Silverface Princeton Overhaul
We can get your silverface Princeton Reverb sounding and performing better than it ever has. As part of the standard maintenance/tune-up service, we clean all pots, jacks & switches, clean & re-tension all tube sockets, test all tubes, tighten all pots, jacks, switches & transformers, and give the entire circuit an exam.
A full electrolytic recap is often required in original amps. This includes the bias cap, cathode bypass caps in the preamp, and replacing the power filters. The original PR has a 'cap can' housing separate power filters. The modern can replacements don’t meet our standards for tone and performance - they sound terrible (IMO) and are often way out of spec. We replace the cap can with new, individual F&T power filters. This does wonders for tone and performance! We highly recommend removing the can completely and covering the hole with a steel plate (we have these custom made to fit perfectly). The new individual filters fit perfectly once this is done!
As part of the service we dial in the circuit (called blueprinting) - certain key components are replaced if out of spec.
We replace certain resistors that do get noisy over time such as the plate resistors in the preamp, bias board resistor, and power drop resistors in the power supply.
Please keep in mind that CBS era Fender used low quality carbon resistors from mid 1967 - 1969, not the high quality Allen Bradley carbon comp resistors used both before and after this block of time (I suspect they found a huge surplus lot at a very low price). These resistors are almost always WAY out of spec, tend to be noisy, and break very easily when being removed. If you have a 1967 - 1969 Fender, you will need to have the majority of these resistors changed in order to ensure your amp will be electronically stable and sound as good as it can for years to come! This does add both time and parts cost to the service estimate.
If you have a stock silverface, we HIGHLY recommend a signal cap upgrade. It's like taking a wet blanket off of your speaker cab. This upgrade brings you closer to the blackface sound as much as the blackface mod does!
The Mallory M150s are a big improvement over the stock signal caps. The Jupiter “Vintage Tone” series rolled mylar/foil caps are absolutely amazing, and very close both in tone and performance to the classic “Blue Molded” signal caps found in the original Blackface amps.
Popular mods in Princeton Reverb amps include:
Sexy Vibrato: This mod allows a much slower range on the vibrato speed knob! Fast stays fast, but the slow end gets considerably slower. We also make the vibrato effect have a deeper range of intensity. You get deeper vibrato effect available on the knob. VERY useful and players love this mod. If you’re a vibrato fan this is highly recommended.
Adjustable Bias: This easy mod brings your Princeton to another whole level. The PR has a fixed bias circuit, but the bias is determined by a single resistor and not adjustable! This is different from ‘cathode bias’ circuits that bias themselves. With the tremendous range of current draw in tubes these days, being able to properly set your bias is vital for proper performance!! We often find power tubes running very cold or very hot with the standard Princeton reverb fixed bias resistor. We add a mini bias pot allowing the bias to be properly adjusted no matter what 6V6 tubes you install. No drilling!
Standby Switch: Another very useful mod. We convert the obsolete ground switch (with a grounded three prong power cable installed) to a standby switch! Very handy and increases tube life.
Power Tube Resistors: Another great feature that extends tube life. The Princeton Reverb amps were built to be affordable student model amps, and some cost saving practices were implemented as a result. Resistors were left off of the power tubes. These resistors act as buffers and improve the operating conditions of the power tubes themselves, making them much more 'comfortable' in their operating conditions. All larger Fenders are fitted with these resistors. Minimal change in tone (if any), these resistors are more of a performance enhancer.
A speaker upgrade is also a big step towards better tone. The original speakers were 'ok' back in the day (keep in mind that Fender did offer a JBL upgrade at additional cost). These original speakers are often flat and dull now (some 50 years later)! We use Fat Jimmy Vintage Series speakers in our shop. They pair incredibly well with vintage Fender amps and really help bring a dull amp to life! The C1025 is the perfect match for a PR. Highly recommended.
We like to send the player back a blackface or silverface amp that blows away the tone & performance of the amp that was sent in!
I do need to point out that a relatively new 'condition' has been popping up quite a bit lately, where the steel chassis are oxidizing enough to interfere with the ground connection between the chassis and bronze grounding plate under the tone pots and input jacks. I've been needing to remove, polish and clean the plate and chassis and apply contact enhancer before re-installing. This adds about an hour of labor, but it has been literally eliminating hum and other noise issues that may persist after a basic servicing.
We ARE talking about 50+ year old amps after all!!
Shop rates are $100/hour plus parts. A typical complete overhaul takes about 4 hours for a Princeton Reverb, and tends to average around $500 - $700 for the full treatment, depending on condition, upgrades, component quality, tube condition, etc. This estimate allows a new preamp tube or two, but does not include the price of a full re-tube if needed or desired.
Please note that even though the Princeton Reverb is a small, one channel amp, it does take additional time to add many of the upgrades mentioned above such as the adjustable bias, standby switch conversion, power tube resistors, etc. but the end result is well worth it!
After an overhaul, your amp will be good to go for a very long time circuit wise.
Current turnaround time is approx 30 business days.
Please reach out if you have any questions at all!