I'm perfboarding an F1 and maybe an F2. Is a 250va 18-0-18 toroidal transformer undersized for a mono bloc for these amp types?
What would be the ideal VA rating?
Thank you!
-David
What would be the ideal VA rating?
Thank you!
-David
Hi David,
You're fine for a monoblock. Some might even consider 2 chans from that transformer.
Graeme
You're fine for a monoblock. Some might even consider 2 chans from that transformer.
Graeme
Thanks guys for the help.
I'm looking at an Avel-Lindbergh Y23 series. They have a 160VA and 250va in 18-0-18 at Parts Express with a free shipping special offer.
They seem like a good vendor and could probably assume the VA ratings are accurate?
-David
I'm looking at an Avel-Lindbergh Y23 series. They have a 160VA and 250va in 18-0-18 at Parts Express with a free shipping special offer.
They seem like a good vendor and could probably assume the VA ratings are accurate?
-David
Avel Lindberg is all right in my book.
The thing about VA vs. Watts is that sometimes it's apples to apples and sometimes it's apples to elephant boogers. Setting aside the relative quality that you might expect from one manufacturer or another, the VA only equals W if the load is purely resistive. Once the load becomes reactive (not to be confused with radioactive), then you get into power factor correction. Depending on how far off the current and voltage peaks are from one another, you can get wildly differing numbers.
Grey
The thing about VA vs. Watts is that sometimes it's apples to apples and sometimes it's apples to elephant boogers. Setting aside the relative quality that you might expect from one manufacturer or another, the VA only equals W if the load is purely resistive. Once the load becomes reactive (not to be confused with radioactive), then you get into power factor correction. Depending on how far off the current and voltage peaks are from one another, you can get wildly differing numbers.
Grey
Have any recommendations for choosing a transformer then?
I was also looking at the Parts Express transformers. Is the 225VA enough for an F4? The next step up is 330VA. They don't have 18-0-18 in that size, but I could get 35-0-35 and wire the primaries in series.
I was also looking at the Parts Express transformers. Is the 225VA enough for an F4? The next step up is 330VA. They don't have 18-0-18 in that size, but I could get 35-0-35 and wire the primaries in series.
ANTEK
I use these puppies from ANTEK 18v+18v @ 400VA.
No problems with them. I think Nelson tested a members at one point and found them acceptable. They are fairly inexpesive.
http://cgi.ebay.com/18-18V-400VA-To...Electronic_Components?_trksid=p3286.m20.l1116
I use these puppies from ANTEK 18v+18v @ 400VA.
No problems with them. I think Nelson tested a members at one point and found them acceptable. They are fairly inexpesive.
http://cgi.ebay.com/18-18V-400VA-To...Electronic_Components?_trksid=p3286.m20.l1116
This is the best audio forum. Thank you so much for the guidance. I wish I could buy you all a beer. 
-David
-David
Re: ANTEK
Oh heck!!! I just remembered I have 2 of these same ANTEK 18-0-18 transformers new in the box in my garage after changing my mind on a prior A30 build.
That saves me $94 from Parts Express for the Avel's. ANTEK's work very well. I have a 650VA Antek in my current A30 with excellent results.
Thanks mithomas for the memory jog.
-David
mithomas said:
Oh heck!!! I just remembered I have 2 of these same ANTEK 18-0-18 transformers new in the box in my garage after changing my mind on a prior A30 build.
That saves me $94 from Parts Express for the Avel's. ANTEK's work very well. I have a 650VA Antek in my current A30 with excellent results.
Thanks mithomas for the memory jog.
-David
I am running those same Anteks in mine, they somtimes buzz (physicaly) when my fridge is running other than that they work fine. There has been some discusson as to thier quality, having tried Avel, Plitron, Antek - Plitron was clearly the superior however at roughly twice the price I can put up with little hum. Evan Nelson rejects some Plitrons due to noise. Sadly as many amps as I build cost is a big factor and I hunt for bargins and live with the short comings. Apex does offer some bargins and they are not always posted on the web site. I always give Steve a call and check- He will be getting in some 1KV - 55v toroids in Dec at $30 bucks a heck of a deal.
my 2 cents
Bill
my 2 cents
Bill
wirewiggler said:
Hi Bill,
I had a similar experience with my Antek. The thing is absolutely silent, except when my front porch is turned on, then there's a slight buzz coming from the transformer.
The Avel Lindberg Y23 model in my BOSOZ preamp is perfect under all conditions.
How funny.
-David
I used and loved the 300VA Plitrons too until I was told by their sales manager they require a $250 minimum order now. Time to try one of those 400VA Anteks...
Not sure if this helps but OPC has a few transformers for sale over on the trading post.
I picked one up for an F5
I picked one up for an F5
tms0425 said:
I would absolutely buy an Avel over the Antek.
The Avel 250va 18-0-18 from Parts Express for $50, no tax and free shipping special under way.
The Antek's are good and the eBay who sells them is first rate to deal with. Owning both, the Avel is much better made.
Just my $.02 worth,
-David
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