[MacDEF]

The purpose of this thread is to gather specific, objective, information on headphones amps for an "amp guide." The idea is to gather as much info as possible on as many amps as possible (both current and out-of-production models).

As discussed in another thread, the guide will not include information on sound or quality -- for that info, people will have to use the forums and other sources of subjective info. The purpose of this guide will be to provide a reference to specs/features/etc.

This thread will serve as a place to submit information on various amps. If you have information on a particular amp, please submit it here.

Information needed (please submit in this format):


Picture of amp (both a full-size image and a 70x70 pixel image)
Amp manufacturer
Amp name/model
In production? (yes/no)
List price (final list price if no longer in production)
Current "street" price (used only if no longer in production)
Type of amp (solid state/tube/hybrid)
Stock tubes (only if tubed)
Crossfeed? (yes/no, how many levels)
Other processors? (yes/no, type, details)
Portable? (yes/no)
Power supply (batteries/AC)
Detachable power cord? (only if AC, yes/no)
Number of headphone jacks
Jack output impedance (per jack, if more than one)
Jack output (per jack, if more than one -- include @ #Ohms)
Jack type (mini, 1/4", per jack if more than one)
Inputs (line, etc., how many)
Other outputs (line, pre-amp, speaker, etc., how many)
Speaker output rating (only if speaker out -- include @ #Ohms)
Possible upgrades/upgrade path (tubes, power supply, electronics, etc.)
Housing material (plastic, steel, aluminum, etc.)
Size (dimensions)
Weight


It's OK to post partial information if you don't have everything; hopefully someone else will be able to fill in the missing info. Also, if you post pictures, we'll download them from your post and archive them for use in the guide.

P.S. If there is an obvious information category that I left out, please post that, as well. However, please direct commentary and discussion to another thread, as we will be deleting followups periodically to keep the thread to a minimum.

 

[Hirsch]

David Berning Co. http://www.davidberning.com/microzotl.htm
microZOTL personal amplifier
current model, $750, available direct from manufacturer only
tube amp, uses proprietary Berning OTL design
One 12AX7 and one 6SN7 tube per channel
push-pull Class A, no feedback design
no crossfeed or other processor
power: AC 100-240v, 50 or 60 Hz, or DC 12 v battery rated at 42 amp-hour or better
size of needed battery makes portability problematical
output impedance: 2 ohm (at 0.5 A, 60 Hz)
one 1/4 inch locking phone jack
one set of line inputs (50K Ohm)
one set of speaker outputs: 1 W into 4 ohms, 0.5 W into 14 ohms
Frequency response (4 ohm load): +0, -1 dB 10Hz, 20 KHz, full power
Frequency response (14 ohm load): +0, -1 dB 5Hz-50KHz, full power
Hum and noise: 60uV RMS or 90dB below full output 20-20K HZ
Upgrades: tubes can be upgraded to premium quality for optimum performance, RCA output can be added
Aluminum case with plastic window.
12 in wide, 6.5 in high, 7 in deep (approximately)
weight: 4 lb.

 

[chych]

ASL MG Head DT (NOT OTL):

Picture: http://www.divertech.com/mgheaddt.jpg
Manufacturer: Antique Sound Labs (+Divergent Technologies)
Model: Antique Sound Labs MG Head DT
Production: Yes? Or did OTL replace, I'm not too sure
List Price: $270-$330
Current: ??
Type: Single Ended Triode Valve
Stock tubes: JJ/Tesla 12AX7 and Sovtek EL84 (correct me on ths)
Crossfeed: no
Other processors: no
Portable: no
Power supply: Internal AC
Detachable power cord: Some models
Headphone jacks: 2 (one at a time)
Jack impedance: 10-600ohm (switch)
Jack output: 150mWx2
Jack type: 1 1/4"; 1 1/8"
Input: 2, 1/8" and RCA
Outputs: Just headphone
Upgrades: 12AX7/CV4004/5751/etc Tubes upgraded, EL84/6BQ5/etc tubes upgraded, global negative feedback wires can be removed, can be upgrade to OTL, reversal of plug polarity to remove left channel hum, twist power wires to swtich to reduce hum (if not twisted)

Housing material: Machined steel, ceramic tube sockets
Size: 180x190x160mm
Weight: 4.2kg (~9.24pds)

More info: http://www.divertech.com/mgheaddt.html

 

[joelongwood]

