New amp

[LeftyStrat]

Dave, did you use standard values for the power supply caps? I've wondered if one could get away with lower capacitance with the low ESR caps, while retaining the same feel.

[Colossal]

Dave, did you use standard values for the power supply caps? I've wondered if one could get away with lower capacitance with the low ESR caps, while retaining the same feel.

I used the Dr. Z version with 40uF - Choke - 40uF, but 22uF (run in parallel off the screens) for the preamp filters. I also included 220k bleeder resistors, one on each of the two 40's. In a parallel arrangement as I used, I could have gone much, much lower on the capacitance since the R value is high. There is no ghosting in this amp.

As far as feel goes, I think you could lower capacitance to retain feel of a classic amp, but that might not be too big a deal (depending on the amp). I think this would be most apparent in a power supply application. I opted for the Dr. Z version values of the Rocket power supply for the power amp and it feels fine. I saw no need to put 80uF on the rectifier as in the real Rocket design (although it is fine in this case as the rectifier is not operating near its AC voltage input limit or current supply capacity limit).

I would not say that this amp feels spongey or "slow" but it is not hard and brittle either like some amps that are over filtered. It just sounds like a very loud, natural sounding AC30 with that kind of yelling-into-a-coffee can, clanky piano but gorgeous tone. The depth of the amp is great and it blossoms into sustain so easily with higher gain preamp tubes. When you get the amp up to 1pm and beyond, it really opens up. It goes from the polite Voxy cleans into the more focused higher gain sound, almost Marshally in a way (not EQ but musicality). You can really hear a beautiful chirp on the pick attack (especially in the 10th to 14th fret region on the high B and E strings).

I think one of the nice thing about those polypropylene caps is their transparency. You just hear the circuit voicing and your guitar, no clutter or blurriness. The Sozo polyester "smear" on the edge of the note and clarity is still there. It sounds almost like a horn for lack of a better description. The low end is full but not boomy. I have some 1x12s made of 3/4" BB with a dadoed 3/4" baffle. They are intentionally built like tanks and I have a couple loaded with EVs. The sound of just one of these cabs and an EV just blew away every Celestion speaker in every other cab I have. No sh!t. Way more of everything. And I've been a Celestion man for 20-some years.

[dcribbs1412]

Fantastic looking build Dave
Thanks for the cap info and new inspiration.

Darin

[Milkmansound]

wow - really interesting to hear about those poly caps.

I may have to try them! They are not cheap - but are probably worth the extra money in the long long long run.

For one of my amp models, these would make a lot of sense. Not much bigger than the Atoms, but higher voltage ratings mean less of them. I wish they made an axial version, but every Wima cap I have ever seen/used has been in that giant orange box with the tiny short leads.

[Colossal]

Fantastic looking build Dave
Thanks for the cap info and new inspiration.

Darin

Thanks Darin!

wow - really interesting to hear about those poly caps.

I may have to try them! They are not cheap - but are probably worth the extra money in the long long long run.

For one of my amp models, these would make a lot of sense. Not much bigger than the Atoms, but higher voltage ratings mean less of them. I wish they made an axial version, but every Wima cap I have ever seen/used has been in that giant orange box with the tiny short leads.

Give'em a shot man, you might like them. I think from the business/longevity side, they make a lot of sense. Plus I like the very high voltage ratings available. They do sound good to me. I hear you about the lack of an axial format but most everything these days is for PCB applications. Guys like us preferring axial formats for the obvious convenience with turret board construction, well, we're probably considered as obsolete as our amps to part designers

[statorvane]

That is a magnificent build. Really first rate. Hats off to you guy!

[Colossal]

That is a magnificent build. Really first rate. Hats off to you guy!

Thanks!

[stephenl]

How did you attach / solder the Wima's? Did you just put the short leads into an eyelet and solder from underneath? I thought about trying a similar box cap (Epco) but wasn't sure of a good method to provide a good mechanical/electrical connection on an eyelet / turret board.

[Milkmansound]

Give'em a shot man, you might like them. I think from the business/longevity side, they make a lot of sense. Plus I like the very high voltage ratings available. They do sound good to me. I hear you about the lack of an axial format but most everything these days is for PCB applications. Guys like us preferring axial formats for the obvious convenience with turret board construction, well, we're probably considered as obsolete as our amps to part designers

do you think the leads are long enough to mount the cap on its side and wrap them around turrets?

I think they would be a great match for my Milkman Pedal Steel amp - which I like to have as rigid a power supply as possible because that is right for steel players.

I am seriously considering trying a set and putting them into my personal steel amp. Only thing is they are just a hair too big for a fender chassis if they are mounted onto my turret board. I will have to wedge them in there somehow, or heaven forbid, put them under a doghouse.

[Colossal]

How did you attach / solder the Wima's? Did you just put the short leads into an eyelet and solder from underneath? I thought about trying a similar box cap (Epco) but wasn't sure of a good method to provide a good mechanical/electrical connection on an eyelet / turret board.

Yes, they are soldered to eyelets. The leads are very short however, something like 1/4" (6.4mm) since they are for PCB mounting. I used a blob of silicone (low acetic acid) under the cap as there is a tiny cavity between the outer plastic shell of the cap and the potting which seals it. The silicone dampens vibration as well as gives some added surface in contact with the eyelet board. Next time, I will move the eyelet centers so the leads just fit inside the rim of the eyelet. More of the eyelet would be exposed, making it much easier to service the joint later if needed.

do you think the leads are long enough to mount the cap on its side and wrap them around turrets?

Double turrets, barely/partially. Single turrets, yes, but you would need to be creative and careful with how you bent the lead around the turret. They are malleable but want to bend at the base, not the tip as would be needed to start the arc around the turret. A fine needle nose might help to bend it right around the post in situ.

[Comanche]

That looks so cool. WoW
I would love to plug into that for an hour of fun.

[rp]

I love big chunky parts, it what got me into tube amps.

[Colossal]

That looks so cool. WoW
I would love to plug into that for an hour of fun.

Thanks man!

I love big chunky parts, it what got me into tube amps.

Yeah, seeing that battery of Solen's in Davent's amp reminds me of a bandolier of M40 grenades. Looks awesome

[dorrisant]

Wow Dave! That looks amazing... I had tried the Wima type caps on a preamp build and have been contemplating the cost vs benefit of trying them throughout an entire amp. Glad to see your build... did I miss any sound clips? I would love to hear it.

Love the finish and grill work too! Top notch.

Tony

[Bob S]

Top Shelf all round Dave.
Wima - hmmm.
Must try some.
The bar keeps getting higher!