Transformers to try.

TheGimp · 20th November 2009, 02:13 AM

I've got a set of Hammond 1609s, and a set of Olsons from the 70s along with a few strays that I'm playing with for my 6P1P PP amp.

It looks like the best fit from EDCOR is the CXPP25-MS-8K which is a 25W transformer. P-P impedance is below 10K (Ideal for 6P1P-EV for output power) and will result in less power, but should also result in lower THD if I understand O.H. Schade.

Also the larger transformer will keep me in the more linear portion of the BH curve since I'm only running 10W. I could also go with CXPP25-8-5K and use the 4 ohm output with an 8 ohm speaker to get 10K P-P loading, and could try Parallel Push Pull with the 8 Ohm tap and get around 20W out for four tubes. Or am I off the mark?

Does anyone have another suggestions while I'm playing with iron?

Plitron looks like they are higher power.

I'm selling all my home brewing equipment so now is the time to make investments in tubes and iron.

Sven

aardvarkash10 · 20th November 2009, 04:49 AM

Whatttttt!!!!!

How will you ever enjoy your diy hifi gear if you are not a little chemically altered first???

Mosquito · 20th November 2009, 04:32 PM

Iron & Glass are the matter that dreams are made of...
Cheers
JJ

TerryO · 20th November 2009, 05:53 PM

Quote:

Originally Posted by TheGimp

I've got a set of Hammond 1609s, and a set of Olsons from the 70s along with a few strays that I'm playing with for my 6P1P PP amp.

It looks like the best fit from EDCOR is the CXPP25-MS-8K which is a 25W transformer. P-P impedance is below 10K (Ideal for 6P1P-EV for output power) and will result in less power, but should also result in lower THD if I understand O.H. Schade.

Also the larger transformer will keep me in the more linear portion of the BH curve since I'm only running 10W. I could also go with CXPP25-8-5K and use the 4 ohm output with an 8 ohm speaker to get 10K P-P loading, and could try Parallel Push Pull with the 8 Ohm tap and get around 20W out for four tubes. Or am I off the mark?

Does anyone have another suggestions while I'm playing with iron?

Plitron looks like they are higher power.

I'm selling all my home brewing equipment so now is the time to make investments in tubes and iron.

Sven

Sven,
Are you trying to decide which transformer to use that you already own, or are you open to suggestions as to other transformers to try out? If this is the case, where are you located? The shipping costs can certainly be a factor when you're dealing with fairly heavy gear.

Best Regards,
TerryO

TheGimp · 20th November 2009, 08:20 PM

I live in Johnson City TN (USA).

I'm open to trying other transformers in addition to the ones I already have.

TerryO · 09:36 PM

Sven,
Here's a few that are highly regarded:
Magnaquest
Tango
Silk
Lundahl
James
Onetics

I'd probably look into the Onetic's line, if for no other reason than Bud Purvine (BudP) is on this forum and is readily accessible. Do a search on diyaudio and you'll be able to read several discussions that he took part in. The Onetics transformers are World Class and some of the top builders use his Iron.
(Disclaimer: I know Bud and we're on good terms, but my recommendation is not based on that factor.)

Best Regards,
TerryO

Kashmire · 21st November 2009, 02:47 AM

IMHO, Plitron is on top of the list. Expensive, but very good. The toroid configuration allows for very high magnetic efficiencies, and also has the benefit of containing the magnetic field. The specialist line is also very interesting (I have the cathode feedback model).

TheGimp · 03:24 AM

I'll have to check those out. I have limited resources (like most) but would like to try at least one more set of transformers.

The problem I have is I'm looking at 8-10W output and most transformer designers don't support this power level. I can use larger (20W-30W) transformers, but pay a premium for them.

I guess most amps are in the 20-30W range to support lower efficiency speakers.

Thanks.

planet10 · 21st November 2009, 03:21 AM

Quote:

Originally Posted by TerryO

Onetics

Got 3 sets of those... + a set in Chris' Wright Mono 7s. Nice.

