Greetings,
trying to understand i/O voltage/Impedance matching:
to explain:
1) purchased Kenwood Basic M1 Amplifier, and Basic C1 Preamp; very satisfied
M1 Amp: Input sensitivity: 1 V 47KΩ..
C1 Preamp: "Output Voltage & Impedance: 1 V/less than 600Ω, maximum output: 5V Load Impedance: 47kΩ"... everything wunderbar
2) Went shopping for additional Basic M1 (for my workshop), purchased via Ebay, UK
M1 Amp purchase also included Basic C2 Preamp (oh goody! lots of extra features!):
C2 Preamp: "Tape Rec: 150mV, 220Ω", PRE OUT: 1,000mV, 100Ω"
Assumed was included in Kenwood Basic series, was compatible...
However, at approx. 1/3 - 1/4 volume... distortion extreme (mis-match... really stupid move by Kenwood??)
To the Point:
Audient iD14 as DAC/master volume control:
(one audio source: my PC/TOSLINK)
"Maximum output level - +12dBu (0dBFS digital maximum)"
"Output Impedance <100Ω"
Audient iD14 has Balanced TRS outputs - intend to use unbalanced TS-RCA adapters
Is the iD14/M1 Basic combo a mismatch problem? (haven't tried it yet... would really hate to brick something)
solved with HiZ/Loz adapter? or DI box (before the Amp)
thank you for a useful recommendation (if this works, C2 will become a doorstop or boat anchor)
trying to understand i/O voltage/Impedance matching:
to explain:
1) purchased Kenwood Basic M1 Amplifier, and Basic C1 Preamp; very satisfied
M1 Amp: Input sensitivity: 1 V 47KΩ..
C1 Preamp: "Output Voltage & Impedance: 1 V/less than 600Ω, maximum output: 5V Load Impedance: 47kΩ"... everything wunderbar
2) Went shopping for additional Basic M1 (for my workshop), purchased via Ebay, UK
M1 Amp purchase also included Basic C2 Preamp (oh goody! lots of extra features!):
C2 Preamp: "Tape Rec: 150mV, 220Ω", PRE OUT: 1,000mV, 100Ω"
Assumed was included in Kenwood Basic series, was compatible...
However, at approx. 1/3 - 1/4 volume... distortion extreme (mis-match... really stupid move by Kenwood??)
To the Point:
Audient iD14 as DAC/master volume control:
(one audio source: my PC/TOSLINK)
"Maximum output level - +12dBu (0dBFS digital maximum)"
"Output Impedance <100Ω"
Audient iD14 has Balanced TRS outputs - intend to use unbalanced TS-RCA adapters
Is the iD14/M1 Basic combo a mismatch problem? (haven't tried it yet... would really hate to brick something)
solved with HiZ/Loz adapter? or DI box (before the Amp)
thank you for a useful recommendation (if this works, C2 will become a doorstop or boat anchor)
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Try connecting the amp to the tape output, or any others from the preamp.
1000 mV is too much input for most amps. 250 is more like it, so little wonder that you have distortion. See if the amp has different inputs, check the manual.
If needed build an impedance matching circuit, use a drop resistor to check. Multi turn preset will be handy if you do that.
Or simply connect the output from source directly to the amp input, see what happens.
1000 mV is too much input for most amps. 250 is more like it, so little wonder that you have distortion. See if the amp has different inputs, check the manual.
If needed build an impedance matching circuit, use a drop resistor to check. Multi turn preset will be handy if you do that.
Or simply connect the output from source directly to the amp input, see what happens.
matching Kenwood M1 amp and Audient iD14
The C1 preamp and M1 Power amp are matched units
The M1 Power amp has only one input... intended for C1 Output
"see what happens" smoke test is something I'm trying to avoid
I will bring my C1 Preamp down to my workshop, connect to second M1 Amp (the first combo works fine):
if distortion persists, UK seller scammed me with junk.
The C1 preamp and M1 Power amp are matched units
The M1 Power amp has only one input... intended for C1 Output
"see what happens" smoke test is something I'm trying to avoid
I will bring my C1 Preamp down to my workshop, connect to second M1 Amp (the first combo works fine):
if distortion persists, UK seller scammed me with junk.
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I thought you had a C2, as the second pre amp, which is why I suggested different inputs.
Keep us posted.
Keep us posted.
But "M1 Amp: Input sensitivity: 1 V" (and I know you know 1000mV=1V).
