Zany Laney mania - good link

[Mark Hammer]

Someone on Ampage posted a link to the Laney tech support archive:  http://www.laney.co.uk/html/Downloads/blt1384.htm

A real treasure trove of schems for amps, mixers, preamps, etc.  Easily 150-200 products there.

While looking through schems of some of their lower power amps, I couldn't help but be struck by how often 4069UBE invertor sections were used for gain stages, not only in the dirty channels but in ostensibly "clean" channels too.

Anyone have any experience with any of the solid state Laney amps in the under 60W range?

[AL]

FANTASTIC !!!! Thanks for the link. Sorry, no experience with SS Laney's but I did recently play a 50W tube and I was impressed with it.

AL

[gez]

Anyone have any experience with any of the solid state Laney amps in the under 60W range?

I used to have a little Laney 10W practise amp in the late 70s/early 80s.  Had a nice warm sound to it and was fairly quiet compared to other trannie amps of the day.  Can't remember the name though (Mighty something or other?).  It bit the dust when, in the interests of experimentation/science, I plugged the headphone jack into the input jack... :oops:

Also had a Laney 'Trucker' PA (very loud and punchy for 100W!).  Due to the white script-type font on the panel the Trucker looked remakably like F*cker (someone had a sense of humour)...especially when a mate took some tippex to it!

[gez]

While looking through schems of some of their lower power amps, I couldn't help but be struck by how often 4069UBE invertor sections were used for gain stages, not only in the dirty channels but in ostensibly "clean" channels too

Can you remember which models/ranges you looked at Mark?  I've scanned quite a few schematics now and haven't come across a single one with the 4069 chip (sod's law).  I don't have Broadband so all these PDFs are driving me nuts!  

[MR COFFEE]

Thanks, Mark!!!!!!!

How'd you find that site? :?:

[Mark Hammer]

Can you remember which models/ranges you looked at Mark?  I've scanned quite a few schematics now and haven't come across a single one with the 4069 chip (sod's law).  I don't have Broadband so all these PDFs are driving me nuts!  

Yeah, sorry about that.  The two I'm staring at right now are good examples: the L50R and LGC30/50 preamp.  There are some others though, too.  I've essentially been downloading almost anythng with a number under 80 in its model number.

As for the link, I "found" it in a thread over at the Ampage amp forum where dual 6V6 amps was being discussed.  Someone mentioned Laneys and someone posted the link.

Some interesting tube/op-amp hybrids there, and plenty of units where there are little circuit fragments of interest.  For instance, the various amps with analog chorus use an MN3207 and a CD4046 for clocking.  It provides a nice example of how to tap the signal path, run it through a modulated delay and then combine it back again with the altered signal path.

[RobB]

Anyone have any experience with any of the solid state Laney amps in the under 60W range?

Yes I had two Linebacker 65Rs which I used to patch into each other to effectively form a 2*12”, 4 channel rig when I played in covers bands.  They did a scarily good impersonation of valve amps.  The clipping is accomplished with the 4069 chip.  

I had looked into using the preamp as the basis for a stomp box by taking a line out to the input of another amp, but the EQ didn’t sound right using it this way.  I came to the assumption that there might be further EQing in the power amp section and gave up on the idea.  

These things sell really cheap second hand and make ideal practice amps but beware, there where two versions made.  The first lot with blue and orange screen printing sounded very good.  The second lot with the white screen printing sounded very bad/unusable.  

Now that I have a schematic I might take a second look at it.  I don’t yet know which version schematic I’ve just downloaded though.

Thanks for the link.

[gez]

Yes I had two Linebacker 65Rs which I used to patch into each other to effectively form a 2*12”, 4 channel rig when I played in covers bands.  They did a scarily good impersonation of valve amps.  The clipping is accomplished with the 4069 chip

The Linebacker was the first schematic I looked at as I used to use one on a regular basis (though it wasn't mine).  Yes, the overdrive was very good!  Couldn't find a 4069 on the schematic though so perhaps they did different versions?

Thanks for pointing me in the right direction Mark.

[Mark Hammer]

To the list of those using a 4069 hex inverter chip as gain stages, you can also add:

the BC30 (http://www.laney.co.uk/html/Downloads/Services/BC30.pdf)

the EA65 (http://www.laney.co.uk/html/Downloads/Services/EA65-II.pdf)

[gez]

To the list of those using a 4069 hex inverter chip as gain stages, you can also add:

the BC30 (http://www.laney.co.uk/html/Downloads/Services/BC30.pdf)

the EA65 (http://www.laney.co.uk/html/Downloads/Services/EA65-II.pdf)

Much appreciated!  

Also the PL50R by the look of things:

http://www.laney.co.uk/html/Downloads/Services/PL50R.pdf

I'm going to have to print some of these off and peruse them over the Christmas break.  I always fancied using CMOS for the clean channel of an amp, then if you do get clipping at least it will sound musical!  

