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

p90fool

jbielke@fender.com

brucegill

p90fool;483889" said:

jbielke@fender.com

Many thanks!!

MattFGBI

ICBM said:

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...

There are changes in the preamp to the voicing and amount of gain. PM me your email and I'll send you the drawing. 

ICBM

Done!

It's great to have a company with such a sensible attitude to schematics, compared to the nonsense many others go to keeping them 'secret'. It's hardly as if there's much that's very new in valve guitar amplifiers.

brucegill

MattFGBI;484103" said:

ICBM said:



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...










There are changes in the preamp to the voicing and amount of gain. PM me your email and I'll send you the drawing. 

Yes please will send a PM

p90fool

ICBM;484265" said:

Done!

It's great to have a company with such a sensible attitude to schematics, compared to the nonsense many others go to keeping them 'secret'. It's hardly as if there's much that's very new in valve guitar amplifiers.

It's great isn't it? As far as I'm concerned anything which encourages home servicing, experimentation and exchange of ideas is healthy and sensible marketing. It certainly inspires loyalty from customers too.

On a slightly different tack, I always had a bit of a hankering for a modern Triumph motorcycle, but they refuse to release service information, even to a registered motorcycle MOT station and service centre like mine.
Consequently I never bought one, and heartily recommended everyone else to avoid them too.

It's the same with music technology, short-term dealer protectionism tends to lead to early obsolescence IME.

Sassafras

Does that mean you can only take your Triumph to a licensed dealer?

That's a scam. The one near me charges a fortune for everything.

p90fool

Sassafras;484539" said:

Does that mean you can only take your Triumph to a licensed dealer?That's a scam. The one near me charges a fortune for everything.

It's easy enough for anyone to carry out routine servicing on them but when they develop a fault like say, the crank position sensor (which every bastard one seems to eventually) it's practically impossible to get the diagnostic info you need unless you have a "tame" technician who's prepared to risk his job by whispering what you need to know down the phone.

For example, on some models the two connectors should read 870 ohms between them at 20C, +/- 10%, but Triumph don't want you to know this, they want you to diagnose the fault by substituting a new £89 part, and electronic components are non-returnable.

It's a rare treat to see a corporation the size of Fender NOT behave like this.

brucegill

Just get a nice old Yamaha XS650

brucegill

Just to update. Been the shop today, both sounded vertually identical. Vibriolux was MUCH loader.

Thanks for everyone's help, I'm going to keep the amp as it sounds fantastic. Seems the hiss is just, ah, character lol.

It's really not THAT bad but made me worry. Thanks also to John at Peach for being so helpful and patient!

Cheers all

ICBM

If it does still bother you, Matt has very usefully sent me the schematic and I have an idea as to how to cure it, or at least reduce it, without changing the sound of the amp much. It might not be a great idea while it's under warranty, although what needs doing is not invasive.

Basically the negative feedback has been reduced, as I suspected - roughly halved - and with the two channels linked before the reverb there is now no channel mix divider at the output of V4, which will roughly double the level there as well - so there could potentially be around four times as much noise from V4 making it through the power amp compared to the '65.

It should be possible to add a cap and possibly a resistor to the NFB resistor to increase NFB for high frequencies only; and/or add a resistor and cap to ground at the output of V4 to simulate the Normal channel being connected there. The exact values may need some experimentation so as to reduce the hiss without changing the tone of the amp, though - so it's difficult to advise exactly. Something for a tech near you who doesn't mind a bit of trial and error.

bandmaster188

brucegill said:

Just get a nice old Yamaha XS650 

 

yep, great for chopping!

brucegill

bandmaster188;484875" said:

brucegill said:

Just get a nice old Yamaha XS650  yep, great for chopping!

Oh yes! I've hard tailed one of mine (still in bits) and the others just mildly chopped up love them!

brucegill

ICBM;484814" said:

If it does still bother you, Matt has very usefully sent me the schematic and I have an idea as to how to cure it, or at least reduce it, without changing the sound of the amp much. It might not be a great idea while it's under warranty, although what needs doing is not invasive.

Basically the negative feedback has been reduced, as I suspected - roughly halved - and with the two channels linked before the reverb there is now no channel mix divider at the output of V4, which will roughly double the level there as well - so there could potentially be around four times as much noise from V4 making it through the power amp compared to the '65.

It should be possible to add a cap and possibly a resistor to the NFB resistor to increase NFB for high frequencies only; and/or add a resistor and cap to ground at the output of V4 to simulate the Normal channel being connected there. The exact values may need some experimentation so as to reduce the hiss without changing the tone of the amp, though - so it's difficult to advise exactly. Something for a tech near you who doesn't mind a bit of trial and error.

Thanks mate, I'd be interested to hear more. I have the schematic from Matt as well. Not 100% on where you would ad the cap and resistor? Any idea on what id need?

I'm happy with it at the moment but can see me maybe wanting to sort it out. Now I know it's not just mine that's noisy it's less of a issue

bandmaster188

brucegill said:

bandmaster188;484875" said:

brucegill said:

Just get a nice old Yamaha XS650  yep, great for chopping!

Oh yes! I've hard tailed one of mine (still in bits) and the others just mildly chopped up love them!

I had one for short time, not chopped but a mate had a hardtail with a ridiculous set of apes on it. Makes my spine hurt just thinking about it!

brucegill

bandmaster188 said:

brucegill said:

bandmaster188;484875" said:

brucegill said:

Just get a nice old Yamaha XS650  yep, great for chopping!

Oh yes! I've hard tailed one of mine (still in bits) and the others just mildly chopped up love them!

I had one for short time, not chopped but a mate had a hardtail with a ridiculous set of apes on it. Makes my spine hurt just thinking about it!

Lol, I know what you mean. I'm not the talest guy in the world so not sure I need a few inches going when my spine collapses Mega low tire pressures are the way forward!

hotpickups

You've got me looking at them now. Bloody GAS. I can control it though fortunately

Babones

I'm just wondering. The people who complain of hiss on the 2 channel 68s, is it because they are plugged into both channels and both volumes are up? ie turn one down and the hiss goes? (or just plug into one channel only). I think i noticed this on the new Supro amps too, where you plug into the channel 1+2, it gets noticeably hissy, as it has both channel volumes in use. Perhaps someone with a '68 Deluxe, Vibrolux, Twin can respond.

brucegill

The hiss on mine (and the other in the shop, plus a vibrolux) was without anything attached. all knobs set to 0. 

It's not as bad as I've made out to be fair. The overall tone from the amp outweighs the hiss. 

Not tried using both channels together yet. 

I have also read that swapping out a few valves helps. I've ordered some to have a play (Tungsol 6V6GT-P pair and a couple of JJ ECC83S-GP for V1/V2) also waiting on a bias probe so will be a little while before I can report back. 

If I play through the amp above "2.5" on the volume it's not an issue, at "3" you don't notice it at all. Recording may be a pain though.