Specs on Pilot SA232 transformers?
- Thread starter TroutBear
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are you looking for an exact replacement transformer, or are you looking for modern non-original transformers that are in the ballpark?
Only way to get an exact duplicate in modern form would be to have someone like Heyboer clone it. They would need an original to take apart and copy if they don't already have notes on one.
If you're just after something you can build a 6bq5 push-pull stereo amp around, honestly the transformer set from a Dyna ST-35 is the easy way to go. They exist and the output transformers in particular are pretty good.
Only way to get an exact duplicate in modern form would be to have someone like Heyboer clone it. They would need an original to take apart and copy if they don't already have notes on one.
If you're just after something you can build a 6bq5 push-pull stereo amp around, honestly the transformer set from a Dyna ST-35 is the easy way to go. They exist and the output transformers in particular are pretty good.
@TroutBear
I responded to your thread at DIYaudio. It seems the output transformers, per the SAM's data you posted, are 6k primary impedance. That seems a bit odd for an EL84 PP amp but could be true. Someone that has a real Pilot 232 might be convinced to measure one of theirs to confirm. You certainly could use a more standard 8k transformer for a clone build and it should work fine. There are many good choices at 8k, both new and vintage. You could also find some 6-7k transformers that should work well too if the 6k spec is true. Many of these in the vintage realm were made for 6L6 and 7591 amps.
John
I responded to your thread at DIYaudio. It seems the output transformers, per the SAM's data you posted, are 6k primary impedance. That seems a bit odd for an EL84 PP amp but could be true. Someone that has a real Pilot 232 might be convinced to measure one of theirs to confirm. You certainly could use a more standard 8k transformer for a clone build and it should work fine. There are many good choices at 8k, both new and vintage. You could also find some 6-7k transformers that should work well too if the 6k spec is true. Many of these in the vintage realm were made for 6L6 and 7591 amps.
John
Well, the recommended Thordarson replacement is also 6K p-p. The Triad is 5k (!). But yes, it would be interesting to get some real measurements.
Mike Stehr
Poverty Audio
I have an SA-232 that I reconfigured on another chassis.
I wanted to know the primary impedance of the output transformers and had taken them to a friend who used a B&K impedance/ESR tester of some sort.
He came up with a little over 7K for the primary impedance of each of these particular output transformers that I have...which have seen their share of use.
I wanted to know the primary impedance of the output transformers and had taken them to a friend who used a B&K impedance/ESR tester of some sort.
He came up with a little over 7K for the primary impedance of each of these particular output transformers that I have...which have seen their share of use.
I appreciate all the responses - both here and as a few of you did, also at DIYA. No, I do not have an existing unit - I'm searching for the info to consider building a clone using new transformers [Lundahl perhaps] and premium components. This is after assembling a DG board set ST-35 and being blown away by it in comparison to Mac vintage - mid-60's SS that I still enjoy also. In fact, the pre for the 35 is a Mac C24. I'd now like to explore additional EL84 amps and the Pilot seems to be well thought of. Inputs so far are mostly a bit discouraging, but I do not for a moment doubt their accuracy, i.e unless you have a 2 channel scope and signal generator plus knowledge to understand component swaps to offset not having explicitly the Pilot OPTs then don't bother. Others were a bit more encouraging on not every amp out there is perfectly circuit tuned.
So I'm not sure - to use the Dyna ST35 transformer set as reasonably noted here, I might as well just build another 35 and try a custom chassis with PCB mount spacing wider to allow coupling cap upgrades [Miflex maybe] and splurge on NOS tubes - this is for a 2nd system if you're wondering why not just mod the first one. Kits are are rare these days - the 50's are long gone - but it may simply take stocking a better equipped workbench to try the DIY route.
So I'm not sure - to use the Dyna ST35 transformer set as reasonably noted here, I might as well just build another 35 and try a custom chassis with PCB mount spacing wider to allow coupling cap upgrades [Miflex maybe] and splurge on NOS tubes - this is for a 2nd system if you're wondering why not just mod the first one. Kits are are rare these days - the 50's are long gone - but it may simply take stocking a better equipped workbench to try the DIY route.
Just for the sake of EL84 conversation, you might also consider the Heathkit UA-1/2 and EA-2/3. These are UL PP EL84 amps and they can sound very nice with some restoration and upgrades. I have a pair of EA-2's, which originally were integrated amps, that I converted to be power amps. They were rat rod amps that I got at auction. I removed all the preamp parts, installed a new blank face plate with just a lighted power pushbutton and rebuilt the amp sections from scratch. I added a choke in the supply, installed a better RCA jack on the rear panel, restuffed the can cap, added tip jack test points for monitoring the output tubes, and added an AC balance pot in the phase splitter. I think they sound quite good. I also have an SCA-35 with the full PC board set from DaveG. It's a great little amp, but think I like the Heath's a little better. I prefer separate power amps to integrated's as a rule.
John
John
For the
For the price of a transformer set there's one for sale on a popular auction site right now ripe for restoration. It'll take you all of a day. ;-)
For the price of a transformer set there's one for sale on a popular auction site right now ripe for restoration. It'll take you all of a day. ;-)
Have you compared your rebuild to the stock amps? Was it worth it? Do you have a pics of the inside and/or schematics for what you have done? Tks.
Got it, tks.
One of the reasons I used the EA amps for my project is that the UA's have gotten quite expensive. You can get some EA integrated amps for half the cost of the UA's, maybe less. You just have to be selective about the versions you buy to get matched output transformers and preferably the Stancor versions, EIA code 138. In the end I probably spent nearly as much but I made them my way in some of the details and didn't worry about ruining the value that the UA's command. Many of the EA's are rat rods so you aren't starting with something valuable.