EARMAX PRO

Picture: http://www.audioadvancements.com/hea...phonemain.html
Amp manufacturer: Brocksieper (Germany)
Amp name/model Earmax Pro
In production? Yes
List price: $750 (USD)
Type of amp: Tube. OTL Class A Triode
Stock tubes: 1 X AT7; 2 X 6DJ8 (Brand unknown)
Crossfeed? No
Other processors? No
Portable? No
Power supply: External Power Supply
Number of headphone jacks: 1
Jack impedance: Optimum Load Impedance:>25 Ohms
Jack output:150 mW/ch
Jack type: 1/4”
Inputs: 2 RCA
Outputs: None
Possible upgrades: Tubes
Housing material: “specially developed high insulation unmicrophonic material”
Size: 3.75” W x 3.50” D x 4.00” H
Weight: 15 ounces

 

[fiddler]

CORDA HEADAMP

Photo: http://home.t-online.de/home/meier-a...ontheadamp.gif
Manufacturer: Meier-Audio (Germany)
Model: Corda HA-1
In production? Yes
List price: $325 US assembled; $260 as a DIY kit
Type of amp: Solid state
Crossfeed: "Natural crossfeed filter"; 4 levels (including the "off" position)
Other processors? No.
Portable? No.
Power supply: US version- AC 110/115 Volts; European version- AC 220/230 Volts
Detachable power cord? Yes
Number of headphone jacks: 2
Jack impedance: 0 ohms (right jack) and 120 ohms (left jack)
Jack type: mini (both)
Maximum gain (@ 1 kHz): 12 dB
Inputs: One pair of RCA line inputs
Other outputs: None
Possible upgrades/upgrade path: Power cable
Housing material: Aluminum
Size: 16.5 x 71.0 x 5.7 cm
Weight: 0.6 kg

 

[bootman]

Wheatfield Audio HA-4 Headphone Amp

Amp manufacturer: Wheatfield Audio
Amp name/model: HA-4
In production? No
List price: Never Set. Only five exists in the known audiophile universe.
Street price: about $400 (or whatever you can get on Ebay

)
Type of amp: Solid state w/Burr-Brown OPA134-type op-amps and BUF634 buffers
Stock tubes: NA
Crossfeed? Yes
Other processors? Yes
Portable? No
Power supply: Internal
Number of headphone jacks: 1
Jack impedance: 2.5 Ohms
Jack output: 1W@32 Ohms, 0.5W@600 Ohms
Jack type: 1/4”
Inputs: 2 RCA
Outputs: None
Possible upgrades: Power cord? (TBD)
Housing material: The surface of the HA-4 is covered in 3/8" thick wool felt.
Size: Roughly head shaped

Weight: not specified

Data sheet can be found here in PDF format. (note 526K file)

Moderator: Can you insert my avitar for the 70 pixel pic?
Thanks.

 

[Hirsch]

pic in near future

Grado Labs
RA-1
http://www.gradolabs.com
current model: $350
solid state, dual op amp
no crossfeed or other processing
portable
power: two 9-volt batteries
headphone jack: one 1/4 inch phone jack
one set of RCA line inputs
power: 250 mw
frequency response: .1 dB 20-20K Hz
S/N ratio: 85 dB
possible upgrades: 9.6 volt, 170 mah rechargeable NiMH batteries
mahogany case
5 in wide x 5.5 in deep x 1.5 in high
weight: 12 oz.

 

[robert_cyrus]

Amp manufacturer Rega
Amp name/model Ear (2001)
In production? (yes/no) yes
List price (final list price if no longer in production) £119
Current "street" price (used only if no longer in production)
Type of amp (solid state/tube/hybrid) solid state
Stock tubes (only if tubed) n/a
Crossfeed? (yes/no, how many levels) no
Other processors? (yes/no, type, details) no
Portable? (yes/no) no
Power supply (batteries/AC) AC adaptor
Detachable power cord? (only if AC, yes/no) yes
Number of headphone jacks 1
Jack impedance (per jack, if more than one)
Jack output (per jack, if more than one -- include @ #Ohms)
Maximum output level into 32W load = 525 mW
Input sensitivity for maximum output into 32 ohm = 331 mV
Input level for 250 mW into 32W load = 230 mV
Maximum output level into 600W load = 55 mW
Input sensitivity for maximum output input 600W = 465mV
Input impedance = 24KW
Gain = 21.7dB
Frequency response = 20Hz to 35KHz - 1dB points
Recommended minimum load (normal operating conditions) = 32W per channel
Jack type (mini, 1/4", per jack if more than one) 1/4"
Inputs (line, etc., how many) 1 line
Other outputs (line, pre-amp, speaker, etc., how many) 1 line
Speaker output rating (only if speaker out -- include @ #Ohms) n/a
Possible upgrades/upgrade path (tubes, power supply, electronics, etc.) none
Housing material (plastic, steel, aluminum, etc.) extruded aluminium
Size (dimensions) h 50 x w 182 x d 160 mm
Weight ?