And there's a Volume control on the preamp Main output. Actual output level may be reduced below normal distortion level.
Both preamps are bipolar power supply. If one of the two rails has gone dead, distortion may be gross even at small output.
Ah
I did not check, it is a matched pair not intended for use separately?
The same result may be achieved by reducing the input level to the pre amp, provided it is healthy?
The first post mentions a C1 and a C2, so a little confusing.
I did not check, it is a matched pair not intended for use separately?
The same result may be achieved by reducing the input level to the pre amp, provided it is healthy?
The first post mentions a C1 and a C2, so a little confusing.
I have used my M1 basic with a dozen different preamps you should not have compatibility issues with either C series preamp if working correctly. Are you using the sigma drive (feedback-2-the-speakers) speaker cable or regular speaker wire?
The output level of the iD14, and most other pro interfaces, is approximately 2V at unbalanced output and 4V at balanced output.
This is 12-24 times the maximum acceptable input level for a 150mV input. So no, it's not stupid as Kenwood is quite clear about the levels that input can tolerate.
The Audient should be ideally connected directly to the M1. The amp sensitivity spec is confusing as it states two different input levels. If 5V is for full output, then 5V is the input sensitivity, not 1V. The schematic seems to indicate around 30dB of gain, so the input sensitivity for 127W is pretty much 1V.
The preamp can be either used as a doorstop or a boat anchor (or you could take its outputs and feed it into the iD14 analog in to add more inputs). It is really not needed in this application.
Sigma drive
Yes, sigma drive connection is the primary purpose of purchasing the M1;
thank you
Yes, sigma drive connection is the primary purpose of purchasing the M1;
thank you
Thank you...
this is the conclusion that I imagined(hoped for):
PC(TOSLINK) > Audient iD14(unbalanced T/S+RCA) > (RCA)M1
the primary function of Audient is DAC/Master volume control)
The C2 Preamp, with it's bells and whistles, could be used for other functions.
That is "Sensitivity". The maximum is not stated.
However we "know" it takes 2V because it has a clear "CD" input and most CD decks output 2V at full scale.
The input, after a remarkable lot of switching (Deoxit??) goes to a volume control. There is another vol pot further along, so there may be a corner-case that clips in the middle; but Kenwood's designers knew their stuff.
My 2 cents is on a power supply fault. Or tarnish in the maze of switches.
Impedance matching is not necessary here. Output spec give a minimum the output can drive, input spec are fine as long as they are higher than the minimum the source can drive i.e. the output spec. Typically 10 times the output spec or more is ideal for an input impedance.
The Audient outputs +12dBu at 0dBFS (0dB full signal, i.e. digital maximum level = clipping), but the M1 only needs 1V = +3dBu to reach clipping, i.e. the i14 is overdriving the M1.
You need to drop the ouput level from the i14 to match the input requirement of the M1. Note doing this will also optimise THD+N of your system! You could try the C2 to match levels, but it will likely overload with the i14's output level. If you don't want to use a preamplifier to level match you can make an inline pad, or insert a passive preamplifier. I would probably do the latter.
Make sure you only use the + and ground connection in the TRS. If you use the + and - connections from the balanced output the output signal will be 6dB more, which isn't helpful.
Use connection type 10B in the attached link to "Rane Sound System Interconnection" RANE Commercial - Knowledge Base
The Audient outputs +12dBu at 0dBFS (0dB full signal, i.e. digital maximum level = clipping), but the M1 only needs 1V = +3dBu to reach clipping, i.e. the i14 is overdriving the M1.
You need to drop the ouput level from the i14 to match the input requirement of the M1. Note doing this will also optimise THD+N of your system! You could try the C2 to match levels, but it will likely overload with the i14's output level. If you don't want to use a preamplifier to level match you can make an inline pad, or insert a passive preamplifier. I would probably do the latter.
Make sure you only use the + and ground connection in the TRS. If you use the + and - connections from the balanced output the output signal will be 6dB more, which isn't helpful.
Use connection type 10B in the attached link to "Rane Sound System Interconnection" RANE Commercial - Knowledge Base
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TRS Tip/shield > RCA Tip/Shield
thanks,
Soldered up RCA cables to TRS: TRS tip to RCA"tip'... TRS Shield to RCA "shield"... no connection to TRS "Ring":
According to LED level meter on Audient: -12dB distortion begins... approx -9Db -6dB distortion dominant.
