Author Topic: How to Build a killer Amp  (Read 44249 times)

Offline omodo

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Re: How to Build a killer Amp
« Reply #40 on: January 30, 2011, 10:38:33 AM »
Lundahl OPTs ?


Offline Jehuty

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Re: How to Build a killer Amp
« Reply #41 on: July 05, 2011, 06:57:17 PM »
Steve, I found these NOS UTC output transformers on eBay, could you tell us if we can use these for the killer amp?

http://www.ebay.com.au/itm/UTC-S-16-output-transformer-matching-pair-NOS-tested-/180690089283?pt=Vintage_Electronics_R2&hash=item2a11f7f543
Item number: 180690089283
BIN: USD 599
Shipping to Australia: USD 43.23
Additional info: Date/run number is GV21. The primary specs are as follows: 3000 ohm for 45/2a3/6a3/6a5/6b4, 6000ohm for 2a5/6f6/6as7/46/6a6/6n7, 9000/10000 ohm 45/2a5/6ac5/6b5/6f6/6l6/6v6/807. The secondary is as follows 8 ohm/15 ohm and 500 ohm. Impedance and tube type data as published in radio master catalog.
Some pics attached.

I know it's pricey but hey this is a killer amp and if these UTCs sound a killer then I shall go for them!  8)

Cheers,
William
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Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #42 on: July 06, 2011, 04:34:35 PM »
Steve, I found these NOS UTC output transformers on eBay, could you tell us if we can use these for the killer amp?

http://www.ebay.com.au/itm/UTC-S-16-output-transformer-matching-pair-NOS-tested-/180690089283?pt=Vintage_Electronics_R2&hash=item2a11f7f543
Item number: 180690089283
BIN: USD 599
Shipping to Australia: USD 43.23
Additional info: Date/run number is GV21. The primary specs are as follows: 3000 ohm for 45/2a3/6a3/6a5/6b4, 6000ohm for 2a5/6f6/6as7/46/6a6/6n7, 9000/10000 ohm 45/2a5/6ac5/6b5/6f6/6l6/6v6/807. The secondary is as follows 8 ohm/15 ohm and 500 ohm. Impedance and tube type data as published in radio master catalog.
Some pics attached.

I know it's pricey but hey this is a killer amp and if these UTCs sound a killer then I shall go for them!  8)

Cheers,
William
William they are too pricey, but more importantly, sound wise unknown. Leave them there is better out there for the money.

Offline Jehuty

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Re: How to Build a killer Amp
« Reply #43 on: July 06, 2011, 05:04:44 PM »
Steve, I found these NOS UTC output transformers on eBay, could you tell us if we can use these for the killer amp?

http://www.ebay.com.au/itm/UTC-S-16-output-transformer-matching-pair-NOS-tested-/180690089283?pt=Vintage_Electronics_R2&hash=item2a11f7f543
Item number: 180690089283
BIN: USD 599
Shipping to Australia: USD 43.23
Additional info: Date/run number is GV21. The primary specs are as follows: 3000 ohm for 45/2a3/6a3/6a5/6b4, 6000ohm for 2a5/6f6/6as7/46/6a6/6n7, 9000/10000 ohm 45/2a5/6ac5/6b5/6f6/6l6/6v6/807. The secondary is as follows 8 ohm/15 ohm and 500 ohm. Impedance and tube type data as published in radio master catalog.
Some pics attached.

I know it's pricey but hey this is a killer amp and if these UTCs sound a killer then I shall go for them!  8)

Cheers,
William

William they are too pricey, but more importantly, sound wise unknown. Leave them there is better out there for the money.

Thanks Steve, you saved me lots of money there! Next time if these UTCs come up again and not that dear, I'll get them and let you play around with.  ;)
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Offline Jehuty

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Re: How to Build a killer Amp
« Reply #44 on: July 30, 2011, 10:37:35 PM »
To run choke imput, a nice choke for that, is 1/ UTC- CG 40  10H about 200 ma, 1950s. United transformer company, New York

Steven,

There's a Triad C-16A choke on eBay:
Item number: 370529262048
Spec: 10H, 200mA, 150 OHMS, 2500 volts
Link: http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=370529262048&ssPageName=STRK:MEWAX:IT

Is it good for input choke?

