A Scratch Build Dlite - Kind Of

[fishy]

I usually hang out on the TW side and have often considered tinkering with something different.

This is an ongoing project but here are a few pics of what it is now. Essentially it is a tubes up DLite with 4x6L6s in mind. There are several tweaks that I may end up doing to bring it inline with recognized tweaked design. No OD entrance network or local feedback network at present.

The cleans to me don't sound to great but I like the OD quite a lot.
The amp is extremely quite.

At this point I have not tweaked any voltages and will look at that next aiming towards more accepted levels.

Issues I had startgin up were low volume (cold solder joint) and a blown fuse with OD engaged. Originally the OD wiring was not shielded at all.
Shielding those resolved that issue..

Any comments / observations are welcome.

Thanks as always to the forum and its members.

[David Root]

Nice clean work! Welcome to "The Dark Side!" Or is it TW that's "The Dark Side"? Depends on your perspective I guess! No matter, we're ALL toooone junkies!

That chassis looks familiar. Whose is it?

[M Fowler]

Fishy nice work and how do you like the D'lite type of amp?

I think that chassis is one of rjguitars isn't it?

[fishy]

The chassis is from RJ along with the trannies and some other stuff.
He is as genuine a person as you could wish to meet and is an inspiration.

I used an Edcor on another project and so it seemed an obvious choice to me. The OT is a big Edcor 100w beast.

From a build perspective, this is the most complicated thing I have tried and I am pleased I did it. The decision to build for 4 tubes was a smart one IMO - the amp does seem fuller in comparison to 2 tubes.

The master volume has been a pleasant surprise because it actually works well. The amp is a different beast to the TW style amps and like most things, it takes a little time to find your feet... I'm definitely encouraged with the amp as it is and can only see it improving from here.

[IcemanB52]

Great work! Here’s a tip heisthl shared with me. Run the plate and cathode leads of V1 and V2 together for about an inch. This improves tone and increases sustain. See yellow and blue leads in attached. Again, congrats on a very clean looking amp. Richard

[Structo]

Nice clean build Fishy.

Iceman is right, run the cathode and plate wires together on V1 and V2.

This is the only amp I have ever heard that advice before but it does help the sustain and tone.

The guys here always preach about the plate voltages on these amps.

I resisted for a long time mostly due to laziness.

But several weeks ago when I built my D'Lator, I messed around withe dropping string.
I have to ask myself, self? Why did you wait so long to take care of that?

It really is the first tweak you should do.

V1 - 190v-200v

V2 - 200v-210v

V3 - 290v-300v Adjust the trimmer so that the input side is around 5-6v higher than the other side.

A good way to adjust it is to turn up the amp on the clean channel so it is quite loud.
Using a single coil (preferably) guitar on the neck pickup, lightly brush the strings with your thumb and adjust for maximum overtones and harmonics.
The sound will lag a little behind the adjustment, I guess because of the coupling caps , so adjust - listen - adjust.

EDIT:
OOPS, I see you don't have a trimmer on the PI.
I used a 10K trimmer on the PI to balance the voltages.

I found when I was done, the input side was right at about 6v higher.

Don't tweak any cap values until you get some hours on the amp to allow things to settle in.

On my amp I ended up pretty much the same as the tweaked layout.

High plates on V1 and V2,
120K/ 110K on V3.

4.7uF bypass on both V1 & V2.

Then the last piece of the puzzle was the Dumbleator.
It really should be considered a mandatory piece of gear with these amps.

It really helps the tone plus you can control compression and gain.
Not to mention my reverb and delay never sounded as good as this.

Happy Tweaking!

[fishy]

Thanks for all the feedback.

I will be visiting the voltages first to drop those down. The trim pot on V3 might also
need to go in there at some point also.

Changing cap values right out of the gate is not something I like to do. Particularly with
an amp I am not that familiar with.

I will review the lead dress associated with V1 and V2 plate / cathode.

As it stands, it has some startup tubes in it. I'm looking at getting the Wined C 6L6s for it but I am still open on the pre tubes. Seems many like JJs in these so that might be the way I go. My experience with JJs in my TW builds were not good but this is a different beast..

Thanks again and I will post more when the time comes.

[dogears]

Credit where credit is due....

Dumble did this with the plate and cathodes. We have discussed it here on the forum at length.

Just sayin'

As for Tom's comments, they are spot on! Pay attention to voltages and the PI!

[Structo]

I have tried the Winged C 6L6 tubes and they are very good for current production.
I bought them at AES and I have never been burned there on tubes so I can recommend them.

I too was surprised at how well the master volume works on these.
After hearing for years that the only good MV is a post PI master, this amp definitely proves that to be a myth.

From whisper quiet to wall shaking goodness, these are a very versatile amp.

[RJ Guitars]

Fish,

Great looking work... and I've also heard the inside story that this is a great sounding amp.

Can't wait to hear see the entire story of this build as it all comes together.

rj

[fishy]

I have looked at the cathode / plate wiring for V1 / V2, installed the trimmer for the PI and the LNF on V1.

The dropping string has been adjusted and the voltages are now more in line with expected. I still need to complete a full voltage chart.

The clean sound has improved significantly with the change in the dropping string. I have not had much success making much of the trimmer in the PI but I must confess to not having tried different tubes yet. The LNF network smoothed things out some more but droppingt he voltages made the greatest difference to my ear.

[Structo]

Yes the voltages are key.

On the PI trimmer, that took me a couple times to get that.

At first I didn't realize that it takes a second or two for the adjustment to be heard.
So you just have to slow down and make small adjustments and listen.
Remember to have the volume up quite loud and listen for bloom and overtones. At the right spot it will seem more alive.

Not sure what you ended up with for plate resistors on the PI but I have tried the 82K/100K, 100K/110K and 110K/ 120K
I like the 110K/ 120K with a 10K trimmer.
It just seemed to feel and sound better.

Another thing l liked is the Pre-OD entrance mod which consists of a .05uF cap before the 220K resistor then to the OD trimmer.
I think all the mods on the Tweaked Layout are good ones.


Glad you are making progress. It took me over a year to where I am happy with my amp.
But I was a bit green on tube amps when I built it.

Oh and I put a OD trimmer pot on the back panel to allow adjustment to that on the fly.
I put it in one of the speaker jack holes.

[fishy]

Thanks for the feedback.

The PI is 82k/100k right now but I plan to look at playing with that. Not before I find my feet with what I have though.

Same goes for the pre-OD network although the link on my board is underneath and will be a complete PIA to get out. I probably would have installed that topside had I thought about it a little more in the beginning.

[dogears]

Why would you build a Dumble clone and then use values that he never used? Just curious....

The PI is 82k/100k right now but I plan to look at playing with that. Not before I find my feet with what I have though.

[Structo]

Thanks for the feedback.

The PI is 82k/100k right now but I plan to look at playing with that. Not before I find my feet with what I have though.

Same goes for the pre-OD network although the link on my board is underneath and will be a complete PIA to get out. I probably would have installed that topside had I thought about it a little more in the beginning.

I had the same problem with that under board wire.

The latest two accessories I have bought is a nifty little inspection mirror combo that also has a strong magnet on it.
It telescopes out to about a foot long.
Or just a plain dental mirror works as well for looking under the board when you aren't sure if a wire is right or wrong.
The other was a dental pick tool that can be used for tensioning tube sockets or grabbing loose under board wires.