Jolida modifications

In exclusive partnership with top-tier modification house Parts ConneXion, Underwood HiFi is proud to offer the following carefully tested, factory-authorized performance enhancement packages for Jolida amplifiers,CD players and phono stages.

By virtue of selling consumer-direct, we can offer these super-charged, brand-new models for a better price than the same modifications would cost retro-fitted - though we offer that, too

We are glad to introduce a very high quality affordable tube preamp that will compete with far more expensive designs. Our modified Jolida Fusion remote controlled preamp is better than any $5k preamp that we are aware of. It goes head to head with the Reference series designs from ARC as well as expensive preamps from Modwright, Conrad Johnson and Aesthetix.

New modified preamp $2250.00
Mod to your preamp $1300.00

 

Denon 3800JD-1501BRC Level-1 mod - $1,690 + shipping ($900 retro-fit) Our Level-1 mod installs -Denon 3800 -four large EAR brand sorbothane isolation feet -two sheets of SoundCoat -Russian Electro-Harmonix 12AX7 (2) and 12AT7 (2)
Jolida JD-1000PWe now have a modification to the Jolida JD-1000P power amplifier. This basic EL34 tube amp is an upgrade to the amp section in the JD-1000RC integrated. It adds ultra-fast Hexfreds to the power supply as well as other custom Jolida parts. It also has a set of balanced inputs as well as RCA ins. We really like the stock unit.
JD-1000RC The Jolida JD-1000RC is an upgrade from the older basic JD-1000a. It adds a beautiful new look with a large window in front. In addition, the RC model has remote control as well as a preamp/sub outs, upgraded parts quality and a tape out. It also adds Simple Bias. This new bias system can be done without a meter in under a minute.
JD-1000A JD1000A Level-1 mod - ($850 + freight retro-fit to your unit) -Our Level-1 mod installs -four large EAR brand sorbothane isolation feet -two sheets of SoundCoat
JD 502BJD502B and JD502RC Level-1 mod [$750 retro-fit to your amp] and JD-502CRC [$750 retro-fit to your amp] - this last model adds remote control, XLR inputs, HT bypass, EZ bias and a front panel mini plug input. For all models our Level-1 mod installs: -four large EAR brand sorbothane isolation feet -two sheets of SoundCoat -Russian Electro-Harmonix 12AX7 (2) and 12AT7 (2)
JD302B Level-1 modJD302B Level-1 mod [$750 retro-fit to your amp] and JD-302CRC  ($750 retro-fit to your amp) - this model adds remote control, XLR inputs, HT bypass, EZ bias and a front panel mini plug input. For either version our Level-1 mod installs: -four large EAR brand sorbothane isolation feet -two sheets of SoundCoat -Russian Electro-Harmonix 12AX7 (2) and 12AT7 (2)
JD202A Level-1 modJD202A Level-1 mod [ $650 retro-fit] and JD-202RC Level-1 mod [$1,490 + shipping, $650 retrofit] - this version adds a remote control, top-mounted bias control and a mini plug on the front. Our Level-1 mod for either unit installs: -four large EAR brand sorbothane isolation feet -two sheets of SoundCoat
JD100A Level-1 modJD100A Level-1 mod [$590 retro-fit] - our Level-1 mod installs: -2 x sheets of Soundcoat damping material on internal chassis to damp vibrations -4 x large Ear compliant Sorbothane isolation feet

New Jolida Music Envoy mod New Jolida Music Envoy mod: The Jolida Music Envoy preamp is part of the $9500 Music Envoy pre/power package and Jolida's best preamplifier. It is fully remote controlled and has a very good phono section. The stock unit is a wonderful value at $1500 retail. Our Level-1 and 2 mods make it dramatically better.

JD300B Level-2 modJD300B Level-2 mod - [$3,290 + shipping, $1,500 retro-fit] - Our Level-2 mod installs : -Replacement of the stock input/driver tubes with premium new-old stock Mullard ECC83/12AX7s and NOS mil-spec Mullard CV4003/ 12AU7s designed for 10,000 hour operation - these tubes are ultra low noise with ultra low microphonics

Our design goal was to take this $2,300 amp and make it as good as the competition that sells for up to $8000. Price for the mod was not the issue, performance the only goal. We use only the very best of parts and the end result is an amazing remote-controlled 300B integrated amp that you have to hear to believe. Quoting from its first review, we learn:

New Jolida JD-402 tube tuner modification Jolida JD-402 Level-1 mod [$400 retrofit] - Our Level-1 mod installs -4 x small EAR brand compliant Sorbothane isolation feet -2 sheets of SoundCoat chassis damping material -3 feet of DH Labs 23-gaugepure 99.999% silver signal wirewith foamed Teflon tape-wrap dielectric

New Jolida JD-707 modification
The JD-707 is a new 40wpc Jolida integrated amp that is sonically extremely close to the low-powered sub-10-watt SET amps. Our mod is a major upgrade and allows users to get the gorgeous midrange and sonic reality that these micro-power amps offer but have enough power to drive most real-world speakers.

