Seeking knowledge
Printed From: Graham Slee Hifi System Components
Category: And the rest
Forum Name: Amplification
Forum Description: Share your interests or views on amplifiers, preamps, etc
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=2431
Printed Date: 18 Apr 2024 at 1:15pm
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: Seeking knowledge
Posted By: ICL1P
Subject: Seeking knowledge
Date Posted: 21 Jan 2015 at 12:51pm
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i currently have an integrated amplifier from a mainstream manufacturer. In the long term I expect I'll replace it with a Majestic and a pair of Proprii. As some of you will know the amp has been doing its stuff running in a pair of Frugal Horn Mk3s and mostly low volume. Over the last few days when I turn the volume right down on the amp I can still hear it playing in the room next door. What's occurring? ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Replies:
Posted By: Graham Slee
Date Posted: 21 Jan 2015 at 2:02pm
It's OK Ifor, Mulder and Scully are already on the case... they're inside your Frugal Horns...   ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
ICL1P wrote:Posted By: Ash
Date Posted: 21 Jan 2015 at 2:24pm
Well each speaker cabinet is large (and heavy) so when directly coupled with the hard floor and indirectly coupled with the walls of the listening environment (all have a low frequency of resonance), the vibrations are synergistic (they summate) and depending on the damping properties of the materials, the vibrations would probably be audibly transmitted several metres even if the source is at low amplitude. Amplitude increases substantially close to or at resonance. Is there any way you can decouple the speaker cabinets from the room further???
 ------------- We do not see things as they are. We see things as we are. |
Posted By: ICL1P
Date Posted: 21 Jan 2015 at 2:28pm
Ash, what I thought I said was that the amplifier volume control no longer silences the amplifier when turned all the way down. ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: BackinBlack
Date Posted: 21 Jan 2015 at 2:32pm
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Perhaps it really goes from 1 to 11, not 0 to 10? ------------- Just listen, if it sounds good to you, enjoy it. |
Posted By: Ash
Date Posted: 21 Jan 2015 at 2:32pm
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That's interesting. What is the source of the signal going into the amplifier? So there's no other gain controls then? ------------- We do not see things as they are. We see things as we are. |
Posted By: ICL1P
Date Posted: 21 Jan 2015 at 2:39pm
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I've tried different sources. TT through Reflex, TV and Pi through a DAC. ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: Dave Friday
Date Posted: 21 Jan 2015 at 2:51pm
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My guess is that the chassis end of the volume control has a dry joint,how are you with a test meter? ------------- lp12,oc9mk3,ca610p,krimson40watt pa,kef105.4 |
Posted By: Ash
Date Posted: 21 Jan 2015 at 2:51pm
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A limitation of the potentiometer travel, I guess. Another example of not being fully off is with the Bitzie. When its Alps volume pot is turned fully anticlockwise, there is still very very low level audio heard in the left channel of headphones (right channel was silent for me). It's not a blue velvet, which is the reason for the slight inbalance. Quite minor though. Although your issue isn't with one channel; it's both. All depends on how well matched it is for the input sizes it typically receives. At least with the TV input (analogue, I assume?), you can use the TV's own volume to solve the problem??
With a second volume control on the audio chain (I had Solo ULDE or Proprius for this), the resistance could then be altered such that no signal could be heard in either channel.
------------- We do not see things as they are. We see things as we are. |
Posted By: BAK
Date Posted: 21 Jan 2015 at 2:52pm
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Ifor, (1) Have you been able to turn the volume all the way down to "0" before and have the actual sound go silent? If so and it does not now, the volume control may be dirty from lack of use at the "bottom" of travel. The volume control, if dirty, can be cleaned with control cleaner; sometimes a dirty control can be rotated back and forth (or up and down) many times to clear the debris. (2) Do you have another sound system in the other room? a TV, radio, or other with the the same program material... Here to help, ------------- Bruce AT-14SA, Pickering XV-15, Hana EL, Technics SL-1600MK2, Lautus, Majestic DAC, Technics SH-8055 spectrum analyzer, Eminence Beta8A custom cabs; Proprius & Reflex M or C, Enjoy Life your way! |
Posted By: BackinBlack
Date Posted: 21 Jan 2015 at 3:10pm
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The Frugels are quite sensitive, so whilst less sensitive speakers perhaps don't receive enough drive for audible sound the Frugels will produce a more audible output. It is not uncommon for the zero of volume controls not to be a true zero as there may be either a mechanical end error or there may be not be absolutely zero resistance at the end of the potentiometer track, caused by dirt on the wiper. Sometimes a few vigourous end to end rotations of the control might clean it, otherwise don't worry unless the balance is significantly out. ------------- Just listen, if it sounds good to you, enjoy it. |
Posted By: ICL1P
Date Posted: 21 Jan 2015 at 3:33pm
What's a test meter?  ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: ICL1P
Date Posted: 21 Jan 2015 at 3:38pm
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This just in from the manufacturer: "Hello Ifor Phillips, Thank you for your email. It sounds like the volume control may be faulty on your Amplifier wot we made. The cost of replacing the volume control and service is: VOLUME CONTROL £ 24.40 plus VAT £ 4.88 TOTAL £29.28 LABOUR £ 162.00 for 1.5 hrs carriage £ 26.40 UK only The turnaround is usually 3-5 days" I think I'll try some of the suggestions of forum members rather than fork out £162 for their labour. Thanks everyone. ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: Ash
Date Posted: 21 Jan 2015 at 3:46pm
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A digital multimeter is what I think Dave is talking about. I got a good one from B&Q a few years back for about £20. Measures eletrical resistance, capacitance, potential difference/voltage, current flow, tests electrical continuity with a beep etc. Just plug the supplied rods/probes into the device and you can test various properties of PCBs or electronic components.
