Hello! And a quick question for any Fender Deluxe Reverb custom owners...

brucegill

Hi guys New to the forum, so, ah, Hello! Just purchased a Custom Fender Deluxe Reverb '68 after taking back a BJ3 that I wasn't happy with. Problem I have, once I got the amp home it has a very audible "hiss". Nothing plugged in, volume right down. Tried various plugs in the house, lights off, phones off, speaker cable in and out etc.... No differance. I'm sure it wasn't that noticable in the shop, but tricky though as there was another guy testing an amp out at the same time. It does however sound bloooody lovely (forgetting the hiss!) Any help or advice would be great. The shop is great, so no worries about taking it back. Would rather find a fix though as its THE sound I was after. ATVB Bruce

Richardj

I have a '68 Twin, there is a bit more general noise than I was expecting but I gather these aren't the quietest of amps, electrically.

brucegill

Thanks For the reply Richard. I can probabley get used to it, but have seen a few mentions of issues on the web. Just tried unplugging the RCA lead from the reverb unit, but not much differance....

ICBM

If it hisses with the speaker cable out, the noise is not coming from the amp!



Assuming that's not what you meant, does it still hiss with all the controls turned down to zero? If no, find out which ones bring on the hiss and report back. If yes, try removing V4 - next to the reverb transformer on the side nearest the power valves.

brucegill

ICBM said:

If it hisses with the speaker cable out, the noise is not coming from the amp!



Assuming that's not what you meant, does it still hiss with all the controls turned down to zero? If no, find out which ones bring on the hiss and report back. If yes, try removing V4 - next to the reverb transformer on the side nearest the power valves.

Hi there. Sorry, I wasn't very clear was I. Speaker cable out, no noise. Speaker cable back in, then I get the hiss. Give me 5 and I'll pull the valve out All controls to 0 and still have a hiss. Thank you!

brucegill

ICBM said:

If it hisses with the speaker cable out, the noise is not coming from the amp!



Assuming that's not what you meant, does it still hiss with all the controls turned down to zero? If no, find out which ones bring on the hiss and report back. If yes, try removing V4 - next to the reverb transformer on the side nearest the power valves.

Ok, looking at the back of the amp, I pulled the 4th from the right, so the one to the left of little transformer. NO HISS!!! It's a GT-ECC83-S What's this valve do?

brucegill

Also noticed after putting this valve back in (get the hiss again) I get a loud pop when the standby switch is switched off. I do have a JJ ECC81 or a Svetlana 12AX7. Either of these compatible?

ICBM

The 12AX7 is. But first, put the original one back and remove V2 - the middle one in the three to the right of the reverb transformer.

These two valves are the first and second (V2) and third (V4) gain stages for the Vibrato channel. The other half of V4 is the reverb return amplifier. You need to know if the noise is coming from the V4 stage or the V2 stage.

brucegill

V2 removed and still have a hiss. V4 swapped out to the Svetlana 12AX7 and I still have a hiss.

ICBM

Sounds like it's coming from the amp circuit related to V4. Unfortunately what I was expecting.

Half of this stage amplifies the reverb return, which is still at quite a low level so the direct signal is cut by a large amount before being mixed with the reverb and then both are re-amplified by the other half of the valve to about the same level as before. The level cut components (a very high value resistor and a small cap) can be prone to causing noise. Any noise from the reverb is also amplified twice. It's also after the channel volume control so it's essentially wide open at this point.

Does the reverb control or the footswitch affect it at all?

brucegill

Thanks for the great info.

No real difference with reverb on but tremolo then effects the hiss with its pulsing.

Guess that I need to take it back? I know a good amp repaire place near by but a bit loathed to payout more

Alternatively I learn to live with it, but it doesn't seem right.

Can't find a schematic for it either.

ICBM

Yes, the hiss is coming from before the tremolo circuit so it will be modulated by it.

Might be worth taking it back and comparing it to others in the shop, in case they vary.

The amp circuit is very similar to the '65, but with some minor changes - unfortunately the schematic doesn't seem to be on Fender's website yet so I'm not 100% certain what they are. With the Princeton it's nothing more than a change in the midrange voicing and a different speaker, as far as I can tell.