Have been promised an amp with Plitron OPTs, looking forward to it too.

dave

Richard Ellis · 21st November 2009, 12:49 PM

Some more to consider...One-Electron, and SP Wound components Ltd.
I had a good talk with the fellows at SP wound, very helpful!
Jack at Electraprint is another good choice...more than willing to chat with.

________________________________________________Ri ck..........

20th November 2009, 02:13 AM	#1
TheGimp diyAudio Member Join Date: Aug 2009 Location: Johnson City, TN	Transformers to try. I've got a set of Hammond 1609s, and a set of Olsons from the 70s along with a few strays that I'm playing with for my 6P1P PP amp. It looks like the best fit from EDCOR is the CXPP25-MS-8K which is a 25W transformer. P-P impedance is below 10K (Ideal for 6P1P-EV for output power) and will result in less power, but should also result in lower THD if I understand O.H. Schade. Also the larger transformer will keep me in the more linear portion of the BH curve since I'm only running 10W. I could also go with CXPP25-8-5K and use the 4 ohm output with an 8 ohm speaker to get 10K P-P loading, and could try Parallel Push Pull with the 8 Ohm tap and get around 20W out for four tubes. Or am I off the mark? Does anyone have another suggestions while I'm playing with iron? Plitron looks like they are higher power. I'm selling all my home brewing equipment so now is the time to make investments in tubes and iron. Sven

20th November 2009, 04:49 AM	#2
aardvarkash10 diyAudio Member Join Date: Mar 2007 Location: Auckland, NZ	Whatttttt!!!!! How will you ever enjoy your diy hifi gear if you are not a little chemically altered first??? __________________ I don't know anything about music. In my line you don't have to. Elvis Presley (1935 - 1977)

20th November 2009, 09:33 PM	#6
TerryO diyAudio Member Join Date: Nov 2002 Location: Seattle,Wash.	Sven, Here's a few that are highly regarded: Magnaquest Tango Silk Lundahl James Onetics I'd probably look into the Onetic's line, if for no other reason than Bud Purvine (BudP) is on this forum and is readily accessible. Do a search on diyaudio and you'll be able to read several discussions that he took part in. The Onetics transformers are World Class and some of the top builders use his Iron. (Disclaimer: I know Bud and we're on good terms, but my recommendation is not based on that factor.) Best Regards, TerryO __________________ "If you have to ask why, then you're probably on the right track." quote from Terry Olson's DIYaudio Forum application Last edited by TerryO; 20th November 2009 at 09:36 PM. Reason: disclaimer added

21st November 2009, 03:19 AM	#8
TheGimp diyAudio Member Join Date: Aug 2009 Location: Johnson City, TN	I'll have to check those out. I have limited resources (like most) but would like to try at least one more set of transformers. The problem I have is I'm looking at 8-10W output and most transformer designers don't support this power level. I can use larger (20W-30W) transformers, but pay a premium for them. I guess most amps are in the 20-30W range to support lower efficiency speakers. Thanks. Last edited by TheGimp; 21st November 2009 at 03:24 AM.

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20th November 2009, 04:32 PM	#3
Mosquito diyAudio Member Join Date: Sep 2009 Location: Alto Verde	Iron & Glass are the matter that dreams are made of... Cheers JJ

20th November 2009, 08:20 PM	#5
TheGimp diyAudio Member Join Date: Aug 2009 Location: Johnson City, TN	I live in Johnson City TN (USA). I'm open to trying other transformers in addition to the ones I already have.

21st November 2009, 02:47 AM	#7
Kashmire diyAudio Member Join Date: Dec 2003 Location: Midwest	IMHO, Plitron is on top of the list. Expensive, but very good. The toroid configuration allows for very high magnetic efficiencies, and also has the benefit of containing the magnetic field. The specialist line is also very interesting (I have the cathode feedback model).

21st November 2009, 12:49 PM	#10
Richard Ellis diyAudio Member Join Date: Sep 2006 Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.	Some more to consider...One-Electron, and SP Wound components Ltd. I had a good talk with the fellows at SP wound, very helpful! Jack at Electraprint is another good choice...more than willing to chat with. ________________________________________________Ri ck..........

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