I have an older Creek integrated amp (4140, ver. 1). It began blowing the AC fuse about two-three weeks ago. I contacted Creek and they told me that the transformer was likely blown. So, I decided to rebuild it somewhat. I analyzed the power supply portion of the cicuit, and looked additionally for capacitors throughout the circuit. I also found some op amps. I definitely wanted to replace all polarized electrolytic capacitors (5).
Here's the stuff I put in:
Power supply:
4 fast recovery diodes $5
2 10mF Nichicon Gold Tune polarized electrolytic caps $9.90
4 0.1uF Black Gate electrolytic caps (across diodes) $7.40
1 250VA, 25V output toroidal transformer $42.26
This is an increase from 2 6.8mF (millifarad) to 2 10.0 mF caps and from 160VA to 250VA transformer. Also, the previous diodes were 3A and the new ones are 4A.
The rest of the circuit:
2 47uf (microfarad) Nichicon Muse polarized electrolytic $1.90 (not sure what these are for -- this part of the circuit is not diagrammed)
1 2.2uf Black Gate polarized electrolytic cap $0.75 (between + and - rails,I think)
2 Burr Brown OPA2132PA op amps $11.00
2 sockets for op amps $1.30
4 0.1uf 5% Rel Cap RT film and foil polystyrene caps $22 (put in signal path from last op amp to speaker outputs.
That's a total of $101.51. This does not count silver-content solder, a new soldering station, solder wick, and -- probably the most expensive thing -- my time for analyze the circuit, find suitable replacement parts, desoldering, resoldering, and analyzing and reanalyzing the circuit to make sure I wouldn't blow anything.
My thoughts on the upgrade/fixing process are as follows. Percy Audio kicks butt and has a ton of stuff of audio-quality. A bridge rectifier, typically shown as a diamond, can look like an X with diodes at the top at the bottom and inside the lines of the X -- something that threw me for a loop for a long while. There are no drawings I can find that tell one how to hook up a toroidal transformer with two primaries and using 115V to create two (+) and (-) rails on two secondaries. I thought I knew how to do this (it seems obvious from the drawing, after I thought about it a while), but I wanted confirmation from a circuit. I searched for quite a long time before I was able to find something that indicated that I was correct, and this was in text. In other words, you can find this:
http://www.aksaonline.com/products/products_aksaasmbly.htmlquite readily, but this is for 220V, not 110/115v. The original 0.1 uF caps used for the output signal were about .25 inches wide and tall and about 1/8 inch thick. The replacement reliable capacitors are 0.42 inches wide by 1.25 inches long! They are massive! It took a while to fit these in. The new diode's legs had to be bent. The pads for the transformer could not be used in order to fit the transformer inside the case. The 10mF caps barely fit. An adjustable soldering station helps this process immensely! You can set it hot when removing solder and cooler when soldering leads for caps. A hair dryer doesn't work for heat shrink (although I did have it on low, mistakenly thinking that low was for the fan and not the heat).
The sound? I am stunned. The output is quite a bit higher for some reason (op amps?), I'd say 20-30 percent higher. So high that I took my 8 ohm bookshelfs down to the HT and brought up my full range Linn, 4 ohm speakers (and Creek recommends against hooking this amp up to 4 ohm speakers). I had it running for hours into the Linns with no evidence of strain or extra heat. The overall impression for me is a much stronger, livelier amp with better bass extension. However, that's not hearing the amp for several weeks, so this may be an invalid test, other than for the power aspect, as I know where I used to have the dial and now the dial is much lower. Oh yeah, after I powered it up and played for about 10 minutes, I put in a Signal Cable power cord (I ordered a 15 amp connector to replace the 20 A connector on the cord so that I could use it with the amp).
This project has me thinking of building an Aksa amp and maybe a power supply (with remote turn on/off, if possible) for my Ack Dack. Such projects are going to have to wait, though, as insulation for the house and running network cable are my next projects.
Pictures are forthcoming.