Never even begins to approach typical volume level before distortion would be destructive (that is, compared to the original C1+ M1 setup)
Schematic suggestions for "passive preamp"? or off the shelf product that will provide the input that the M1 Amplifier expects?
Lo-Z to Hi-Z x-formers: negative audio quality impact?
The Audient iD14 (MKI) was not cheap: was looking for Burr/Brown USB DAC, with volume control.
Again, thanks for the assist, folks
John
thanks,
Soldered up RCA cables to TRS: TRS tip to RCA"tip'... TRS Shield to RCA "shield"... no connection to TRS "Ring":
According to LED level meter on Audient: -12dB distortion begins... approx -9Db -6dB distortion dominant.
Never even begins to approach typical volume level before distortion would be destructive (that is, compared to the original C1+ M1 setup)
Schematic suggestions for "passive preamp"? or off the shelf product that will provide the input that the M1 Amplifier expects?
Lo-Z to Hi-Z x-formers: negative audio quality impact?
The Audient iD14 (MKI) was not cheap: was looking for Burr/Brown USB DAC, with volume control.
Again, thanks for the assist, folks
John
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A stepped attenuator is likely to give the best level tracking between channels with no detriment to sound quality. Here's some cheap enough if you didn't want to make one yourself:
Four input, two output, 21 volume steps: SMD Dact type Stepped attenuator Passive Preamplifier | eBay
Three input, one output, 23 volume steps: Rockappella Passive Pre-Amp Stepped Attenuator Preamplifier Gold Knob 23 Point | eBay
One input, balanced/unbalanced in/out, 256 volume steps: Douk Audio 256 Step Attenuator Volume Controller RCA/ Balanced XLR Stereo Preamp | eBay
Four input, two output, 21 volume steps: SMD Dact type Stepped attenuator Passive Preamplifier | eBay
Three input, one output, 23 volume steps: Rockappella Passive Pre-Amp Stepped Attenuator Preamplifier Gold Knob 23 Point | eBay
One input, balanced/unbalanced in/out, 256 volume steps: Douk Audio 256 Step Attenuator Volume Controller RCA/ Balanced XLR Stereo Preamp | eBay
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Stepped attenuator
Stepped attenuator: (could negate primary purpose for Audient iD14 – namely volume/mute control).
FWIW, original "workshop" PC on-board Realtek direct line out powers the M1 relatively well; minimal audible distortion, no way near max volume…. grabbing for mouse scroll volume far less than ideal… Audient volume/mute knob much preferred.
In lieu of a Stepped attenuator, perhaps a 10K, 10-turn Bourns poti: adjust until acceptable signal is achieved… turn off, disconnect and measure from poti pin 1 > 2, 2 > 3… set up resistor values as voltage divider… for Fixed attenuation…. Volume control with Audient (functioning both as Burr/brown USB DAC and volume control) – (not necessarily stuck exclusively on Burr/Brown: just picked up over time on Internet, B/B is generally preferred.)
…OR… give up on Audient usefulness: Find PCIe (x16 or x1) low profile desktop internal sound card and external attenuator/preamp-Volume control (as with your recommendation – the Douk Audio unit) with correct output for M1 Amplifier input.
(Desktop (SFF) has both PCIe x16 and x1 slots available)
…OR… as the “workshop PC” has no soundcard (to date), external USB DAC “soundcard”w/volume control, with Correct RCA output for M1 Amp.
Footnote: current “home” workstation (vs. “workshopPC"): ASUS Xonar D2x > TOSLINK > Oehlbach D1C6064 (TOSLINK – power via USB) > Kenwood Basic C1(preamp/volume) > Basic M1 amp…. Everything wunderbar...
At Workshop (i.e. not home); damn Basic C2 preamp incompatibility with M1 threw a wrench in the works… Audient iD14 “pro audio output (XLR/TRS)” was not a simple solution.... nor was it cheap.
Goal is to get as much snik/snak off the workbench, (stashed) M1 Amp to speakers, basic volume control(w/mute) on bench, near mouse… all ready too much with o-scopes, lab power supplies, benchtop DMMs, etc.
A simple, basic RME PCIe (x16) soundcard with 1xS/PDIF, and/or 1xTOSLINK, and or TRS output would be pretty groovey… not for sound engineering, just really good tunage (or am I asking too much??)
Apologies for the florid dissertation
Stepped attenuator: (could negate primary purpose for Audient iD14 – namely volume/mute control).
FWIW, original "workshop" PC on-board Realtek direct line out powers the M1 relatively well; minimal audible distortion, no way near max volume…. grabbing for mouse scroll volume far less than ideal… Audient volume/mute knob much preferred.