Cheers,
William
Not all that matters can be measured, not all that can be measured matters.

Offline Jehuty

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Re: How to Build a killer Amp
« Reply #45 on: July 31, 2011, 07:52:31 PM »
Just talked to Steven, it looks like it's got flying leads underneath which probably made of tinned copper which doesn't sound good so I'd better stay away  ;D
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Offline Jehuty

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Re: How to Build a killer Amp
« Reply #46 on: December 09, 2011, 03:08:38 AM »
Hi everyone,

I am building my dream amp with Steven's guidance at the moment and I need to get a pair of output transformers for the RCA UX-250 SET amp.

I've got a few options: Tamura F7001 or F7002, Hashimoto H-30-3.5S, Tango X3.5S - pre ISO Tango (doubt it because of the high price) and Tribute output transformers. I am currently leaning to Tribute because it's custom made and the price is very reasonable, so I need some advice about the most appropriate OPT spec to run the RCA UX-250.

I did send email to Pieter, see below:

Hello William,

Thanks for enquiring.

UX-250 is some 20 watts maximum plate dissipation, Rp 1k8, 50 mA DC.
I guess primary impedance 5k.
Basically two options: wound on HiB silicon steel c-cores, or amorphous alloy c-cores.
Price for a pair 325,- Euro (HiB), or 375,- Euro (amorphous).
These prices are without VAT (when you live inside the EEC, there is additional VAT of 19%).
Shipping not included.
Transformers are potted and finished, ready for chassis mounting.

Best regards,

Pieter Treurniet
Tribute Audio Transformers


What do you guys think? Is 5k impedance suitable? The Tamuras, Tango and Hashimoto are about 3 to 3.5k impedance and the Tamura F7001 did work on Steven's amp from what he told me. Is the primary max DC 50 mA good enough? And what is "Rp 1k8"? :-[

Cheers,
William
Not all that matters can be measured, not all that can be measured matters.

Offline Jehuty

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Re: How to Build a killer Amp
« Reply #47 on: January 07, 2012, 05:41:18 AM »
After quite a lenghty discussion with Pieter, I decided to put an order for a pair of his OPTs, spec: 2 SE output transformers HiB c-cores 3k5-5k/8-16R/100mA, potted 12x12cm, 6kg each, good enough to run 300B or PX25 if I need more watts.

It's a bit of gamble to order without listening but I hope the review on the net is not very wrong, otherwise Steven's Tamura F7001s will be gone before he knows it  ;D
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Offline zenelectro

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Re: How to Build a killer Amp
« Reply #48 on: January 07, 2012, 10:35:55 AM »
Jehuty,

These Tribute transformers look very nice.

The fact that he is conversant with a wide range of applications, for example stepped TVC toroid style, indicates a depth of knowledge and lateral approach.

I'm not sure about potting or varnishing OP transformers. Speak to Steven WRT this.

cheers

 

Offline Jehuty

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Re: How to Build a killer Amp
« Reply #49 on: January 08, 2012, 06:56:32 PM »
Thanks T, it's good to know that he's knowledgeable and from what I read on the net, his OPTs are up there with some of the best OPTs you can get. I have high expectation and I might try his chokes too if I like his OPTs  :)

Steve doesn't like potted OPT because the pot could potentially dampen the OPT too much and take away the life of music... I personally like it potted because it's neater and the Tamura F7001s (damn fine OPTs) I heard at Steven's were potted too...so personal choice plays a role here, hopefully I got this one right, now the long wait begins....
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Offline zenelectro

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Re: How to Build a killer Amp
« Reply #50 on: January 08, 2012, 09:57:19 PM »
Thanks T, it's good to know that he's knowledgeable and from what I read on the net, his OPTs are up there with some of the best OPTs you can get. I have high expectation and I might try his chokes too if I like his OPTs  :)

Steve doesn't like potted OPT because the pot could potentially dampen the OPT too much and take away the life of music... I personally like it potted because it's neater and the Tamura F7001s (damn fine OPTs) I heard at Steven's were potted too...so personal choice plays a role here, hopefully I got this one right, now the long wait begins....

