Ceriatone Dizzy 30

[playonit]

Thanks guys..... I am probably going to redo the Tolex... the recessed area is not acceptable to me.. I need to find some more in-depth info how to do the recess area curves .. the rest was easy to do including the corners which without the metal corners could stand alone..

[Diablo1]

Compound curves are hard to cover with Tolex and keep from puckering. That's why there are no compound curves on my cabinet. I think you need to make multiple seams and butt them together to avoid the pucker in the curve.

[Structo]

The only trick I've heard of is to gently warm the tolex with a heat gun or hair dryer when trying to make it conform to shapes.
Depending on the tolex, it may not work real well.

Factors such as thickness of the material, backing, glue all play a part.

playonit, that head and cab look real nice together.
I love the maple on the top.

Is the valence/ grill made from MDF or other wood that you intend to lacquer?

[Structo]

Really nice!

FWIW, I just replaced the "Larmar" master with a VVR type circuit that only scales the power tubes and PI. It sounds better because the PI fizz less noticeable (because you can hear the power tubes breaking up too), there's no loss of bass, and no loss of overdrive. Scaling the whole amp was not sounding too good for me when the preamp tubes got down too low.

I will say that the improvement was not much over the Larmar, and it'll definitely be better in the DC30 than the cross-line crap.

Gaz, have you ever tried a boot strapped master volume?

I had a small push pull, cathode biased, 6V6 that was a test bed for ideas and when I was experimenting with master volumes the boot strap was the only one that worked very well or sounded good.

You can do a single boot strap or double boot strapped master volume.

[John_P_WI]

If you use the improved bootstrapped master (the first scheme Tom shows), you don't need to scale the PI.

[playonit]

The only trick I've heard of is to gently warm the tolex with a heat gun or hair dryer when trying to make it conform to shapes.
Depending on the tolex, it may not work real well.

Factors such as thickness of the material, backing, glue all play a part.

playonit, that head and cab look real nice together.
I love the maple on the top.

Is the valence/ grill made from MDF or other wood that you intend to lacquer?

Thanks Tom!! Yes the valence will get paint.. I was thinking Piano Black Lacquer? Might be to much black though.. couple options I want to try for giggles

Cover in grill cloth to match the speaker cab

Cover in a different fabric like paisley and lacquer over that

And thick about another color besides the black?

I got over my fear of tolex on this one.... I have 3 more to do now 2 5e7 and JTM 45 Bluesbreaker...

[Gaz]

Really nice!

FWIW, I just replaced the "Larmar" master with a VVR type circuit that only scales the power tubes and PI. It sounds better because the PI fizz less noticeable (because you can hear the power tubes breaking up too), there's no loss of bass, and no loss of overdrive. Scaling the whole amp was not sounding too good for me when the preamp tubes got down too low.

I will say that the improvement was not much over the Larmar, and it'll definitely be better in the DC30 than the cross-line crap.

Gaz, have you ever tried a boot strapped master volume?

I had a small push pull, cathode biased, 6V6 that was a test bed for ideas and when I was experimenting with master volumes the boot strap was the only one that worked very well or sounded good.

You can do a single boot strap or double boot strapped master volume.

I've tried that before, and it did sound good, but didn't like how messed with the NFB. In this amp that's not an issue, but I imagine it's loose a ton of gain when turned down because so much comes from the PI/power tubes. That's why I went for the VVR. I dunno, I prefer less controls, so scaling the PI/power tubes works well because you only need the VVR control, we at least in this amp.

[Structo]

The only trick I've heard of is to gently warm the tolex with a heat gun or hair dryer when trying to make it conform to shapes.
Depending on the tolex, it may not work real well.

Factors such as thickness of the material, backing, glue all play a part.

playonit, that head and cab look real nice together.
I love the maple on the top.

Is the valence/ grill made from MDF or other wood that you intend to lacquer?

Thanks Tom!! Yes the valence will get paint.. I was thinking Piano Black Lacquer? Might be to much black though.. couple options I want to try for giggles

Cover in grill cloth to match the speaker cab

Cover in a different fabric like paisley and lacquer over that

And thick about another color besides the black?

I got over my fear of tolex on this one.... I have 3 more to do now 2 5e7 and JTM 45 Bluesbreaker...

One thing nice about using grill cloth on that panel is that you can cut some ventilation holes in the panel to allow air to circulate, cooling the tubes somewhat.

[Diablo1]

I decided to play around with Channel 1 to see what is voicing it so bright. I changed the plate resistor from 220K to 100K. That reduces the gain a little, but there is still plenty on tap. It didn't have much of an effect on the frequency response. Then I swapped out the 500pF coupling cap for an 0.022 mfd cap. Bingo, now it has a frequency response similar to a Fender. Give it a whirl and see what you think. If you want it brighter, just reduce the cap value a little.

[playonit]

OK, here's the schematic for the Larmar PPIMV and the layout I used:

[IMG1600]http://i41.tinypic.com/2hftbwp.jpg[/img]
[IMG767]http://i55.tinypic.com/5chveg.jpg[/img]
[IMG1200]http://i43.tinypic.com/minhqt.jpg[/img]
[IMG1200]http://i42.tinypic.com/1zcgx7b.jpg[/img]

Thanks for that... I'll give it a go........

I set mine up today with the Larmar PPIMV ..... so far it is an improvement over the stock push pull.. It definitely helped the harshness/tone and noise in ch/2 and the sound just has an overall smoothness to it compared to stock..

ch/1 seems to now have more gain and a little more darkness which I really wasn't looking to get. I had previously changed the cut circuit resistor from a .0022 to an .0047.... after the addition of the Larmar PPIMV I changed it back to the .0022 and also went back to the pf180 bright cap trying to get some clarity back . the jury is still out on ch/1 for me.

The thing that has me the most perplexed is the MV's hair trigger on ch/2 it goes from 0-1000 with hardly and knob rotation..

For the most part I like how it's smoothed things out on ch/2 and need to figure the volume sensitivity there..

[M Fowler]

You used a 250kL pot on that LarMar right? Should not be responding like you said on Ch2?

I think the MV needs to be connected directly to the .047 caps on the board not through the cut control.

Mark

[Diablo1]

Playonit said: "The thing that has me the most perplexed is the MV's hair trigger on ch/2 it goes from 0-1000 with hardly and knob rotation..

For the most part I like how it's smoothed things out on ch/2 and need to figure the volume sensitivity there.. "
_________________

My guess is you have something wired up wrong from chnl 2 to the phase inverter tube or from the phase inverter to the cut control or MV. Each channel goes to a different side of the phase inverter.

I'm thinking about another mod. I'll re-purpose the speaker reverse switch to switch channel 2's capacitor tone control switch and circuit between channels. That way, chnl 1 will have all those choices for coupling caps as well as treble and bass controls and the cut control. When I plug into chnl 2, I'll flip the reverse switch and the cap tone control switch goes back to chnl 2.

[M Fowler]

We were posting at the same time here is what I edited on my upper message.

I think the MV needs to be connected directly to the .047 caps on the board not through the cut control.

Mark

[Diablo1]

We were posting at the same time here is what I edited on my upper message.

I think the MV needs to be connected directly to the .047 caps on the board not through the cut control.

Mark

I don't think so. Check my schematic above and you'll see that the MV is in parallel to the cut control. It works fine wired up as in my layout. Also, I'm pretty sure I used a dual "Audio" pot for the MV.

[playonit]

On the layout you did... do you have 2 wires connected to pin 2 one going to the front center tab the other going to back center tab on the MV pot?? that's the way I hooked it up.