Hi Forum,
A few years ago I got bored with my ARC VT-130 and decided to revoice it after purchasing a Jeff Rowland 625s. Nothing like a new piece of gear to make you dissatisfied with your existing components. That said, I still liked the tube amp and did not want to sell it for something different instead, figuring careful and deliberative changes in parts could elevate the 25 year old amp to a better performance level.
Taking great pains not to change the core sound and performance of the amp (not an easy task) I only made changes to the signal path resistors and its 4 main coupling caps. My goal was to replace the old factory carbon comp resistors of the amp in order to increase its transparency by using modern resistors as well as to increase the soundstage width and depth by changing the amps 4 main coupling caps. After buying practically every boutique resistor Hifi-Collective had in stock, I painstakingly soldered and de-soldered numerous resistors in different locations, burning in each resistor for roughly 400 hours each before evaluating. The whole process took roughly 4-5 months of auditioning until I eventually came upon a combination that delivered the goods. The resulting mod now uses a combination of Shinkoh, Takman REX, Riken RMG, Audio Note resistors and Vcap Odam caps, which together render superb texture, body and transparency not to mention bowling alley deep soundstage performance -- keeping in mind that this is a 25 year old amplifier design. As one forum contributor commented, “the diamond is already cut.’ However, I believe, even an old diamond can benefit from modern polishing equipment and techniques.
I write all this to ask if there was an easier way to burn-in all those resistors out of the circuit, like a cable burner or break-out board of some sort? I settled on soldering in some cut-off resistor leads to the PCB locations, then lightly tacking the different resistors to those leads which made swapping out the resistors much easier. But, I still had to use up precious tube hours in the process. At that time, I only had one set of SED 6550 Winged Cs that was used.
Looking back, I want to slap my forehead for wasting those tubes during the modification. I did consider buying a set of cheap tubes... but I wanted to voice the amp using the tube type I typically use. In the end, I am extremely satisfied with the resulting sound and listen to the amp for several hours every week with joy. Now, if I could only find a really good replacement for the Winged Cs.
