Mapletree Ultra 4A SE - mods

i had mine modded, by replacing the caps in the signal path and resistors.

My key policy in 35 years of amplifier design is KISS - keep it simple sweetheart.

Removing a potentiometer from the signal path is a help towards that and could result in a noticeable improvement - depending on the quality of the pot - and very few are any good, in my opinion. And as you say, something easily reversable if it doesn't work out.

Changing the wire in an Umbilical cable is not so clear cut, if the amp is designed well it should make no difference as the sonically affecting powersupply filtering needs to be done RIGHT at the actual amp itself, not back at the powersupply. IMO, certainly not worth spending big money on a boutique silver cable. And if you want to try it, why not make a new silver umbilical yourself?

Regards, Allen (Vacuum State)

bypassing the channel level controls?

I wouldn't. Have you tested your channels individually at your listening seat? I tested mine (250Hz; 500Hz; 1kHz) and discovered that the left channel was off by -3dB from the right. Why? Perhaps my room (asymmetrical, different openings left/right side)? Or tubes? Not sure, but am glad I discovered this. And glad I have the individual channel levels on my Mapletree Audio 2A SE Linestage to correct.

You may wish to check this out as well.

Rockadanny, I have channel level control on the MC7200, so I can handle any differences in output that way. Actually, I'll be checking that now that you mentioned it, hadn't thought about it before, and I know for a fact the room is acoustically a disaster.

Re the umbilical cable, I've read and been told by multiple owners of the Mapletree that it makes a big difference in sound. The stock one is lamp wire, and going to silver is a good improvement. I've found VH Audio sells the silver wire, but I'm wondering if there are other sources I've missed.

why dont you consult the good doctor?
I'm sure he will be glad to assist with improvements.

Update, took the channel level controls (pots) out of the audio path. Result: noticeable improvement in overall sound.

Dag! I wish you hadn't said that. Now my upgrade wheels are churning ... and just when I thought I was finally done!

Can you describe the improvements a little more please?

Yes the Revelation umbilical cable makes a hugh difference... so a DIY progect could work nicely. However the power cord does make that large of a change. Also NOS tubes can make a big improvement as well.

Love my 4A SE.
Tony

RE the sound change, I would say I'm getting more air, more detail, cymbals sound crisper.

The "mod" took about an hour but only because I was extra careful.

Umbilical power cable upgrade to silver is next on the list. Still hunting for a better source for the 18ga silver wire.

Has anyone tried to dampen the bottom metal plate? I have Dynamat extreme laying around, but I'd hate to kill the dynamics or dull the sound.