That amplifier is no longer under warranty I suppose then? I just feel that if that was a GSP product, you'd get better customer service than that... I think it might be wise to investigate Dave's suggestion. If the metallic housing of the volume potentiometer is not properly "tied down", it might be left "floating" perhaps (?)
------------- We do not see things as they are. We see things as we are. |
Posted By: Chris Firth
Date Posted: 21 Jan 2015 at 3:49pm
Not with Mark Audio drivers fitted! The drive units are Alpair7 by the look of 'em |
Posted By: Graham Slee
Date Posted: 21 Jan 2015 at 4:18pm
Alps don't name their pots "Blue Velvet". I believe you are referring to an Alps RK27. The Bitzie uses an Alps RK09. The plastic on the RK27 is blue and on the RK09 green. Neither use velvet. Both (like most pots) have carbon elements deposited on SRBP by silk-screen process, and some end-resistance tolerance is allowed because of registration error. The larger the print, the smaller the percentage of error. The tolerances are given by Alps in their data sheets. As most parts are riveted or pressed together there will be errors within tolerance here too. Wipers (which output the set volume or level) are formed from thin metal sheet having spring properties such as phosphor or beryllium bronze. Each wiper is often divided into a number of wiper fingers to reduce the possibility of the track lifting - or bouncing - when operated quickly. The AC27 wipers are divided into 5, and smaller diameter pots have wipers divided into 3 or 2 wiper fingers. Over extended use, parts can wear out and the wipers can loose their springiness. DC offsets are not all that well tolerated on the RK27 (see data sheet). The elements may become loose and go slightly out of position, and this might be the cause of Ifor's problem. If the "ground" connection was lost, that channel would most likely fail to full volume. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Dave Friday
Date Posted: 21 Jan 2015 at 5:16pm
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The earthy end of the volume controls could have a low resistance " dry joint". But as you say Graham the crimping at the ends of the carbon track could be poor/ loose. I have two 10 k pots that had that problem! ------------- lp12,oc9mk3,ca610p,krimson40watt pa,kef105.4 |
Posted By: marshmid
Date Posted: 21 Jan 2015 at 5:35pm
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If the above suggestions do not solve the problem, I successfully replaced a faulty volume pot on a Cambridge P50 amplifier. Neither air or cleaning fluid improved it. The amp was worth next to nothing and the Alps pot was about £15 (maybe less) so it wasn't a difficult decision. There was a good clearance around the pot so the job was not difficult. I do not have the soldering skill to build a Genera! However, more modern amps may have limited clearance or be surface mounted? |
Posted By: ICL1P
Date Posted: 21 Jan 2015 at 6:02pm
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It's certainly not a big enough problem to send it back to the manufacturer for repair. It is several years old and I bought it second hand. Sometime soon I'll open it up and have a look. With my new found confidence and skills, I might even be tempted to replace it myself as Marsh did. Thanks everyone. ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: ICL1P
Date Posted: 21 Jan 2015 at 6:13pm
Interestingly zero volume is noticeably louder with the FH3s (Mark Audio Alpair 7.3), SPL 85.8 dB than with the Spendor A5s, SPL 86 dB.
------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: ServerBaboon
Date Posted: 22 Jan 2015 at 10:25pm
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Does the crossover in the Spenders make the difference since there is non in the frugal? ------------- Steve ------------- Various bits of GSP Kit ..well two so far, unless you count the cables that is. |
Posted By: Chris Firth
Date Posted: 22 Jan 2015 at 11:15pm
Good question! There's a whole load of bit's and pieces not manipulating the signal with the FH3/Alpair7. |
Posted By: ICL1P
Date Posted: 22 Jan 2015 at 11:41pm
Pass! ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: Fatmangolf
Date Posted: 23 Jan 2015 at 5:34pm
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That's an idea about the crossover. And I wonder if the speakers' sensitivities are slightly different at 1 watt to the manufacturers' stated figures, or not linear in their response to reduced power input compared to the 1 watt levels. Or perhaps one of the speakers has more midrange output at lower levels? ------------- 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. |