I was actually thinking more of the resin and varnish having certain dielectric properties. However it is probably a combination of dielectrics + microphonics.

Less spectacular description, sorry. :)

Looking at a parallel audio field, I'm thinking guitar pickups here. 100's of thousands are made / sold yearly trying to re create / improve
vintage Fender / Gibson pickups and a huge of research has gone into it.

The findings: Dry winds are generally superior sound wise and also type of wire insulation. Apparently some of the older insulations are not available any more.

They do other tricky stuff that I'm not even going to talk about because it's also applicable to chokes / transformers.

Good luck with the transformers.


Offline springcreek

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Re: How to Build a killer Amp
« Reply #51 on: January 08, 2012, 10:27:55 PM »
Hi Jehuty

Have you thought about getting Dave Slaggle from Intact Audio http://www.intactaudio.com/tran.html in the states to make you a pair? Dave has an amazing reputation for winding great transformers for SETs and his favourite tube is...you guessed it the 50! He makes a high nickel content transformer that is supposed to be 'better' than amorphous. I have heard the description of the two described in terms of food, amorphous is like a really high quality meal from a great restaurant and high nickel content is like the soul food you always want to come home to.

I hope to build Steven's 50 amp in the future (when I can afford it and after I've done up the Fisher!). I think I will get Dave to make me some trannies for me.

Dave and amp builder Jeffery Jackson (who makes great 50 amps himself http://www.jeffreywjackson.com/amplifiers.htm) have a blog called hifi heroin http://www.hifiheroin.blogspot.com/.

Hope it's useful.

Cheers, Andy
 

Offline zenelectro

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Re: How to Build a killer Amp
« Reply #52 on: January 08, 2012, 10:49:40 PM »
Hi Jehuty

Have you thought about getting Dave Slaggle from Intact Audio http://www.intactaudio.com/tran.html in the states to make you a pair? Dave has an amazing reputation for winding great transformers for SETs and his favourite tube is...you guessed it the 50! He makes a high nickel content transformer that is supposed to be 'better' than amorphous. I have heard the description of the two described in terms of food, amorphous is like a really high quality meal from a great restaurant and high nickel content is like the soul food you always want to come home to.


Andy

Traditionally high nickel or similar are the best cores for low level (signal) but are difficult to use for audio outputs.

If Dave has managed to do it that's definitely worth checking out.

I suppose at 2 or 3 watts it's almost somewhere between signal and audio OP :)

T





Offline Jehuty

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Re: How to Build a killer Amp
« Reply #53 on: January 09, 2012, 12:12:40 AM »
Hi Jehuty

Have you thought about getting Dave Slaggle from Intact Audio http://www.intactaudio.com/tran.html in the states to make you a pair? Dave has an amazing reputation for winding great transformers for SETs and his favourite tube is...you guessed it the 50! He makes a high nickel content transformer that is supposed to be 'better' than amorphous. I have heard the description of the two described in terms of food, amorphous is like a really high quality meal from a great restaurant and high nickel content is like the soul food you always want to come home to.

I hope to build Steven's 50 amp in the future (when I can afford it and after I've done up the Fisher!). I think I will get Dave to make me some trannies for me.

Dave and amp builder Jeffery Jackson (who makes great 50 amps himself http://www.jeffreywjackson.com/amplifiers.htm) have a blog called hifi heroin http://www.hifiheroin.blogspot.com/.

Hope it's useful.