In lieu of a Stepped attenuator, perhaps a 10K, 10-turn Bourns poti: adjust until acceptable signal is achieved… turn off, disconnect and measure from poti pin 1 > 2, 2 > 3… set up resistor values as voltage divider… for Fixed attenuation…. Volume control with Audient (functioning both as Burr/brown USB DAC and volume control) – (not necessarily stuck exclusively on Burr/Brown: just picked up over time on Internet, B/B is generally preferred.)
…OR… give up on Audient usefulness: Find PCIe (x16 or x1) low profile desktop internal sound card and external attenuator/preamp-Volume control (as with your recommendation – the Douk Audio unit) with correct output for M1 Amplifier input.
(Desktop (SFF) has both PCIe x16 and x1 slots available)
…OR… as the “workshop PC” has no soundcard (to date), external USB DAC “soundcard”w/volume control, with Correct RCA output for M1 Amp.
Footnote: current “home” workstation (vs. “workshopPC"): ASUS Xonar D2x > TOSLINK > Oehlbach D1C6064 (TOSLINK – power via USB) > Kenwood Basic C1(preamp/volume) > Basic M1 amp…. Everything wunderbar...
At Workshop (i.e. not home); damn Basic C2 preamp incompatibility with M1 threw a wrench in the works… Audient iD14 “pro audio output (XLR/TRS)” was not a simple solution.... nor was it cheap.
Goal is to get as much snik/snak off the workbench, (stashed) M1 Amp to speakers, basic volume control(w/mute) on bench, near mouse… all ready too much with o-scopes, lab power supplies, benchtop DMMs, etc.
A simple, basic RME PCIe (x16) soundcard with 1xS/PDIF, and/or 1xTOSLINK, and or TRS output would be pretty groovey… not for sound engineering, just really good tunage (or am I asking too much??)
Apologies for the florid dissertation
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Not at all. A stepped attenuator is a multi-output pad which will allow you to optimise the THD+N of your system whilst maintaining the flexibility to increase the system gain when required. You will still use the i14 for level control and mute.
The ability to increase gain to be able to easily hear low level detail is a critical capability in an audio production suite. The only way you can achieve that is with a variable attenuator on the output of the i14, or what ever other DAC you use. This is not a limitation of the brand of DAC.
There's a lengthy discussion here about optimising system THD+N between a DAC and monitor amp here if you care to wade through it all:
High noise output from PMC Main Monitors due to Bryston Crossover
THD+N
Sir,
many, many thanks for your quick and obviously qualified responses;
however, this may well be over my head, and beyond my modest intentions;
The "workshop" is a classic motorcycle electrics shop...
as an example, my last setup was a Crown Microtech 1200 and E-V SH-1502s...driven by a modest (Heathkit??) mini mixer, cassette tape... even 8-tracks!!
to date, it is somewhat similar: The aforementioned Kenwood M1 (primarily for the "Sigma-Drive" function), driving Tannoy Reveal 6p
... also a collection of Cambridge Audio A1 (3@... should I wander into some tri-/bi- amplification experiments) another pair of Tannoys are available as back up.
With 64 years of sex, drugs and Rock 'n Roll, it is highly unlikely that I would be remotely capable to ascertain the detail to which you allude.
Loud is good, distortion is not only painful, but hard on the gear (AFAIK)
Again, Many thanks,
John
Sir,
many, many thanks for your quick and obviously qualified responses;
however, this may well be over my head, and beyond my modest intentions;
The "workshop" is a classic motorcycle electrics shop...
as an example, my last setup was a Crown Microtech 1200 and E-V SH-1502s...driven by a modest (Heathkit??) mini mixer, cassette tape... even 8-tracks!!
to date, it is somewhat similar: The aforementioned Kenwood M1 (primarily for the "Sigma-Drive" function), driving Tannoy Reveal 6p
... also a collection of Cambridge Audio A1 (3@... should I wander into some tri-/bi- amplification experiments) another pair of Tannoys are available as back up.
With 64 years of sex, drugs and Rock 'n Roll, it is highly unlikely that I would be remotely capable to ascertain the detail to which you allude.
Loud is good, distortion is not only painful, but hard on the gear (AFAIK)
Again, Many thanks,
John
So you just need to buy or make a fixed attenuator for about 12-20dB.
RCA attenuators - Google Search
RCA attenuators - Google Search