Tight/Loose Switch--Worth the Effort?

[David Root]

I just finished the power supply for my next 183-type build. The board I'm using is designed for two F&T 220uF/300V axial B+1 plate caps in series. In order to get the equivalent of the two 330uF series caps in 183 I had to piggyback a pair of Xicon 100uF/350V in parallel with the two F&Ts. See pic. Cannot find a 330uF/300V axial cap anywhere.

So I guess I could use a DPST switch to disconnect and reconnect the two Xicons, moving between 165 uF (tight) and 110 uF (loose).

Aside from the metaphorical implications of such a switch, is it going to show any differences in tone/feel between the two positions? Is it worth the effort?

[ToneMerc]

IMHO; I don't think it's worth the effort because really, how "loose" is 110uF anyway. To me the switching function would mean more if you could actually switch between truer loose (40-50uF) values and the super stiff 165uF value supply. Also, if the four caps don't all have the same ESR characteristics aren't you shooting in the dark anyway?

TM

[dreric]

"he who shall not be named" from Malaysia has AXIAL 330uf @ 400V for $3.50 each. I just got 10 shipped for the minimum shipping charge of $15.

They appear to be, new, high quality, grey (not orange) and are branded with the "holy grail". Same size as IC 220's, They fit on Jason's boards!

No wars here please just passing on a supplier!

Eric

[David Root]

Thanx for the input folks. I think it's not worth the effort.

I just looked at "that" website, didn't see anything about any parts, let alone 330uF/400V axial caps.

[wicker]

I think that more noticeable effect would choke/resistor switch, just my 0.02$.

[talbany]

Dave I hope you are good!!
Rectifier type of sag can be emulated artificially in an amplifier with a solid-state rectifier by adding a series resistance, typically around 100 ohms or so.. ......Be aware if you switch it in with the amp on it might pop at you so I would do it with the amp off..BTW..I think Weber does this with their copper caps!!

Good Luck!!

Tony

[dogears]

Why not just use radials?

Tons of 300s and 330s available. And Dumble used them too. 183 has radials and not axials!!!

Reinventing the wheel here......

On another note, you guys should know that Dumble had measured and marked the capacitance of the mains on 183 and they were 297 and not 330. 300mf is what is effectively in there.

Since you are being "exact".

[diagrammatiks]

50uf or so is not going to make any difference in feel if it's between 110 and 160.

10 to 60 sure, but as you have it, it's not worth the effort.

You have four electrolytic caps in there right now doing series parallel?

not sure if that's the most effective way to do that. As tonemerc said, if they aren't all sharing the loads equally, and behaving the same it's a moot point anyway.

[Chris333]

Might be more interesting to switch from 165 to 50. I'd think you'd notice a difference. Probably not good for high volume/big-signal power chords, but if you're noodling around at low volume it might be kinda fun.

I'm guessing those are rectifiers north of the plate supply caps. What are they? Is that one of Jason's boards? Looks nice...

[ampdork]

http://www.westfloridacomponents.com/RE ... 7-M90.html

Perfect for homebrew 183's. Cheap too.

Adding to what Scott said regarding 183. I got readings of 303uF and 307uF on those caps. Chalk that up to different tools, time and things being in or out of circuit.
The marked esr however .... big drift up with regards to those readings...that's another story.

I think it would be a little shortsighted to think a 15uF difference is going to make or break an amp. If anyone has a 183 that is not happening for them I feel safe is stating it is not a 15uF +/- putting it off.
But if anyone really wanted to go that route the above caps are probably a good source for buying a bucket of them and sorting through for the "just exactly perfect" values...

[ampdork]

Oh and yes the original had radials with extended leads and gooped down to the board
Witht he board ytou havce there you could drill four small holes, stand the caps up on end and extend the leads to the eyelets. Maybe a small dab of glue to keep them firmly planted.
I never found axial's in that value...there are some caps out there in this value that run about $80 a pop new!! I think Dumble stole it out of some 80's European thing or other. This value seems more common across the pond then in the US ;O)
Wasn't there also someone here selling other blue sprague very close in value and voltage not too long ago?

[Fischerman]

The Bogner Ecstasy has what I think they call the Excursion switch that just plays with the NFB. IIRC, it uses a typical 100k NFB resistor as the tightest position and then adds 220k in series with the 100k for another position and the loosest position has a 1M/470p combo in series with the 100k. Or something very close to that.

[CHIP]

Wasn't there also someone here selling other blue sprague very close in value and voltage not too long ago?

I think it may have been '67 Plexi.

[67plexi]

David, I'm building some 150 watt boards. It's going slow.

What I'm using is BCH Aerovox UK made radials 330uf @ 400VDC.

On the 100 watt #183 build I used 220uf @ 350VDC RDE Germany Axal.

HAD did use 220 uf @ 350 VDC on some 100 watt EL-34 builds.

The leads are larger and had to drill larger holes on the PS board.

I still have some of the large Spragues 330 uf @ 350 VDC USA made.

But would have to be mounted on the chassis to large for under chassis

Mounting using Jasons boards.

I think the 220uf will be fine but you can mount a pair of 330uf radials on

the side with flying leads and glue down like HAD did.

[ER]

Check out the two-rock Eric Gales signature, it uses 2x100uF with the precision supply and El34's.

I wouldn't call it "loose".

http://www.youtube.com/watch?v=9a8I2or1UQk

HRM+Single coils too!

-ER