Jolida JD-707 Level-1 mod - [$650 retrofit] -
Our Level-1 mod installs:

Jolida FX Tube DAC/Preamp MK3 Our Level-1 and Level-2 mods for the Jolida FX Tube DAC/Preamp MK3 take this high-value DAC to the next level. The basic $500 DAC is a great sounding inexpensive tube converter with 3 inputs - 1 x coaxial, 1 x USB and 1 x optical.

JD-700The JD-700 was a quality CD/DVD player with a 2-channel tube output stage. The stock unit was the best sounding, reasonably priced DVD player that we know of for playing Redbook CDs when it was available. The unit also offers balanced outputs for fully balanced systems.
The Jolida JD-9A MK2 is a very good $700.00 phono stage. It has a tubed output stage and rear panel controls for cartridge adjustment. It has enough gain to run almost all moving magnet and moving coil phono stages.
 

JD-9A MK2 Phono Stage Level-1 mod

We still offer mods to the discontinued JD-9a for the same costs listed below as the new MK2 version.

The following details the Level-1 modification for the Jolida JD-9A Phono Stage ($400 + freight retrofit; $990 + freight for new units):
  • We install 2 Auricap signal path metallized polypropylene coupling capacitors. 
  • 8 Riken Ohm ½ and one watt signal pat" 1% carbon comp. resistors with gold-plated leads are installed. 
  • 4r International Rectifier Hexfred ultra-fast soft recovery, diodes are installed in the power supply. 
  • We replace the two stock preamp tubes with a pair of Electro Harmonix Gold pin tubes.
  • We Install 4 small EAR brand Sorbothane isolation feet. 
  • 2 sheets of SoundCoat chassis damping material cut & applied where applicable. 
  • WBT high silver content (4%) solder used throughout. 
  • The mod takes a total of 3 hours labor.
Sonic changes of the Level-1 mod
The unt has a more liquid midrange and more neutral presentation from bass to treble. It is quiter. Blacks are blacker, resolving more low level detail and ambiance. It is more dynamic and micro dynamic contrasts are much improved. Transparency is improved and you can now look farther into the soundstage. Images are sized better and are more defined. Stage width and depth improve.Bass slam and extension are improved with fuller weight and authority in the critical midbass region. It now competes with much more expensive units in this important area.

Our basic Level-1 mod is $990 for new units and offers exceptional value. Our Level-2 & 3 mods take it to the next level and allow it to compete with world-class phono stages that sell for up twice what these modified units sell for. These mods were designed by Chris Johnson, the founder and former president of Sonic Frontiers.
 

JD-9 MK2 Level-2 mod

The following details our Level-2 mod ($1,450 new, $850 retrofit plus shipping):
  • We replace the two stock preamp tubes with premium matched milspec Russian Electro Harmonix gold pin 12AX7s, designed for 10,000 operation. These are ultra low noise with ultra low microphonics. 
  • We add two Auricap metalized polypropylene coupling capacitors in the output signal path 
  • We install four hi quality coupling, bypass and power supply capacitors 
  • Eight Riken Ohm ½ and one watt 1% carbon com. resistors (gold-plated leads) are added in the signal path 
  • Four International Rectifier Hexfred ultra-fast soft recovery diodes are installed in the power supply 
  • One pair of premium Vampire direct gold plated over copper body RCA female connectors on the input 
  • Two additional 1000uF/25V upgraded capacitors are used in the phono power supply 
  • We replace the stock $4.00 Burr-Brown OPA-2604 dual op amps in the output driver section with two adapter PCBs, allowing the use of the world's finest op amp, the $25.00 Burr-Brown OPA-627 single surface mount op amp. W use two modules with 4 opamps in total. 
  • We Install four large EAR brand Sorbothane isolation feet 
  • Two sheets of SoundCoat chassis damping material are cut & applied where applicable to the chassis. 
  • WBT high silver content (4%) solder is used throughout 
  • 4.5 hours total labor

JD-9 MK2 Level-3 mod

In the Level-3, we do the following additional mods to the Level-2 ($1,790 new, $1,200 retrofit plus shipping):
  • Replace four additional $4.00 single op amps with the world's finest op amp, the Burr-Brown OPA-627 
  • We add 10 additional top quality 220uf 6.2V Power supply capacitors 
  • Two more Auricap metalized polypropylene coupling capacitors are added to the input signal path 
  • We install fourTelefunken SF4007 ultra-fast soft-recovery diodes in other sonically critical power supply positions 
  • We replace the stock tubes with RFT (German) 1970’s vintage ECC83’s. (12AX7’s)
  • Total install labor – 6 hours
If you are looking for world class performance at reasonable prices, then these modified units are perfect.
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