Fender "Custom" Vibrolux Reverb eventually got rid of the hiss

[guavajelly]

I bought the amp from a friend like 10 years ago mainly to get a nice blues tone at the edge of breakup. I always loved the tone and it's not too heavy (round about the same as a deluxe reverb – approximately 20 kg). Cologne jazz guitar player Joachim Schönecker used one too and he told me that was on recommendation from Peter Bernstein.
Yet that amp always had a prominent hiss that bothered me when playing more subtle genres jazz. There are some common modifications but I hesitated 'cause these would alter the tone (?).
Last week a friend (we formed a band in 1987) told me about a guy that got rid of the hiss in his Vibrolux so I called him. Forward a couple of days I got the amp back. He brought the hiss down from 45mV to 7mV just by changing some tubes.

He wrote me exactly what he did:

• changed both input stages and post reverb ampification tubes to 12AY7
• changed phase inverter to 12AT7

He also changed all "Netztteilelkos" (sorry, I don't know the english term) but I understand that that was due to their age and leakage (?). Sorry, I'm not that tech-savvy.

The amp sounds great and the hiss is down to what a Twin, Deluxe or Jazz Chorus produce. He told me that it also should have a bit more headroom – I will see as soon as we can gig again.

I think that's a simple change everyone that uses this amp could easily try so I wanted to share.

[Ray175]

Glad you found a solution - it can be frustrating when a you have hiss like this from an otherwise great amp since it can discouarage you from getting the most out of it.

Netzteilekos - power supply capacitors?

[guavajelly]

That's probably the right translation. Thanks.
I don't know much about these things so luckily I found this guy. I was trying to sell the amp because of the hiss (and because we can't gig anyway). My friend saw the add and told me that he has the same amp and that guy did it for him.
If anybody in my area (Köln, Germany) is interested I'm happy to share the contact via PM.

[TOMMO]

Netzteil-Elkos = filter caps if I'm not mistaken. I've got this amp model myself and always heard complaints about excessive hum and hiss. I've never percieved that with my amp, though. But thanks for the tip anyway, I will keep it in mind.

[Sam Sherry]

I've done the Moyer Mods on the Custom Vibrolux Reverb a couple of times -- this pdf has precise details. This brings the CVR over to '63 Vibroverb specs and lowers the hiss dramatically.

Just taking the reverb off Channel 1 and reactivating negative feedback alone turn the CVR into a much less hissy, very toneful amp.