Cheers, Andy
  

I wish you had told me earlier about this Andy.....thanks for the info by the way, still very useful  :)

Oh well....I'll play around with the Tribute and if I'm not happy with them I'll just use them for my bass amp...Oh yeah I'm going to build another one in the future ;D

I'd like to hear what you think about the Intact OPT when you get them, apparently Audio Note UK uses nickel core too for their top of the line OPT... http://www.audionote.co.uk/articles/art_transformer_design.shtml and http://www.audionote.co.uk/comp/trans/trans_01_tx_news.shtml

Cheers,
William
« Last Edit: January 09, 2012, 12:23:12 AM by Jehuty »
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Offline Jehuty

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Re: How to Build a killer Amp
« Reply #54 on: January 09, 2012, 12:27:33 AM »
I was actually thinking more of the resin and varnish having certain dielectric properties. However it is probably a combination of dielectrics + microphonics.

Less spectacular description, sorry. :)

Looking at a parallel audio field, I'm thinking guitar pickups here. 100's of thousands are made / sold yearly trying to re create / improve
vintage Fender / Gibson pickups and a huge of research has gone into it.

The findings: Dry winds are generally superior sound wise and also type of wire insulation. Apparently some of the older insulations are not available any more.

They do other tricky stuff that I'm not even going to talk about because it's also applicable to chokes / transformers.

Good luck with the transformers.



Thanks T, any information you share is always appreciated.

Interesting you mentioned that some older insulations are better, that may be one of the factors Steve likes the silk insulated Hanley wires, you know he calls it the holy wire  ;D

Cheers,
William
Not all that matters can be measured, not all that can be measured matters.

Offline springcreek

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Re: How to Build a killer Amp
« Reply #55 on: January 09, 2012, 10:03:26 PM »
Terry and William

Dave seems to have it well sorted and is now making 80% nickel transformers, chokes and autoformers. Jeff Jackson thinks of all the stuff he has tried, the high nickel presevers the low signals best as Terry says. Jeff uses lots of this stuff in his amps plus mercury rectifiers and a lot of chokes and PIO caps to filter the supplies. Very cool and very heavy amps. Given these guys are horn nuts they make there stuff quiet and dynamic. Would love to hear such a system! :o

I asked Dave to give me an idea on price for some of his kit. Will let you know.

Still loving the Fisher with the Goodmans Triaxioms. Will be interesting to see how far I can take the Fisher. Ordered some Russion PIO K40y caps the other day so I'll see how they sound. I had to order a dozen so let me know if anyone wants some to try them and I'll send some through, though they are only small values 0.047uF 630V. Should be ordering some new 2W Allen Bradleys in the coming week.
And my lovely wife is going to get me a new soldering station for my birthday  ;D

William good luck with the Tribute trannies, let us know how they go. ;)

Cheers, Andy

Offline zenelectro

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Re: How to Build a killer Amp
« Reply #56 on: January 10, 2012, 01:17:01 AM »
Terry and William


And my lovely wife is going to get me a new soldering station for my birthday  ;D

Cheers, Andy

It's hard to believe but these are actually pretty good.

http://www.ebay.com.au/itm/60W-Soldering-Iron-Station-Digital-Temperature-Control-/200690433764?pt=LH_DefaultDomain_15&hash=item2eba14fee4

I got about 18 months out of one and it works all day every day = probably 12 hrs on. I've trashed $300 units in 6 months.

T


Offline springcreek

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Re: How to Build a killer Amp
« Reply #57 on: January 10, 2012, 07:38:07 AM »
Thanks Terry

I will check it out.

I was thinking of getting one of these http://www.rhinotools.com.au/soldering-station/124-soldering-station-digital-48w.html

Cheers, Andy

Offline gamve

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Re: How to Build a killer Amp
« Reply #58 on: January 10, 2012, 11:46:03 AM »
Guys, I brought a Rhino Tools de-soldering station a while back. Only used it a couple of times so far
but it works really well. Looks are similar to the link like terrys. They also do a dual unit with a both.

Offline ozcal

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Re: How to Build a killer Amp
« Reply #59 on: January 10, 2012, 12:49:20 PM »
Guys, I brought a Rhino Tools de-soldering station a while back. Only used it a couple of times so far
but it works really well. Looks are similar to the link like terrys. They also do a dual unit with a both.
Thanks for the heads up GM , will grab one when I have the cash.
Listening with my ears :)