Smaller Leach Amp V1

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I'm having trouble finding C21 and 27 - I have found up to 8,200 uf/80V in a 2 pin snap in, but not 10,000. I know, close enough. Tried the usual US suspects, digikey, mouser, newark, allied. You either get 4 pin snap ins or smaller capacitance.

I hate to recommend parts connexion because of their high prices, but if you want big snap in caps they now carry 12,000 uF and 15,000 uF and these are on " sale" for around $11.00

http://www.partsconnexion.com/catalog/CapacitorsElectrolytic.html

there are tabs on the bottom of the page- click the one that says new old stock elna dubilier

Apex Jr just got some in (I had a recent purchase of something else and Steve told me about this). Check about halfway down the page.

http://www.apexjr.com/new.htm

10,000 uF, 63V for $1.50 each.
 
Jacco,

Yes, CD 15000uF/80V, but price just went up $6, so it is $65.

Anyone else?


And the order for the leach boards was placed a few minutes ago.
I did the addition again, 192 pcs (not 198 pcs), this is the first time that I did addition wrong ever. :bawling: But I did order 192 pcs though.
 
Finally

Hi, All,

The boards were ordered today. The lead time is 4 weeks and takes 1 week for delivery. Then the boards will be package appropriately and ship to their respective owners. Shipping time will vary depending on location.

I know everyone would like to have them yesterday. So please be patient.
 
JEA capacitors sells 25 pcs for $59 + shipping, 15000uF/80V, Anyone wants to share some?

While I did not recommend JEA capacitors, I have bought from them recently-- the big computer type, not this type.

Anyway, you can just call their number on the ebay marketplace like I did and order directly- no minimum order.

Also note- they quoted me $50 PER CAPACITOR for the ones I wanted and I said that I was thinking $30, and they immediately matched my price.

So yes, this is a good source. Got them on the west coast in a week.
 
The lead time is 4 weeks and takes 1 week for delivery

So i can go another 4 weeks for vacation...
I am back in town and got wet eyes from reading all the posts from the past 3 weeks. But at the end there is not so much news except that the boards are not made in europe.....
Hope it is the same quality as Jens boards.
Greetings, Loek
 
Speaking of those CD 15000uF/80V caps, here's what I'm planning to use...

crcrc.jpg


I picked up 12 of these from JEA as well...they should make a nice CRCRC for the boards :cool:
 
Hello everybody.

I was wondering how many of you would use separate regulated suply for the frontend of the amp.
I was thinking that the reason the frontend had a smaller supply voltage was in order to not "latch" the power transistors when clipping occurs because only the VAS would clip. Of course this reduces available voltage swing therefore efficiency.
If R2R is the target that means the frontend voltage would have to be raised in order to reach VCEsat in the output transistors. This could lead to latching in these transistors.

The frontend could be suplied by such a voltage that it wouldn't quite reach VCEsat and therefore not latch the output to +/- rail and provide optimum voltage swing/rail voltage at the same time. Of course this depends ont the PSU ability to maintain rails under various loads.
(if one would seek only the benefits of regulated supply, then the frontend voltage should be smaller by some amount than the rail voltage under the worst load possible).

I guess the frontend voltage should be only 3-5 volts larger than power section voltage. This can easily be done experimentally.

Any thoughts ?
PS. sorry if this was discussed somewhere else :wave2:

Cheers
 
jondoe said:
sorry if this was discussed somewhere else

Sigh!

If the locomotive of a train brakes i'd think everything behind it does too.
I do not see the need to put loudspeakers on an amplifier that can drive it into clipping.
Even if it does, i'd favor it if only the last wagon hits the brakes.
If its you, you could add a clipping indicator led.

Here's the circuit of the classis Accuphase P102, again.
B1 voltage rails for the front end and the driver is 45vdc
B2 for the output is 20vdc.

Though this one uses Mosfets, J76/K213 for the drivers, and K389 for the entrance, they only need a few volts extra to open up.
Notice that the driver gets the full 25 volts difference.
FTR: regulation need not mean putting higher voltage on the front end.
 

Attachments

  • p102 schem.jpg
    p102 schem.jpg
    86.2 KB · Views: 511
OK. Thanks.
Sorry for putting it like that :guilty:
This was more like a hypotethical situation. Clipping is clipping, no matter where it comes from.
I have some small trafos and will use them for frontend regulation.
I just wanted to hear some opinions.

Again, i'm :guilty:

Jonny
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.