MODEL 219 / 2-CHANNEL / 7591 PUSH-PULL AMPLIFIER
MODEL 219
The Model
219 is a moderately priced, two channel vacuum tube amplifier manufactured
using design practices and fabrication methods this designer would want to
see in his own, personal use amplifier. Chassis components, printed
circuit boards and much of the hardware, apart from the output transformers
and a few of the passive components in the circuitry, is manufactured by
suppliers in the USA. The result is a build quality that is remarkable
at this price.
The design practice; offer an amplifier capable of quiet, low distortion output, build it well, measure every design choice and offer it at a nice price.
DESIGN HIGHLIGHTS
- Heavy duty. made in USA, all metal chassis assembly consisting of:
16GA 300 series, mirror, stainless-steel bottom enclosure,
1/4 in. thick 6000 series aluminum top plate, CNC machined, brushed, hard-anodized, dyed matte black,
Passivated stainless-steel machine screws (no sheet-metal screws used anywhere!),
PEM stainless threaded inserts,
Rubber grommets on all chassis pass-through holes.
- Small-signal interconnects:
Amphenol Audio RCA panel jacks,
Alpha Wire 1703, shielded microphone cable for
all connections,
High reliability, solder sleeve terminators for
all shielded cable drain wire attachments.
- Robust, HV solid-state power supply module with Phoenix PCB terminal blocks
and ferrule terminated interconnects.
- Low inductance B+ supply (solid-state supply only).
- Soft start, easy on tubes (solid-state supply only).
- EMI/RFI/noise management:
Filtered/fused AC entry module with red illuminated ON/OFF switch,
Filtered solid-state HV power supply and HV transformer secondary,
Filtered 6.3VAC heater string,
Metal-film resistors in all low power circuits.
All metal chassis, all low level signals shielded.
- Line level, sub-woofer/center channel output with output level adjust.
- Input level adjust for each channel (~1.5VRMS input for 10.8VRMS output across 8 Ohm).
- Stereo balance adjust.
- Heyboer power supply transformer.
- On-board, DC Balance power supply with dedicated transformer tap.
- PC boards fabricated in USA.
- All active/passive components used are from major manufacturers
and sourced from authorized suppliers.
- Powder coated matte black tube cage with thumb-screw fasteners.
- Detachable AC power cord (IEC inlet socket).
- Optional Vacuum tube
rectifier HV power supply.
- Optional Lundahl LL1620 P-P output transformers with powder coated housings.
- Optional Hammond 1650 PAP potted output transformers with powder coated housings (shown above).
- Shipped with Hammond 1650 PA output transformers (powder coated end bells).
- Each channel can be DC balanced "on the fly" without the need to remove the tube cage and pull tubes (digital multi-meter required).
- Tubes: 4x 7591 pentodes (matched pairs), 2x 6GH8 triode-pentodes.
- Amplifier shown with potentiometer knobs removed.
Test Conditions:
- JJ 7591 output tubes
- Hammond 1650PAP output transformers
- 8 Ohm non-inductive power resistor load
(Approximately -3dBV@20kHz all power levels. Blue trace FFT analyzer output loop-back to input.)
The amplifier is available with choice of output transformers and either a solid state or tube high voltage power supply. Amplifier pricing with the output transformer options offered are shown below.
Prices include (4) new JJ7591 power tubes (2 matched pairs) and (2) NOS 6GH8A triode-pentodes.
Model 219 Amplifier with Hammond 1650PA Output Transformers: $2765
Model 219 Amplifier with Hammond 1650PAP Output Transformers (shown above) : $3125
Model 219 Amplifier with Lundahl LL1620PP Output Transformers with Lundahl Powder Coated Enclosures: $3300
Should you be interested in obtaining a MODEL 219 inquire at audio@northreadingeng.com. Note that the amplifier is purchased direct from North Reading Engineering, the manufacturer. There is no reseller mark-up. One final note, for MA residents a 6.25% sales tax will be applied to the sales invoice.
WARRANTY
North Reading Engineering warrants this amplifier product to be free of defects in workmanship and materials for a period of one year from the date of sale. The warranty covers parts and labor. Shipping expense to North Reading Engineering (North Reading, MA) is the Purchaser's responsibility. During the warranty period North Reading Engineering will cover shipping back to the Purchaser unless servicing is the result of misuse such as, but not limited to, operation with shorted or open outputs, mis-clocked tube insertion, wrong tubes, unauthorized service, alteration or physical damage. For amplifiers returned for warranty service, the reason for servicing is determined by North Reading Engineering. Warranty and all rights provided by it are limited to the original Purchaser. Vacuum tubes shipped with the amplifier are covered for 60 days.
SHIPPING
HAND CARRY AND SETUP: For Purchasers within approximately a 4h driving distance from the greater Boston area, the amp can be transported to your location and set up! High quality speaker cables can also be provided. Hand carry and setup provided no charge to the Purchaser.
HAND CARRY: The amp can be transported to within approximately a 4h driving distance from the greater Boston area for transfer to the Purchaser. Hand carry provided no charge to the Purchaser.
STANDARD SHIPPING: FEDEX and UPS shipping to your location.
Tube amplifiers operate at high voltages, the Model 219 is no exception. This amplifier must not be operated without the protective cage fastened to the chassis. Operating the amplifier without the cage fastened to the chassis will expose the user to high voltage shock risk. If you prefer to operate your tube amplifier with the tubes exposed this amplifier may not be for you. In addition to providing high voltage shielding, the cage improves noise immunity and has a measurable effect on the noise floor of the amplifier.