 

[Vertigo-1]

Amp manufacturer: Audio Valve
Amp name/model: RKV MK II
In production? (yes/no) Yes
List price (final list price if no longer in production) $1295
Current "street" price (used only if no longer in production)
Type of amp (solid state/tube/hybrid) Tube
Stock tubes (only if tubed) Polish PCL805
Self-biasing (done individually for each tube)
Crossfeed? (yes/no, how many levels) No
Other processors? (yes/no, type, details) No
Portable? (yes/no) No
Power supply (batteries/AC) AC
Detachable power cord? (only if AC, yes/no) Yes
Number of headphone jacks: Two
Jack impedance (per jack, if more than one) 200-2000
Jack output (per jack, if more than one -- include @ #Ohms) 3W/ch pure Class A
Power Bandwide -- 15 to 100,000 Hz
Distortion -- 0.002%
Damping -- 3600
Jack type (mini, 1/4", per jack if more than one) 1/4" X 2
Inputs (line, etc., how many) Two Line RCA inputs
Other outputs (line, pre-amp, speaker, etc., how many) N/A
Speaker output rating (only if speaker out -- include @ #Ohms) N/A
Possible upgrades/upgrade path (tubes, power supply, electronics, etc.) NOS PCL805 tubes, AC power cord
Housing material (plastic, steel, aluminum, etc.) Aluminum
Size (dimensions) 5.5 * 12.6 * 4 inches (WHD)
Weight 6kg (13Lbs)

 

[morphsci]

Amp manufacturer: McCormack Audio Corporation
Amp name/model: Micro Integrated Drive, MID
In production? NO
List price: $795
Current "street" price: aprrox. $400 - $500
Type of amp: Solid State
Stock tubes: NA
Crossfeed? No
Other processors? No
Portable? No
Power supply: AC, 22V, 500mA Wall Wart Standard
Detachable power cord? NA; See Above
Number of headphone jacks: 2
Jack impedance: 0.2 Ohms, 0.2 Ohms
Jack output: 5W @ 8Ohms
Jack type: Both 1/4" Locking Neutrik
Inputs: 2 Line Level RCA, 20k Ohms
Other outputs: Preamp, RCA, 100 Ohms; Speaker Binding Posts, 0.2 Ohm
Speaker output rating: 5W @ 8 Ohms
Possible upgrades/upgrade path: Power Supply; any unit with 20-24V AC output with min 500 mA. Example is the Radio Shack 273-1690 set to 24V and 1000mA; Electronics revisions through SMC Audio
Housing material: Powder Coated Steel; Brushed Aluminum Faceplate
Size: 9.5"W, 9"D, 3"H
Weight: Shipping 8lbs; Unit Approx. 4lbs
Misc: Absolute polarity is non-inverting; Gain can be set to either +6db, +12db or +26db by the user with internal jumpers.

 

[CRESCENDOPOWER]

Amp manufacturer: Wheatfield Audio
Amp model: HA-2
In production: yes
List price: Standard $849.00 Premium $899.00
Amplifier type: Single-ended, OTL, class A triode amplifier/ single voltage amplifier stage, single cathode follower stage/ DC- coupled input; capacitor-coupled output.
Tube complement: 1 - 6SN7GT voltage amplifier (one section used for each channel) 1 - 6AS7G cathode follower (one section used for each channel) 1 - 5U4G rectifier
Power supply: Full-wave tube rectifier/ capacitor-input filter with choke, using electrolytic polypropylene capacitors/ AC filament supply. Internal power supply.
Dimensions: 13" wide x 8.5" deep x 8" tall (including tubes)
Weight: 13 pounds
Power requirements: 120VAC 60Hz only/ 100 Watts
Fuse type: AGC-type, slow-blow, 1.5A 250V
Output Impedance 100 Ohms
Number of headphone jacks: 1
Maximum output level (1kHz, 5% THD): 620 ohm load is 13V RMS/ 36V P-P. 270 ohm load is 10.5V RMS/30V P-P.
Rated Maximum continuous output power (1kHz, 5% THD): 620 ohm load is 270mW/ 270 ohm load is 400mW.
Voltage Gain: 620 ohm load is 17dB/ 270 ohm load is 15dB
Frequency responce (+/- 3dB) 620 ohm load: 10Hz - 75kHz/ 270 ohm load: 15Hz - 75Hz
Ripple and Noise: less than 3.5mV RMS
Warranty: 6 months on tubes, 1 year on amplifier itself.
Housing material: steel, and wood.
Portable: no
crossfeed: no
RCA line inputs: one set
Other outputs: none
Possible upgrades: NOS tubes, different power cord.
Power cord detachable: yes
Picture: headphone.com
Where to buy: headphone.com

 

[KR...]

