Review: Jolida JD-1000a Tube amp

Category: Amplifiers

I listen to a wide range of music from traditional jazz to prog rock to classical, reggae and folk. Jane Monheit is one of my favorite vocalists as is Loreena McKennit.

What I look for: warmth, easy to listen for long periods, bass extension, imaging, cymbal decay, able to follow bass lines and hear details of instruments.

Sibilance turns me off. I hate it.

I have had the amp for a few days since purchasing it from a fellow Audiogon member. It replaced my Adcom GFA5400 driven by a Little Dot MK III headphone amp used as a preamp.

Wow. My system is now musical. This is a sweet sounding amp. I am using JJ KT77's as output tubes, the original Jolida 12AX7's and Amperex Bugle Boy 12AT7's.

Drawbacks: Only one that I found. The amp is fussy about the 12AX7 tube used. Using some NOS Brimars, there was some high frequency whistling and a hum that varied when turning the volume pot. Also the volume pot sounded scratchy. Having built tube circuits, I figured that the input tube was putting DC on the pot, which tends to have this effect (the input tubes on this amp are direct coupled). Changing out to the original tube resolved the issue. The circuit appears to be SRPP at the input, so it is possible that Jolida did not elevate the heater supply on this tube, meaning that the Brimar did not like the heater-cathode voltage and behaved in an odd manner.

Strengths: the amp sounds great from top to bottom. Not as much high end roll off as the TAD-1000's and much better defined and extended bass. Midrange is just as sweet as any EL34 amp I've had. Sibilance is not exaggerated.

Weaknesses: biasing is not for the faint of heart.

This amp is a bargain.

Associated gear
Keces DA131 DAC with OPA604 op amps
Denon 2910 Universal Player
Squeezebox Touch via coax
Von Schweikert VR-1 speakers
APC mains regulator/filter used on source conmponents.

Similar products
TAD-1000 mono blocks
Jolida 102B
Ming Da 34A
Other tube amps I have repaired for folks
Adcom GFA5400 with Little Dot headphone/preamp
biasing is not for the faint of heart? Please tell us how so..thanks and enjoy the great find.
Bias points and pots are on the pcb between and behind the power tubes. 1. They get hot 2. There are high voltages nearby. You need a steady hand, plastic screwdriver and long probes for the multimeter.

Added info: build quality is great for the price. Better than early Cary stuff.
The factory subwoofer mod is useless as it is high impedance straight off the 100K pot.
With the popularity of these amps and their smaller cousins I am
amazed that not one of the "professional" modders fixes the issue with floating the heaters up in the SRPP first stage.