[puretube]

free information sucks...

[radio]

I checked my laney lc15r schematics and it s all tube!!

To be or not tube E.

JME

[gez]

Gez: take a peek here, too: http://diystompboxes.com/sboxforum/viewtopic.php?t=28024
(though not CMOSsy...)

Don't worry Ton, I snagged that one earlier (many thanks Stephen)!

Just how many versions did EH do?!  :shock:

[RobB]

Couldn't find a 4069 on the schematic though so perhaps they did different versions?

At first Laney made a big secret of the use of the 4069 by sanding the numbers and blanking out with permanent marker pens.  I took the permanent marker ink off with metho, between the two amps I had I could piece enough of the writing together confirm that it was the 4069.  
The PR1 on that schmatic is the 4069.

[gez]

The PR1 on that schmatic is the 4069.

Ahh, thanks for clearing that up Rob.  It doesn't surprise me at all that the Linebacker used this chip as the overdrive was very valve like, as you mention.

[stm]

I noticed the schematics using a CD4049 all have a potentiometer to set the biasing.  I wonder if the purpose of the potentiometer is to set bias for maximum symmetry, or to set it to some controlled and well defined amount of assymmetry.

On many other CD4049 designs there is usually a fixed high-value resistor from the input to ground (1Meg - 2.2 Meg), as can be seen in ROG's Double D and 3-legged Dog.

I wonder also where did the values on ROG's designs come from:  best sound?  some application note?  some previous design?

Also, take notice the Red Llama doesn't have any ground resistor.

Mmmhhh... Need to experiment with these and listen how it sounds.

[puretube]

Just how many versions did EH do?!  :shock:

there`s probably only one person to know that...

but at least not as many versions as the (Big-) Muffs!

[gez]

I noticed the schematics using a CD4049 all have a potentiometer to set the biasing.  I wonder if the purpose of the potentiometer is to set bias for maximum symmetry, or to set it to some controlled and well defined amount of assymmetry

Well spotted!  There are voltages on the schematics.  For both channels of the Linebacker the 4069s are run off 5V, courtesy of that zener, and the outputs are at 3.35V, so this suggests they were after some asymmetry.

[gez]

For both channels of the Linebacker the 4069s are run off 5V, courtesy of that zener, and the outputs are at 3.35V, so this suggests they were after some asymmetry.

Hmmm, not too sure about this now.  The second inverter stage is directly coupled (no cap) so it might just be that the trimpot is correcting any offset this creates and is not there to provide asymmetry.  

I don’t know about the 4069, but the 4049 often biases up slightly off-centre, so perhaps the trimpot is there to get a more 'symmetrical swing' (or at least closer to what it normally is when biased as a linear amp), though 3.35V does seem a little off from where you’d expect the inverters to bias up at (from a 5V supply).

[stm]

Well spotted!  There are voltages on the schematics.  For both channels of the Linebacker the 4069s are run off 5V, courtesy of that zener, and the outputs are at 3.35V, so this suggests they were after some asymmetry.

I downloaded the Linebacker schematic and finally saw how the CD4069 was getting its power.  At least on other 5 schematics I had seen before there was no specific indication on the actual supply voltage getting in the CD4069 (ahem... or should I say PR1 instead?).

This is the schematic to which I am referring, and I assume this is the one Gez meant:
http://www.laney.co.uk/html/Downloads/Services/Linebacker-50R-65R-100R.pdf

Nevertheless more questions/comments arise upon this:

1) Please notice the use of two PR1 IC's labeled IC2 and IC4 respectively, where one CD4069 would have sufficed for the job since a total of 4 inverters are used.  Power dissipation perhaps? (remember both IC's are operated in the linear region, i.e. more dissipation, instead of the usual cut-off operation).

2) Also, one of the biasing pots (on the upper channel) is connected to +15V, where the lower channel biasing pot is connected to +5V.   Components on both channels are identical, and so are biasing voltages--3.35V.  Perhaps this was a drawing error or another attempt to make cloning harder, like naming the CD4069 as PR1 Laney instead.  Also, never draw the inverters as such, but as a rectangle box with pins scattered all over, thus you won't tell from the drawing which device they are.

3) It is interesting to notice the first and second inverter gain stages are DC coupled, instead of the usual interstage capacitor coupling.

4) And last, but not least, notice there are no high-frequency reduction capacitors across the inverters (usually in the 47-100pF range).  Moreover, the first inverter stage has a 2x47k resistor + 4n7 capacitor network that effectively increases high frequency content instead! Quite the opposite to the Double D or the Red Llama circuits...

There is a lot to learn and experiment from these circuits.

Regards,

STM.