[wallijonn]

Joelongwood,

aren't you the gentleman who is replacing all the wiring up to, and perhaps including all the wiring inside, the k1000?

I've always been fascinated by/in teaming a carver amp with the k1000s. I would think that it/they would sound superb. The magnetic field power is basically a torrorial (spell?) transformer with special circuitry to supply almost unlimited transient headroom at any frequency. I always called it the "hugger" wave (you'd would have had to had read their literature when they were first produced, to understand).

class a: http://www.gmweb.btinternet.co.uk/sugden10w.htm
class ab: http://www.gmweb.btinternet.co.uk/jlhab2.htm

I've always wanted to see what the schematic looks like for the carver amp.

KW, the Crown D60 is all I want to afford, for now. I'm hoping it's a good model, as it was constructed immediately after the Crown plant burned to the ground. I'm hoping that they couldn't afford to make a lousey product.

Anyone have a complete list of all class A amps ever made?

Greg Freeman's SAC was wired correctly.

Why did you dismiss the carver amp? do you know something i don't know? please "edumacate" me as I have always had a fascination with them. I know that there are/were quality control issues with many of their products, but I have always heard that they were beyond reproach in listening tests.

wouldn't the nOrh put out about 500mw at 120 ohms? or would you use the 4 ohm tap (are there more than one?) to get 1000mw?

 

[mikeg]

Quote:

Originally posted by msjjr I have the ETY 4S and it is not more revealing than my modified AKG 1000. Maybe I should get the Omegas as well.

I agree. I also have the ETY 4P with cable converter to 4S. Although I use it when in a library, or other places where I don't want to bother others with my music, in my opinion its not comparable to the K1000. Compared to the K1000, the ETY 4S lacks a broad sound stage, richness of sound, and rich detailed base, when compared to the K1000. The 4S is good, but not in the same league as the K1000.

 

[mikeg]

Quote:

Originally posted by joelongwood Question: I think I'm getting over the "ugly" factor of the K1000s. Enough so, that they are most likely in my future. I would rather not buy another piece of equipment to drive them, so I would like to use something I already have. Here are my choices- 1. Carver 6250 Receiver with Magnetic Field Power Amplifier technology.....whatever the hell that means. 2. Yamaha CA-1010 integrated amp (1977). According to Yamaha, it can be switched to run in Class A.......again, whatever the hell that means. 3. Dynaco PAS3X/Stereo 70 combo (large and bulky and HOT) I know it's just about impossible to find out how the AKGs will sound, but I'm curious as to what you guys think might be the most promising of the three choices. Thanks.

I'm glad to see that you're considering the K1000. You'll love it, but the problem is that, once you have it, you'll seldom use your other headphones. If it would help you, I could connect my K1000 to a Sony GX909ES solid state receiver, and let you know how it performs. I think that I briefly used it with this receiver several months ago, and it sounded fine.

 

[mikeg]

Quote:

Originally posted by Hirsch joelongwood, yeah, I'm definitely crazy. I've been trying to find the diagnosis in DSM-IV, but they don't have tubes listed in the index...

Look for someone who develops therapies for tube addiction. Got the idea from your profile.

 

[Gariver]

You guys are searching for K-1000 amps without taking into consideration the most important criteria: Output Impedance (Zo).

Peter Millett, the designer of Wheatfield Amps, designed and built an amp for his AKG K-1000s (linked below). He says that for the K1000s to sound full, the amp that powers it must have a low output impedance, Otherwise, the K1000s will sound thin. Meaning? They will lack bass.

Usually, tube amps have an output impedance of between 30 and 50. This is too high for the K1000s. So Mr Millett made his amp using an SRPP circuit. This type of circuit gives him: Improved linearity, high voltage swing and a very low output impedance of 7 Ohms. Results? He gets a full sounding amp with the necessary bass.

SRPP means Series Regulated Push Pull. Thus, if you are searching for a tube amp for your K1000s, I would go for a push-pull amp over SET amps (single ended triode). The push pull type of circuit insures the very necessary low output impedance. I believe those old Fisher receivers are push-pull. So they work very well with the K1000s.

Mr Millett explains SRPP in this quote...

"An SRPP amplifier uses two tubes wired in series - the lower tube's grid is driven, and it works like a normal grounded-cathode amplifier. The upper tube does two things; it acts like a constant-current source, which provides a constant plate current to the lower tube, hence a very high AC impedance, and a near-horizontal load line. When the load is taken from the cathode of the upper tube, it also acts as a cathode follower, providing a very low source impedance."

Solid state amps usually have a low output impedance. So most of them will work very well with the K1000s. It is only with tube amps that you have to be very careful. However, with SS, you do need to have the necessary voltage (power) to move the K1000s.

