pix of Custom built guitar amps/cabs

[Perrow]

A (chain of) clothes store had amp cabs in their window a few weeks ago when I walked past. When I walked past the second time I thought, hmmm... those would make perfect project cabs, so I went inside and asked if I could perhaps have one or more of those when they'd taken them down. They said "well, we're not allowed to ... but it seems a shame to throw them away. So as long as you don't use them for advertising we'll let you have some, how many would you want?" I could only reply "how many would you let me have?". Well a few days ago I picked them up. Here they are.



They're actually quite nice. MDF boards for sure, but quite sturdy. Here's the front panel for the little kind.



And the large one.



An inside shot.



I reached in to the cabs when they were in the shop window and could feel that there were in fact pots behind the knobs and that the on/off switch could be flipped, promising i thought.

As it turns out there were pots. I've just opened one large and one small, the large one had all C50K (reverse log, that is) pots and the small one had all C20K pots. So if someone knows a bunch of projects using reverse audio pots I'm interested to know about them

The on/off switch looks as a real switch (haven't tested it yet), but the jacks were the big surprise. I kind of expected them to be mono jacks as I thought they'd stuff the cheapest possible stuff in there, turns out I was one for two.



WTF!

They have actually bothered to find jacks without any connectors at all  Well, at least I have a bunch of spare nuts.

I've actually managed to mount a speaker and a Marshall 8010 curciut in one of the small cabs (were actually in the process of building one when I first saw these cabs in that shop window  ), no pictures yet, I'll post those when I've taken them. Sounds good, the control panel needs to be pinned down a little to stop the distortion that it gives right now, but on the whole I'm more than satisfied with the result.

[Ben N]

Heh, heh, great score.

[Dr.maligno]

SLO-50

[Leston Braun]

Finished this one last summer; "Anglia", 2x10" combo, 6V6 power tubes, Marshall-style circuit, high/low input selected with push-pull volume knob. PPIMV master volume.

[Tacoboy]

Just finished: a Marshall JTM45 clone... Completely noiseless and completely hum free... Sounds superb!





My Marshall Dream Stack...  Oh man, it's just the ultimate sound... Blows out my windows and pisses my neighbours off 



And a VOX AC15 clone (with top boost) as well... Needs some tweaking (sounds a little too screamy imho).

[BillyWhizz!!]

Finished this one last summer; "Anglia", 2x10" combo, 6V6 power tubes, Marshall-style circuit, high/low input selected with push-pull volume knob. PPIMV master volume.

Well done... Love the use of an old Anglia badge. I to considered using a car logo and was thinking along the lines of old triumph badges. but your anglia badge hits the spot . javascript:void(0);

[JacktheRiffer]

SLO-50

Where did you get the boards?

[BillyWhizz!!]

A bit of fun for my Amp.

.https://www.youtube.com/watch?v=qwMphcEOCVk

[Earthscum]

As it turns out there were pots. I've just opened one large and one small, the large one had all C50K (reverse log, that is) pots and the small one had all C20K pots. So if someone knows a bunch of projects using reverse audio pots I'm interested to know about them

Tone Controls!!! The reverse taper is perfect for Rat and SWTC's. 

[amptramp]

About a decade ago, I modified a Traynor YVM-1 for Christine, a girl my daughter used to hang out with.  It had one output 6CA7 tube that was arcing and glowing blue from being gassy and it was going to be $37 if I could find one.  Christine was not willing to spend that kind of money, so I came up with a solution.  I redesigned the output stage to use sweep tubes.  The pimout was the same except that the plate (pin 3) on the 6CA7 was not used and would be connected to a plate cap.  I also had to drop the screen voltage since sweep tubes are high-perveance low screen voltage beam power tubes normally run at 150 volts and redlined at 200 volts and the 6CA7 is a straight pentode.  I used brute-force screen regulation - a string of five 1N5363 30 volt 5 watt zeners are shunt regulators.  (A VR-150 would have looked spectacular but there was no place for another tube socket.)  I used 6BQ6GT tubes with the expectation to upgrade to 6DQ6B's and I acquired a fruit basket full of sweep tubes (about 20 of them including the necessary 6DQ6B's) but the opportunity never arose to make the switch.  Word came back that the amplifier is still doing well although she isn't using it that often.  The added plate caps look totally butch and the output should be about 25 watts and this could grow to 35 watts with 6DQ6B's.  The 6DQ6B has an increase in transconductance proportional to the increase in current and both tubes use the same bias voltage, so the swapover could be very simple.

If she ever brings it around again, I might take some pictures.

[davent]

Hello,
From the sublime, amps pictured above, to the ridiculous, Ruby with PRR mod- ipod input, works well, sounds just like ah...
Rescued the 386 from an old baby monitor.








dave

[slacker]

Amp in a can ^tm

[Perrow]

Hey it's a tube amp 

Btw, that 5W resistor feels a bit overspec'ed 

[artifus]

it's the tesco value battery that makes all the difference

[deadastronaut]

it's the tesco value battery that makes all the difference

now thats class A mojo......


@davent: re:PRR mp3 mod: was that using the 2x100k's into pin 3 then?.

[davent]

it's the tesco value battery that makes all the difference

now thats class A mojo......


@davent: re:PRR mp3 mod: was that using the 2x100k's into pin 3 then?.

Hi Rob,

Two x 100k into pin2 (-ve) in my schematic, pin3 to ground. I originally had 22k's there (like PRR had first posted) and then read of the problems another poster was having with too much volume from the mp3 player. I'm finding the 100k's attenuate too much for my ipod, i should have breadboarded the circuit first and found the best value for those resistors in my setup, i imagine the original 22k's would have been fine. So it goes...

In any case a cool little setup, great for using when trying to be consderate of others in the household, bonus is sounds shockingly good to my ear, using it with a cheap reverb pedal is a treat. Totally surpassed my expectations. Now need to get some more 386's so i can sample the various other iterations of these chip amps. Fun...

dave

[deadastronaut]

@dave: cool, ill check that out thanks,  i need to build a little amp for camping this year...

i'll try n squeeze the amp into a 1590a (mini head) and then have a speaker out  so i can try various speakers and see which one i like best....cheers.

[davent]

Perfect, you'll have no problems with the 1590A, the 3pdt is the space hog in those builds and you don't have to worry about squeezing one of those in there.

Take care
dave

[birt]

Ampeg B15n, single channel.
Front:

Back:

In:

Guts:


it was quite a challenge to adapt this circuit to an amp that has a more unusual layout.
i'm thinking about adding some more graphics on the sides and top.

[Perrow]