Friedman BE 50 advice

[evh_slash]

So I have a new BE 50 which I had converted to Rackmount form. I'm loving it so far but having just a couple of minor noise issues.

1) Is it normal for the bright switches on the CLEAN channel to introduce some hiss / noise floor ??? My mesa Quad preamp / Mark series amps Clean channels are dead silent, even with bright switch on.

I have the schematic for the Friedman HBE amps and the 3 way bright switch just looks like a choice between simple 100pF or 200pF cap.

2) Having it converted to rackmount meant having to install a fan within the amp like a lot of the rackmount guitar power amps or bass amps often have.
The fan itself is of high quality and is not very physically loud HOWEVER, is it normal to be able to hear a subtle drone of the fan noise through the speaker cab ?? It's like it is getting picked up through the amp circuitry / tubes somehow. It is not loud and not that much of a problem but when practising at bedroom volumes I guess it can irritate me just a little just knowing its there. It doesn't increase with different volume/gain settings... its kinda just there in the background drifting in and out. I feel like it starts out almost silent but as the amp is on for longer and warms up more the fan starts to become a little more noticeable.

Any advice or input would be much appreciated. To put into perspective my VHT 290 Power amp has a much louder fan BUT it is only mechanically louder, I can't actually hear the fan noise through the amp/speaker cabs at all like I can with the Friedman. I guess i'm only concerned at the fact it comes through the cab and wondered if anything can be done to minimise this noise being picked up / leaking into the amp signal.

 

[FuseG4]

Re: Friedman BE 50 advice

Simple Bright caps especially on an amp with some gain, will introduce a little hiss that should become much less noticeable as you play. If it is bad hiss that you can't tolerate while playing, then suspect something's wrong.

As for the fan, yeah some amps have a hot preamp and straightforward tone shaping that will let through more noise and vibration sounds, but as for the fan it could be vibrating a slightly microphonic tube, component, or wire.
With the amp on and being careful and using something not conductive, like a chopstick, touch, bump, and lightly tap wires, resistors, caps and tubes near the fan, if anything has a really loud bump sound, or if you hold it steady the fan noise drops, it's likely that the fan is vibrating sympathetically with that

 

[Ayrton]

Re: Friedman BE 50 advice

Have you discussed this with Dave?

 

[Lake Placid Blues]

Re: Friedman BE 50 advice

Does the rack mount conversion have the shielding plate that grounds to the chassis like you would find inside a head cabinet?

 

[evh_slash]

Re: Friedman BE 50 advice

Have you discussed this with Dave?

No I haven't because he'll probably tell me off for modding the amp to fit in a rackmount chassis and I don't want to hear the typical warranty disclaimer. I was just going to query on the forum first to ask what it could be, I may chase it up at a later stage. For now its not a huge deal to me.
As for the bright cap issue I should definitely pop him over a message.

 

[evh_slash]

Re: Friedman BE 50 advice

Does the rack mount conversion have the shielding plate that grounds to the chassis like you would find inside a head cabinet?

I have no idea. I'm assuming so. I didn't perform the conversion! haha My guy knows his stuff so I'm sure he's done it all properly!

Why do you ask ? is that something that could affect the fan / noise ?

 

[evh_slash]

Re: Friedman BE 50 advice

Simple Bright caps especially on an amp with some gain, will introduce a little hiss that should become much less noticeable as you play. If it is bad hiss that you can't tolerate while playing, then suspect something's wrong.

As for the fan, yeah some amps have a hot preamp and straightforward tone shaping that will let through more noise and vibration sounds, but as for the fan it could be vibrating a slightly microphonic tube, component, or wire.
With the amp on and being careful and using something not conductive, like a chopstick, touch, bump, and lightly tap wires, resistors, caps and tubes near the fan, if anything has a really loud bump sound, or if you hold it steady the fan noise drops, it's likely that the fan is vibrating sympathetically with that

Thanks for the fan advice and troubleshooting! I shall check it out when I get a chance.
As for the bright cap however... is it normal even on the CLEAN channel to experience that slight noise ?

 

[Ayrton]

Re: Friedman BE 50 advice

No I haven't because he'll probably tell me off for modding the amp to fit in a rackmount chassis and I don't want to hear the typical warranty disclaimer.

You clearly don't know Dave very well.

I would email him first.

 

[Lake Placid Blues]

Re: Friedman BE 50 advice

I have no idea. I'm assuming so. I didn't perform the conversion! haha My guy knows his stuff so I'm sure he's done it all properly!

Why do you ask ? is that something that could affect the fan / noise ?

Yes, it is there to reduce noise. If it's been omitted, then that could be the problem.

 

[Red_Label]

Re: Friedman BE 50 advice

You clearly don't know Dave very well.

I would email him first.

Exactly. Dave is a tweaking machine and game for nearly anything. If I was going to rackmount one of my Friedmans.... I would have emailed Dave before doing it. But then again... I'd never rackmount a Friedman in the first place. A live-in road case is as close as I'd come to that. To each his own I guess...