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Old 14th February 2009, 10:34 PM   #11
chrish is offline chrish  Australia
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The Hammond 193H (5H 200mA) is ample for this project. It is much cheaper (and lighter/smaller) than the 193J I am using the 193H and have zero hum.

Don't use FREDs. These have caused problems for many builders. Just use a valve rectifier. As the Hammond transformers put out more that their rated voltage, the voltage drop of the valve rectifier is useful, as is the slow power-up.

High end parts are not required, just be smart about what type of part you use. Going with the parts as recommended by Tubelab is a very good place to start - he knows his stuff! Good source of reasonably priced coupling caps is Soviet stuff on eBay.

Money saved on not over-specifying resistors/choke etc can be spent where it will actually make a difference: the output transformers.

To be honest, mid-range clarity is more important than bass to me. I have found in my system that EL34s sounded better than the twice as expensive KT88s. It is fun to swap power valves though, and if you do this I would suggest a switch to be able to vary the cathode bias resistance.

Cheers,

Chris
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Old 14th February 2009, 10:59 PM   #12
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Quote:
Originally posted by chrish
The Hammond 193H (5H 200mA) is ample for this project. It is much cheaper (and lighter/smaller) than the 193J I am using the 193H and have zero hum.

Don't use FREDs. These have caused problems for many builders. Just use a valve rectifier. As the Hammond transformers put out more that their rated voltage, the voltage drop of the valve rectifier is useful, as is the slow power-up.

High end parts are not required, just be smart about what type of part you use. Going with the parts as recommended by Tubelab is a very good place to start - he knows his stuff! Good source of reasonably priced coupling caps is Soviet stuff on eBay.

Money saved on not over-specifying resistors/choke etc can be spent where it will actually make a difference: the output transformers.

To be honest, mid-range clarity is more important than bass to me. I have found in my system that EL34s sounded better than the twice as expensive KT88s. It is fun to swap power valves though, and if you do this I would suggest a switch to be able to vary the cathode bias resistance.

Cheers,

Chris


Thanks for the reply.


I will take a look at the other hammond..


What is a valve rectifier? And does it go in the same place as the FREDS?



I might also take your advice with the resistors and such. The Amp is already beginning to get pricey. I think the Power Transformer and choke where about a $175 at AES. And I am assuming the OPT's are going to be around a $100+ for the pair. I don't know the exact price on them yet. I'm still waiting for an email back..


I've decided to slow down just a little and wait for some emails to come back. And also wait to here from George before I get to deep. Somebody said he is at show this weekend. So hopefully I will here from him this coming week.




Nick
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Old 14th February 2009, 11:26 PM   #13
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Ok. I've been doing some reading and I think I am VERY VERY slowly figuring out some of this stuff.


First off. The FREDS. and Valve Rectifiers.

The rectifier is the 5AR4 tube correct?

I can run the Rectifier tube without the FREDS installed correct?

With the FREDS installed I can run the amp without the tube but it will be SS. Correct?

A valve rectifier would go in place of the tube and make it SS correct? If so I don't want this. I want all of the tubes to work and no SS action at all.




I hope you guys can bare with me. I am more of a hands on type of guy. But if read something enough. (IE over and over) It starts to click eventually. Or at least a little maybe.





Nick
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Old 15th February 2009, 01:53 AM   #14
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I think Chris is still using the King's good english. They call vacuum tubes "valves". It's all the same. You are correct, the 5AR4 is the rectifier tube (or rectifier valve, as Chris calls it).

If you're looking to save money on the power transformer and filter choke, consider the 6K7VG and C-14X from Allied Electronics.
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Old 15th February 2009, 02:15 AM   #15
Jeb-D. is offline Jeb-D.  United States
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The CEO, President, Senior VP and janitor of tubelab.com (just kidding, it's a one man company)
Your forgetting the accountant (his wife). It's really a 2 person company

Nick,
Don't worry. George (tubelab) is an honest guy, but very busy. You will get your boards. KT88 or 6550 amp would be sweet.

That Jolida amp is nice looking. What are those, 6L6?
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Old 15th February 2009, 03:50 AM   #16
chrish is offline chrish  Australia
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Sorry for the confusion. Yes "valve" is the English expression for thermionic valve, known to Americans as "vacuum tubes". They are the same thing. The term is (almost) interchangeable. If you want to know which term is more correct, have a look at the schematic diagrams. You will see these devices listed as "V1, V2" etc, not "T1, T2".

This post is, of course, meant to be very tongue-in-cheek
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Old 15th February 2009, 03:54 AM   #17
pchw is offline pchw  United States
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Originally posted by nikolas812
And I am assuming the OPT's are going to be around a $100+ for the pair. I don't know the exact price on them yet. I'm still waiting for an email back..

Nick
Hey Nick,

Here is the OPT
http://cgi.ebay.com/ws/eBayISAPI.dll...m=280312784350

$127.35 shipped :-)
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Old 15th February 2009, 03:56 AM   #18
chrish is offline chrish  Australia
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Regarding the FREDs, they have caused problems for me. This happened at the same time I had problems with the standby switch. I suspect a voltage spike from turning the standby switch on fried my FREDs, which then in turn fried my GZ34 rectifier valve (tube). Have gone through two sets of FREDs. Removing them and the standby switch and using a new rectifier valve (now a Sovtek 5AR4 and occasionally a 5U4GB) has resulted in zero problems.

As for output transformers, I think there has been much discussion.

Cheers,

Chris
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Old 15th February 2009, 04:49 AM   #19
chrish is offline chrish  Australia
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Those Transcendars are supposed to be quite good. They do not, however, have an ultralinear tap. You will be restricted to triode mode only. For what it is worth, I run my Simple SE in triode mode about 95% of the time... If your speakers are reasonably efficient triode should be OK.
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Old 15th February 2009, 11:36 AM   #20
DimZ is offline DimZ  Greece
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i have the bigger transcendars with ultralinear tap (5K/15w/50% ul tap) with taps for both 8 and 4 ohms, you can email gery and ask him

i paid for mine something like 150 - 160 $ about 2 months ago


i use also the hammond 374bx and the hammond 193J choke and the cap from ebay, alps blue beauty 100k and everything else is exactly as George's parts list
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