PAT4 upgrades?

Hello all. I purchased a PAT4 from eBay a few years ago, and it has been a fine user (given my 61 Y/O ears). It came with no history; I have not even opened it up. But I would like to now perform some upgrades. I ran across the below site in Google. The total cost of the four basic upgrade packages (see: DRD4; P4LSCR; PAT4-PWR, and PAT4X) is only $124. Plus another $8 to convert my flickering yellow power light to soft blue.

Have members of the forum had any experience with the supplier, or its suggested changes to the basic PAT4?

http://www.updatemydynaco.com/pat4.html

Winter is coming to the Northeast, so projects are good.

Paul

Paul,
from what I have seen, the UPDATEMYDYNACO boards and parts (and their designs) are very high quality, definitely, recommended.
Since you are posting this on a primarily tube audio related board, let me also say that several of my own boards such as the SP9 and SP12
will also fit into the PAT4 chassis, you would just have to add a new power transformer to complete the PCB kits.
Roy www.tubes4hifi.com/pre11.htm

The changes in UpdateMyDynaco retain the basic circuit topology of the Dynaco PAT-4, and add upgraded parts to the audio circutry and a regulator to the power supply.  They are like taking the engine from a 1965 Chevrolet, replacing worn parts, blueprinting it and installing a new camshaft.

The Van Alstine upgrade changes out the two-direct coupled bipolar transistor gainstage design for integrated circuit operational amplifiers. They are like replacing the entire 1965 Chevrolet engine with a new fuel-injected, computer-controlled one from a 1997 Corvette.  There are now still newer, higher-level upgrade paths but this one junks the old in favor of a completely different, more modern design.

The Van A's PAT-4 upgrade is $799.  That's outlandish.  I am going to give the UpdatemyDynaco guys a try, at one-sixth the price.  

There USED TO BE a complete do-it-yourself construction article in AVA's free Audio Basics newsletter to rebuild a PAT-4 into a "FET-KIT" preamplifier, with all-new, contemporary circuitry.  It had a parts list, schematic and instructions written specifically for the stock Dynaco PAT-4.  AVA has what it SAYS is the complete Audio Basics, available for free download at their website.  However they have DELETED that issue from the downloads!  Those subscribers who received Audio Basics by mail when AVA was sending them out should have it.  Mine are around here someplace, and if I had a PAT-4, I'd dig out that issue and do it myself...at a small fraction of the cost, probably $100-200 worth of parts, perhaps less if I were to raid my infamous junk box!

There was another AVA upgrade article for the PAT-4 a couple of years earlier. It's been deleted from the downloads, too.

Also there was a series of AVA upgrade articles for the Dynaco PAS preamplifier, upgrading it to a Super PAS Three and beyond...and they are now deleted.

I have a PDF copy of the original Van Alstine article from way back: PM me if you want it and I'll try and dig it out. I did the mod on my own PAT-4 but haven't powered it up since.

SungDynaco, I've also been looking at the UpdatemyDynaco website as a way to restart my old PAT-4 project. If you remember to report back to the thread on any experiences you get of their stuff, I'd be most grateful. For the time being, my ST-70 has grabbed my attention.

I've done all of the Updatemydynaco updates for the PAT4 as of a year ago or so. They are an improvement, but the SP9 and complete update of a PAS3X from Mr. Mottram contribute to a more interesting and pleasant sound, in my opinion.

I've also done an Updatemydynaco ST120 in an ST80 chassis. The parts and advice were superb.

I'm in the NE also, ~30 miles South of Bangor. If you're nearby, you're welcome to look and listen to the PAT4.

FWIW:I've done the UpdateMyDynaco upgrades and will vouch for the quality of the parts Nd improvement in sound. Roy's trump 'em all, however.

I also did the AVA Omegastar version. It's good pre with an excellent phono pre. It was a complete rework.

Thanks guys - good to have the feedback on these upgrades.

BTW: There is a vendor on ebay who will do all the updatemydynaco fixes for about $250: payuppal

.

Re-tubing the ST70 got rid of the small amount of noise in the system. But I do want to pull apart the PAT 4, first to see if the previous owner made any changes. For the small amount of investment, and the enjoyment from doing it myself (and living to tell about it), I will order the upgrades, and report back.

Are there any solid state forums that you regularly visit?

Just wanted to revive this thread long enough to report that my Girlfriend kindly bought be a couple of PAT-4 related Christmas presents: all from UpdateMy Dynaco. I got the board kit (line level), the transistor kit (distortion reducing) and the power supply kit. Packing was excellent, and instructions incredibly clear and detailed.

I'll report back with results if anyone's interested: though my ST-70 rebuild will be completed first!

I am very pleased with the results.  I did run into a problem.  Company owner Dan Joffe could not have been more helpful with the diagnosis and repair.  He is a business owner who knows the meaning of great customer service.  Emails were returned immediately, and we did spend a fair amount of time on the phone together.  Dan is a great person to deal with.

The problem was probably my doing.  The aged and fragile PCB - I must have been careless as we found a broken trace leaving me with no left channel.  I had to disassemble and make the repair.  An hour later everything was up and running fine.  

A rookie at this, I got a lot of personal satisfaction from this build.

I found the overall sound to be improved and a nearly complete absence of noise.  I run efficient speakers, which can reveal everything in the background.  I may be tempted to obtain a "test CD", just to see how good things are!

As I've often stated, a most worthwhile and rewarding experience. Kudos to your GF.

pmarcin wrote: As I've often stated, a most worthwhile and rewarding experience. Kudos to your GF.

Thanks! She regards anything that keeps me quiet as a good investment.

Glad to hear that people are having positive experiences from the mods.