Cary Audio CAD-300SEI
CAD-300SEI Specifications
Weight: 51 lbs.
Dimensions: 8" H x 11" W x 14" D
Circuit Type: Single-Ended Class A
Power Output: 15 Watts
Input Sensitivity: 0.42 Volt for full output
Noise and Hum: -90 dB below full output
Frequency Response: 20 Hz to 23 KHz +/- .75 dB
Inputs: CD, AUX1, AUX2, Headphone jack
Tubes:
1 ea - 6SN7 Input
2 ea - 6SN7 Driver
2 ea - 300B Output

Power Transformer(s): 1 ea - EI Laminate, 200% Duty Cycle
Output Transformer(s): 2 ea - EI Laminate, Air Gap, 200% Duty Cycle
Resistors: 1% Metal Film
Capacitors: Oil-Filled Coupling
Power Supply Capacitors: 2 ea - 1200µF@250 VDC
AC Cord: 3 Conductor, Detachable
AC Power Requirements: 117/234 VAC @ 50/60 Hz
Consumption: 107 Watts Operation
Warm-Up Time: 3 Minutes
Break-In Time: 100 hours of playing time
Finish: Black Anodized Faceplate, Chrome Plated Stainless Steel Chassis
Standard with remote control
Retail Price: $4,500

http://www.caryaudio.comn

 

[ai0tron]

MELOS SHA-1

Amp manufacturer - Melos Audio
Amp name/model - Melos SHA-1
In production? NO
List price $1,195
Current "street" price $400 - $500
Type of amp - Hybrid
Stock tubes - Sovteks
Crossfeed? - NO
Other processors? - NO
Portable? - NO
Power supply - AC
Detachable power cord? Only on some later models. Post 93'??
Number of headphone jacks - 2
Jack impedance - .5 ohms
Jack output -
Jack type - 1/4" phono plug
Inputs - 3 selectable line inputs
Other outputs - Pre Amp
Speaker output rating - N/A
Possible upgrades/upgrade path - Contact melos Audio Restoration for details (www. melosaudiorestoration.com). Suggested price/performance tubes = Tesla JJ's
Housing material - Steel case with aluminum front in Black or Silver
Size (dimensions) - 19" Rack mountable
Weight

 

[M Rael]

Apheared 'caffeine' amp
Apheared: "It has a dual 9V battery power supply, a single quad opamp (OPA4134) configured with a gain of 16 and current-boosted outputs. The circuit board just a piece of plain protoboard, approx. 30mm x 40mm (smaller than the batteries), has 6 capacitors and the 12 resistors all standing vertically. The local power supply bypasses are probably overkill with the 100nF caps being 15mm from the supply pins. The LED power indicator is mounted on the top cover (in the penguin's belly). I was going to use a micro 1mm LED for a penguin eyeball, but it didn't look as cool or as "DIY." The power switch is a mini toggle at the back of the circuit board."


NOTE: The guy who designed and built my amp is Apheared, who is also the 'A' in CHA-47 (I'm serious.) Its not a modded 47; it was concocted as a one-off contraption all unto itself.
Heres a thread where he describes it:
http://www.headwize.com/ubb/Forum3/HTML/000801.html

and heres another article (at the bottom of the page)
http://headwize.com/projects/apheared_prj.htm

 

[M Rael]

Amp manufacturer: Wheatfield
Amp name/model: HA-1
In production: yes
List price: $529.00
Type of amp: Single-ended, OTL, class A triode
Stock tubes: 1x ECC82 (12AU7), 2x 7044
Crossfeed: no
Other processors: no
Portable: no
Power supply: AC
Detachable power cord: yes
Number of headphone jacks: 1
Jack impedance: 35ohm
Jack output: 600ohm @ 13V RMS, 35ohm @ 1.5V RMS
Jack type: 1/4"
Inputs: Unbalanced gold plated RCA
Other outputs: 1 pair 'pre amp' gold plated RCA
Housing material: All metal chassis with brushed aluminum faceplate. Fully vented.
Size: 9.5"x4"x7.5