We have done close to 300 of the N-400 mods in the last few years. What a difference it makes for tone and ease of set-up!
The mod is three stage, the reverb mod, the tone mod and filter caps replacement. The audio coupling caps are replaced with tantalum electrolytic caps. These are a very expensive cap compared to the original electrolytic caps in the original amp. The tantalum caps have a warm tone and less mid range honk. They have a smooth top end tone as well. The tone caps are replaced with Sprague Orange Drop caps. The audio opamps are replaced with Burr Brown OP2134PA chips.
The reverb mod adds a very definite sparkle. They only exception I have found is with some of the older 3 springs tank that suffered infestation of rotted foam rubber from the piece inside the tank, place above the springs. I keep the replacement 3 springs tanks on hand at all times.
The main power filters caps (6 total) are all replaced as well and several other filters in other areas of the amp.
All together some 38 parts are replaced. All jacks are checked and cleaned. I also test and clean pots as needed. Reverb harness connections are cleaned and re-tensioned. A special type of anti corrosive is applied to the connections
Finally the amp is reassembled and load tested with a scope and 1000hz tone on a 400 watt load bank. After that it is tested on a shop speaker.
The "Intense mod" is $245.00 and return shipping. I will bill for the final freight to return the amp via PayPal. Any additional repairs are extra and will be billed with the final freight.
note:
Place a piece of cardboard over the chassis area and tape it in place to protect the electronics.
I do not recommend UPS for a complete amp. I would use FedEx. If just a chassis and it is packed very well UPS could be OK.
Please not use any packing peanuts for shipping!!!!!
The mod is three stage, the reverb mod, the tone mod and filter caps replacement. The audio coupling caps are replaced with tantalum electrolytic caps. These are a very expensive cap compared to the original electrolytic caps in the original amp. The tantalum caps have a warm tone and less mid range honk. They have a smooth top end tone as well. The tone caps are replaced with Sprague Orange Drop caps. The audio opamps are replaced with Burr Brown OP2134PA chips.
The reverb mod adds a very definite sparkle. They only exception I have found is with some of the older 3 springs tank that suffered infestation of rotted foam rubber from the piece inside the tank, place above the springs. I keep the replacement 3 springs tanks on hand at all times.
The main power filters caps (6 total) are all replaced as well and several other filters in other areas of the amp.
All together some 38 parts are replaced. All jacks are checked and cleaned. I also test and clean pots as needed. Reverb harness connections are cleaned and re-tensioned. A special type of anti corrosive is applied to the connections
Finally the amp is reassembled and load tested with a scope and 1000hz tone on a 400 watt load bank. After that it is tested on a shop speaker.
The "Intense mod" is $245.00 and return shipping. I will bill for the final freight to return the amp via PayPal. Any additional repairs are extra and will be billed with the final freight.
note:
Place a piece of cardboard over the chassis area and tape it in place to protect the electronics.
I do not recommend UPS for a complete amp. I would use FedEx. If just a chassis and it is packed very well UPS could be OK.
Please not use any packing peanuts for shipping!!!!!
Nashville 400 "Intense Mod"
$60.00 surcharge if entire amp is sent in for the mod! Please send chassis and reverb tank only
$60.00 surcharge if entire amp is sent in for the mod! Please send chassis and reverb tank only
Due to a recent home fire we are not doing repairs or amp mods at this time