to listen and could use more control of the volume knob.:)

Should add these were the Goldenjacks -10db items.
 
Mike Reed said:
Same here. My Lector CDPs have both had high output (3.4 V ish) and most CDs played at 'needle knock' on the pre's meters. Tried -10 and -15dB attenuators, but they definitely affected s.q. Then bought Goldenjacks -6 dB, which are perfect and, a.f.a.I.can tell, have no s.q. degradation.

I got the strong impression from this AND reading many threads on attenuation in the past (pro and anti), that the more the attenuation, the greater the sonic impairment. Just an observational theory which I'm sure will be shot down in flames !:)

CPG ...All line inputs on an amp should be the same, surely, and if the input signal was higher than desired, you'd notice on vol. control position. However, as Jez says, there may be exceptions.
Click to expand...

Yep that must be given both barrels!! Attenuators do not degrade sound quality in any way. That is fact.
They are also identical to every normal vol control and to the gain setting network in every amplifier.
 
cpg said:
This raises the question how many older amplifiers are not designed to deal with a 2V, perhaps higher?, output from a CD player or DAC.
Click to expand...

I don't know but it's an issue for sure. I have some attenuators and they can indeed be useful.
 
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