I have a Bedini amplifier that needed to have one channel rebuilt. It took months for that Bedini house sound to return. Be patient.
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My sunfire SRA is predecessor to 300 and needs an attention because it became noisy at idle. So far I've done reapplying a fresh solder to input XLR jacks and to binding posts and all of power transformer outputs. It solved problem partially, but my next step is ongoing to test power-supply caps and replace them. Another culprit of decreased performance quality is actual wear of Tripath chip(very inexpensive itself and very easy to replace) that will need replacement together with provided service(I'm not sure if that was done, but very very likely).
My expectation that I will
1. get rid of humm
2. get some edginess or brightness while tripath chip(that is a logical circuit) will 'adopt' to the output stage for the next 20...50 hours of listening.
3. i don't plan to expect loss of sound detail though and don't know the particular reason for that.
I love the sound of my sunfire 300 and I'm using both current and voltage outputs to the different drivers.
The right channel blew out, so I sent it for repair and told them to also upgrade the electronics. Now, the amp sounds nothing like it did before service. Loss of detail, 3D image was huge and is gone.
Theduke answered my question somewhat, but how many hours is the typical burnin period?
As I understand they've done the job on dead channel and as a matter of fact decided to replace the same elements in the live channel too. As a living studio and stage techie, I would probably be able to take a look at repair project done if you can post pictures of an open box. Output transistors in particular close-up.
Marakanetz...asked the shop for details and haven't heard back from them yet. My invoice says 1).Transistor and fuse blown, rebuild right channel. 2) add caps.
Parts are... 2 output transistors, 10 Caps, 1 fuse.
I assume he replaced the 5 blue caps on L/R channels. Does not say if they are Polystyrene. I'm very glad the stock power supply caps were not replaced.
To update you, it's 50 hours burnin and sounding pretty good. More detail, soundstage has filled in, has that Sunfire warmth. But I'm still missing the deep 3D image that my system should present. I use Amperex NOS in my preamp and CDP and the image should extend way back into the rear wall...that's the best part of my system.
Will keep burning in and wait for details from the shop. Will stay in touch.
That is to say:
They've only repaired one channel and it will take more time before they become identical to bring your soundstage back. Don't worry about blue caps.
To be honest I'd do the same, because it's very easy to screw up parameters on digital amp so it will sound like garbage. To be more consistant, I'd probably test transisor's transients(no worries about the brand either) to match one of the pulled-out live ones and than find the one that mathes or simply get the whole batch of them to replace them all, but it's whole different price point of repairs. I believe that they've matched your transistor, but no matter how precise you are, you'll still have some gaps in parameters to be settled.
that's great news Marakanetz. It would be a shame to replace it since you're happy with your system. I love the Sunfire sound, plus I dont think you could find a better amp for the price.
My amp is also dead quiet since the service...such great build quality and design, it's a keeper for life; just keep replacing parts when needed.
Replacing parts WILL be a great challenge. These amps aren't supported anymore by the manufacturer for long time already. God only knows who possesses schematics as well if the problem will rise more complicated. Assembled boards to replace aren't manufactured either so exercise safety and protect your unit with surge protectors. There are also not too many of them for sale either as they become slowly the legend of hi-def audio.
You've raised some issues I never even thought of.
Roland at carveraudiorepair has cornered the market on all
parts, but when I needed service it was a 3 month wait. On the forums I found out that he has former Carver/Sunire people with him and the schematics and such.
I went to Vintage HiFi in Pittsburgh (an authorized dealer and service for many years). Very nice owner, my only worry is the quality of the parts used.
Yes, they are in great demand. I'm sure you've followed the sales on ebay...they are snatched-up very quickly.
I like the DYI spirit in several of the posts.
Just last month I got tired of dropouts on my two Sherbourn 5/1500A monoblock construction amps, chatted with a friendly tech, ordered $2.50 relays, and using my Xtronic solder gun and air tool workstation, some desoldering wick, and high silver content solder, i replaced all 10 relays.
In the process i removed all connector harnesses and applied electrical contact paste to these and the terminals, dusted the heatsinks.
I have been making sweet eyes at Pass Labs and Classé monoblocks for a while, but the 4 of them would be hard to justify (CP-700 biamps) now with perfect Sherbourns.
I've seen that, but there are much better options here at 'gon for $700.
For those who's not technical, I'd say that it's still a bargain even if you will have to send the unit back-fourth to/from WestCoast to service it.
They sound like class A more than class A/AB/B and they never run hot with plenty of power to drive any speaker and SILENT when no music no matter if you mute or unmute your preamp.