Output Transformer Secondary Impedance for Forte 1

[Mark51]

I'm about to upgrade the output transformers on a couple of single ended amps I have built.  One is a 6V6 and the other is an el84 both triode strapped.  Both are using budget Edcor transformers with an 8 ohm secondary only.  The input terminals on the Forte's say 4 ohm but the original Klipsch spec sheet says the nominal impedance is 8 ohms.  Some guy on another forum says that's because many solid state amps only had an 8 ohm tap.  Before I buy a pair of more expensive output transformers I'd like to know I've selected the best sounding secondary impedance.  Does anyone have any experience with the Forte 1 in this regard?  Perhaps the only way to know is to purchase transformers with multiple output impedances but the only ones I know of I could possibly afford are the higher end Hammond transformers and I'm hoping not to spend that much money being an old retired guy.  I must say the Forte's  sound good on the current 8 ohm tap even with the cheapo output transformers.  

[henry4841]

I have been using the Hammond 125CSE, 125DSE and 125ESe in my more recent builds with total satisfaction. I bought some from this Ebay seller and they came directly from Mouser. https://www.ebay.com/itm/285222340580?hash=item42689387e4:g:vc0AAOSwW2JkLjpa&amdata=enc%3AAQAIAAAA4NXz2fZvcy54bK1PuIJZJAY5i%2Fdo8zcr21CMyaq9rePl2oNkyblrA4UWYHY3DsVRjgLygDiQVi3uzJ%2FUJgAJlIhoUjAxBCi0C8cr4BOUpY2cHPAarmWXWCxmhwR7V6%2BH49BrF8hC8AIefKWrxKU3pQpXCEDfc04YYAHuQQ30fQD17mZ4P5rmlaOthj69jgCdqqlUTMOMIcLeniIY6dy28EYpVt4vso9jsKcdIGIqqm84MX4iot8sk6CEa3pFUp1E0sI%2Fj%2FDRZv8ZtLQc9eiepfKoCPlHqCX5dtFAWGTY3qYV|tkp%3ABFBMru7_0tti

[DirtyErnie]

If you're running in Triode mode, the amplifier is a lot less sensitive to speaker impedance variation than a Pentode amp. 

That said, higher level Edcor stuff has a great reputation.  That said, if it sounds good enough as-is, why change?   

[OO1]

On 9/28/2023 at 3:09 PM, henry4841 said:

I have been using the Hammond 125CSE, 125DSE and 125ESe in my more recent builds with total satisfaction. I bought some from this Ebay seller and they came directly from Mouser. https://www.ebay.com/itm/285222340580?hash=item42689387e4:g:vc0AAOSwW2JkLjpa&amdata=enc%3AAQAIAAAA4NXz2fZvcy54bK1PuIJZJAY5i%2Fdo8zcr21CMyaq9rePl2oNkyblrA4UWYHY3DsVRjgLygDiQVi3uzJ%2FUJgAJlIhoUjAxBCi0C8cr4BOUpY2cHPAarmWXWCxmhwR7V6%2BH49BrF8hC8AIefKWrxKU3pQpXCEDfc04YYAHuQQ30fQD17mZ4P5rmlaOthj69jgCdqqlUTMOMIcLeniIY6dy28EYpVt4vso9jsKcdIGIqqm84MX4iot8sk6CEa3pFUp1E0sI%2Fj%2FDRZv8ZtLQc9eiepfKoCPlHqCX5dtFAWGTY3qYV|tkp%3ABFBMru7_0tti

looks to be a good choice

[henry4841]

Having used both Edcor and Hammonds transformers I would not say one is better than the other. They both build and sell great transformers. Hammond gets my nod now because I do not have the patience to wait a few weeks for Edcor to build them. The drawback is to look nice, IMHO, the Hammonds need to be placed underneath the chassis. That being said many do not and I personally have no problem with them being placed on top. 

[tube fanatic]

As was stated above by DE, speaker impedance is not an issue for SETs.  If you use an opt tap corresponding to the lowest impedance of the speaker, distortion will decrease as the impedance rises.  I believe Edcor’s bandwidth ratings are at 1 watt whereas Hammond’s are at full rated power.  If used well below that, the Hammonds are capable of amazing bandwidth.  See George Anderson’s measurement of the 125CSE:

 

http://tubelab.com/articles/component-testing/budget-output-transformers/

 

Maynard

[NOSValves]

I don't think I'd describe either Edcor or Hammond as great output transformers...  Good for the $ yes, but far from great! Great cost a lot more than that!