What's the best type of amp for the K1000s? The K1000s have a slightly metallic tone to them. What can you do? Well, you can only get rid of this metallic tone with a tube amp, not with an SS amp. So I do prefer the K1000s with a Class A, push-pull tube amp with an SRPP circuit!

Read the link below, Mr Millett explains the K1000 problem very well.
http://www.pmillett.addr.com/ecc99_s...dphone_amp.htm

I have two Class A tube amps for the K1000s: Audio Valve RKV and the Norh SE9. The K1000s sound very good with both amps. With its powerful push pull circuit, the RKV has an extremely low output impedance, and it sounds fantastic with the K1000s. The RKV beats the SE9, but not by a wide margin. So if you are low on funds, the SE9 fits the bill for only $399 (including shipping to the USA). I mean, the SE9 sounds great also! However, if you can swing it, the RKV is the perfect match for the AKG K-1000s!

When my friends try the K1000s with the RKV, I always have fun looking at their shocked faces. The sound is so good that their jaws drop and their eyes open up wide. They can't believe the superb sound they are hearing. Ha!

Feliz Navidad!

 

[mikeg]

Gariver - Since I'm not technically knowledgeable in this area, I'd appreciate your comments regarding the adequacy of the following amps for driving the K1000: ASL AQ-1005DT, and ASL Wave monoblocks. Thanks.

 

[Orpheus]

the ASL 1005 is a SET amp. the Wave is not.

...but you reported that you heard no difference.

so, Gariver, how is this discrepanacy explained?--perhaps this output impedance doesn't make that big of a difference?

thanks.... i also sent that article to Joe Lau of ASL, hoping he would design something similar in the future.

 

[Hirsch]

Quote:

Originally posted by Gariver SRPP means Series Regulated Push Pull. Thus, if you are searching for a tube amp for your K1000s, I would go for a push-pull amp over SET amps (single ended triode). The push pull type of circuit insures the very necessary low output impedance. I believe those old Fisher receivers are push-pull. So they work very well with the K1000s.

The Fisher 400 is indeed push-pull. It's also got rather massive output transformers, due to its primary use as a speaker amp. Output taps are 4,8,and 16 ohms. The full output of the power amp section is shunted to the headphone jack through attenuating resistors. The 16 ohm tap gets the K-1000 very loud very fast, so much so that I use the 8 or 4 ohm taps, just to have some play in the volume control. Any sonic differences I hear between the taps are masked by the volume changes.

I just got a second Fisher. I had originally planned to use it for parts, but when I got it, I found it's actually in better shape than the one I'm using. So, I'm going to restore it, and use my current one as a backup. $150, and all of the driver tubes are Fisher branded and good. Five of the nine 12AX7's are good-testing Telefunken smooth plates. What's not to like? It's actually usable as is, but new capacitors will have the K-1000 singing.

 

[Gariver]

I bought the RKV and the SE9 because they are both Class A. With the fine sounding AKG K1000s, you can really get every single drop of music juice out of Class A! I mean, the huge amount of details in a Class A amp are captured perfectly by the K1000s. That's just great!

I have not heard the ASL amps you mention. However, I have read quite a bit about them, esp the technical details. So I will offer you my guarded opinion, which you may dismiss if you wish.

I believe the RKV is a bargain at $850 (including USA shipping) from Jan Meier in Germany. As soon as the German and US economies improve, the RKV's price will go back to its old price of $1,295. So I would pick the RKV over the higher priced ASL AQ-1005DT for the reasons I mentioned above. That's is: Class A, push-pull and superb sound with the K-1000s.

Now, I would pick the Class A Norh SE9 for $399 (including USA shipping) from Norh in Thailand over the ASL Wave Monoblocks. In this case, you do pay more for the Norh. However, I believe the Norh is worth it. It does sound very, very good with the K1000s, and it comes close to the RKV's magic for half the price.

In both comparisons, I'm going for the Class A amps! A CD has 15 billion pieces of information in it, and the best way to get all that information to your AKG K-1000s is with Class A amps. That's my humble opinion on the matter.

Oh, least I forget: For the RKV to reach its maximum sonic perfection, you need four high-quality, German made, NOS Telefunken PCL805 tubes. The Siemens PCL805s tubes are also great for the RKV. What about the stock tubes? The stock, Polish made, Polamp PCL805 tubes are good tubes, but they are not as good as the two German tubes by Telefunken and Siemens. They clip the HFs a little bit.

Tubes for the Norh SE9? I have NOT had time to do the necessary tube research. So I'm using the stock tubes. Stay tuned!

That's it, Mike! Good luck in your quest for sonic nirvana!

Buena Suerte y Feliz Navidad!