Does the reverb and tremolo work on both channels on the Deluxe? If so it's worth pulling V1 as well as V2, I forgot that! I'd still guess it's from the V4 area though.

brucegill

Thanks mate. I did just call them and he just said they are noisy Amps. Hard to hear in a shop with loads going on. May be worth checking against others though, as you say. Yup, both channels have reverb and tremolo will try v1 and v2. Got to nip out with the kids now and the wife looks like she's eaten a wasp after I mentioned I wanted to head over to the guitar shop again lol Thanks again for all your help mate. ATVB Bruce

Babones

It seems almost every thread on forums talking about the 68s, mention varying mounts of hiss (mostly the Deluxe, not sure about the Princetons. Do they hiss too?).
It seems a bit poor really, but then Fender appear to keep putting out amps with faults eg SS 22 channel switching, Custom Vibrolux hiss, 68s hiss etc. I'm considering a Fender type amp and the 68 Princeton is one of the options, but personally, hiss is a deal breaker for me.

brucegill

ICBM said:

Yes, the hiss is coming from before the tremolo circuit so it will be modulated by it.

Might be worth taking it back and comparing it to others in the shop, in case they vary.

The amp circuit is very similar to the '65, but with some minor changes - unfortunately the schematic doesn't seem to be on Fender's website yet so I'm not 100% certain what they are. With the Princeton it's nothing more than a change in the midrange voicing and a different speaker, as far as I can tell.

Does the reverb and tremolo work on both channels on the Deluxe? If so it's worth pulling V1 as well as V2, I forgot that! I'd still guess it's from the V4 area though.

V1 and V2 made no differance, still a hiss. So looks like it's all about the V4 circuit. I'll try and get up the shop during the week, if they have another in stock. Will also call Essex Amps to see if they know of a problem/fix. It's such a shame really. It sounds fantastic and I don't really know what else I would choose if this doesn't work out. Will updat here if I find anymore info.

tone1

I was mega keen on a Supersonic 22 in blonde but all the ones I tried hissed like a bag of snakes which I hate. I don't mind a bit of o'naturel single coil hum but the hiss was so annoying.

MattFGBI

The '68 has quite a bit more gain than the '65 and therefore does have more background noise.  

If you're using the amp with a band or at a decent volume you shouldn't really notice it.  However, at low volumes at home it will be more obvious. 

Teat it against another and see what you think.  It might just be a noisy valve if it's a particularly loud hiss. 

brucegill

MattFGBI said:

The '68 has quite a bit more gain than the '65 and therefore does have more background noise.  

If you're using the amp with a band or at a decent volume you shouldn't really notice it.  However, at low volumes at home it will be more obvious. 

Teat it against another and see what you think.  It might just be a noisy valve if it's a particularly loud hiss. 

Thanks Matt I'm popping to the shop tomorrow (Peach) Just a thought (can't find the schematic for this model anywhere), seeing as when I remove V4 and the hiss stops completely, can this have something to do with the power valves? I've not gone near those. As I've said, apart from the hiss, it's an amazing sounding amp Thanks B

ICBM

MattFGBI said:

The '68 has quite a bit more gain than the '65 and therefore does have more background noise.

Does it have less/no negative feedback, like the Custom Vibrolux, or is the gain increased earlier in the circuit? I'm guessing the latter if the hiss appears to be coming from V4 which is before the NFB loop, but sometimes lack of NFB does odd things...

p90fool

Babones;482716" said:

It seems almost every thread on forums talking about the 68s, mention varying mounts of hiss (mostly the Deluxe, not sure about the Princetons. Do they hiss too?).

It seems a bit poor really, but then Fender appear to keep putting out amps with faults eg SS 22 channel switching, Custom Vibrolux hiss, 68s hiss etc. I'm considering a Fender type amp and the 68 Princeton is one of the options, but personally, hiss is a deal breaker for me.

The Princeton doesn't hiss, as ICBM says it only has a couple of simple cap and resistor changes.

I wonder whether people who've modified older Deluxes so that the reverb is shared by both channels have also ended up with more noise. Could it be that causing some kind of hissy gain structure change?

Re the schematic, Fender takes years to get them onto their website, but if you email Jeff Bielke at Consumer Relations he'll get one to you pretty quickly.

brucegill

p90fool;483316" said:

[quote="Babones;482716"]It seems almost every thread on forums talking about the 68s, mention varying mounts of hiss (mostly the Deluxe, not sure about the Princetons. Do they hiss too?).

It seems a bit poor really, but then Fender appear to keep putting out amps with faults eg SS 22 channel switching, Custom Vibrolux hiss, 68s hiss etc. I'm considering a Fender type amp and the 68 Princeton is one of the options, but personally, hiss is a deal breaker for me.

The Princeton doesn't hiss, as ICBM says it only has a couple of simple cap and resistor changes.

I wonder whether people who've modified older Deluxes so that the reverb is shared by both channels have also ended up with more noise. Could it be that causing some kind of hissy gain structure change?

Re the schematic, Fender takes years to get them onto their website, but if you email Jeff Bielke at Consumer Relations he'll get one to you pretty quickly. [/quote]


Thats a good point re any older DR's that have been modded....

Would you happen to have Jeffs email address?

Many thanks