 

[Gariver]

Orpheus:

I am sorry if I made a mistake with the ASL Wave. I really thought it was a SET amp. Like I said above, I am not familiar with the ASL amps. So you can dismiss my opinion if you wish. I did, however, try to give you guys all that's on my mind regarding the questions asked.

In general, I am following Peter Millett's guidelines for powering the AKG K-1000s. He is one of America's finest tube amp designers. So it makes a lot of sense to listen to his suggestions.

These are the Millett guidelines I've adopted...
--SRPP push pull circuit.
--Low output impedance: 7 Ohms or below.

On my own, however, I'm picking the Class A amps. I like the wealth of information Class A offers. This, of course, comes from having read a lot about Class A amps in the past. They are only 20 to 30% efficient. However, they do sound goooood!

Remember this: It's hard for me to check out tube amps here in Puerto Rico. Only a few audio shops her carry tube amps. So unlike you guys, I've got some serious audio limitations. Therefore, I do my research by reading a lot.

Can a tube amp that is NOT push-pull do justice to the K1000's very high sonic capabilities? Sure! The people over at Head Room Corp love to listen to the ASL AQ-1005DTI amp with the K1000s. However, with my audio limitations, I have to listen to Mr Millett with acute attention. I must do that! Otherwise, I'll make all sorts of costly mistakes. He is my tube amp GURU!

Talk about spending $$$...
Hirsch has the best solution! Buy a Fisher 400 for very little money, and you get a great amp for the K1000s. Congratulations, Hirsch! A Fisher for $150 with Telefunken tubes is really an audio bargain! It's really the audio bargain of the century. So you amaze me! He, he! Clever...very, very clever! I might follow you on that one! Maybe I can get Jude to name you as Head-Fi's Tube Amp Buyer of the Year!

Mr Peter Millett's K-1000 Amp...
Maybe we could get a group of K1000 users together to make a PCB of that amp. Anybody game for this feat? Mr Millett's low voltage, hybrid amp has a PCB for it. DIYcable.com sells it for $40.00 USD at their site. So a K1000 Amp PCB is indeed possible. Maybe Mr Millett will help us in this quest.

Buena suerte a todos!

 

[Joe Lau]

AV-8 and AQ1005 DT is design in difference topologies and have fifference type of sound.

AQ1005 DT - More detail , better mid range due to it is SET , Zero feed back.

AV-8 - Push/Pull design - More Dynamic and more extend High but it is get by more over all feed back , So it mid range can not compare with AQ1005 DT. AV-8 have high over all feed back and it benifite on lower output impedance and better damping. It may be good for AKG1000.


Rem : You should use 4 Ohm Tap on AQ1005 DT to drive AKG1000. It will get better performance.


It is hard to sell AV-8 in low cost due to parts cost increase in the past. EI 6BM8/ECL82 price increase to double due to it stock is not much now. May be We use too much EI tube in the past.

 

[wallijonn]

interesting article: http://sound.westhost.com/impedanc.htm

read the part about the cables (gasoline on the fire).

 

[msjjr]

That is utter nonsense. I hear a very obvious difference between the Senn HD600 with the Equinox vs Cardas cable; and I can A-B them directly because I have 2 sets of the 600's. I've already posted that I was able to consistently prefer the sound of what turned out to be the same cable 6/6 times in a single-blinded test using the AKG 1000. The issue as to which sound was better is entirely subjective, but the differences were objective and obvious. Anyone who has switched from the stock ETY cable to the upgrade "fixup" cable know exactly what I mean when I refer to the dramatic reduction in microphonics. Cables make a difference. The trick is to find those moderately priced gems that perform as well or, indeed, outperform the super sxpensive stuff.

 

[Orpheus]

gariver,

oh no... i didn't mean it that way. quite the contrary actually. i wanted to hear your opinion, cause i just dumped a bunch of money on a custom 300b SET amp. and if a $400 norh is gonna beat that amp (which is MUCH more expensive)... i should cancel that project immediately.

the Millet site says that symptoms of high output impedance include thin sound and lack of bass. i was wondering if you actually witnessed such deficiencies?

but i am talking with the rep for that amp right now, and he already spoke to his engineers to bias this 300b SET amp towards a impedance of 120 ohms for my k1000.... but i don't think he understood what "Zo" actually means. ...anyway, i sent him the Millet article, and hopefully he will understand after that. anyway, if this custom 300b SET amp is good, i'll post my experiences later. gonna take about 1 month to make though.

...sorry if you misunderstood. i value everyone's opinions on this site.... even the meannies.

orpheus

 

[msjjr]

Orpheus: I also have a 300B SET amp that has been biased to the AKG 1000's and the difference is amazing. That biasing adjustment has to be considered mandatory for any amp driving the 1000's.