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Questions about how it's built (Read 1970 times)
If the 1st watt
sucks why continue?
Questions about how it's built
02/08/11 at 17:46:37
Dear Mr Deckert,
I currently own an upgraded separo se88i amplifier (8-10wpc). I have posted some images and questions on a forum as my amp is clipping at just over half volume. On complex music or heavy metal the sound seems to loose timing/composition and the treble becomes harsh. I only very occasionally listen to heavy metal. If I listen to an old cd which seems to have less "gain" on the recording I can push my amp to 2/3 -3/4, but a modern loud recorded cd can generally only be pushed to just over 1/2 volume. My speakers are klipsch RB61 95dB sensitivity. The responses have been that my amp has way too much gain, loads of negative feedback, the pre amp stage is a phono stage stuck onto the out put tubes and that it is better for me to make my own amp. That I should try 2A3 or 300B opinion seems to vary as to what the person owns who is giving the advice. I can read a schematic with a little help form google now and again but the "how to" actually know which pins to solder to what is missing. Yep I can replace caps and resistors on a dead circuit but scoping and testing a live circuit is not for the untrained. I don't like hospitals much!
I have been looking around for a SET amp with no negative feedback. MEG audio made a nice couple of amps but they seem to have vanished (lack of email response). I have two pair of GE JAN 6550a tubes and a load of 12ax7, 12au7 and all the variants of this type other than medical grade tubes. I think I would like to stick to an amp that uses kt88 or 6550a tubes as I currently have them. NOS 300b tubes are very expensive and even a matched pair of modern ones is more than the price of a pair of NOS GE6550 tubes.
I like the look of your zen triode integrated 6 wpc amplifier. It looks well made, has a certain charm and people think it sounds good/hi-end. I have looked at so many "hi end" amps that seem to be part pcb, made with the odd exotic cap with a load or rubycons, the same amp with varying makes/logos and the associated price. The list goes on. But to put it bluntly. What one pays and what one gets seems to not go hand in hand. I have a few questions some of which probably very much point to the fact that I am not very knowledgeable.
Do you use an ALPS volume pot in this amp?
The stock volume control in the amp is an alpha, with the option of going to a stepped attenuator (Goldpoint MiniV)
Are the control knobs solid metal?
Depends on which ones you want. We can use either gold plated solid brass knobs, or vintage chickenhead knobs (plastic with steel insert). Price remains the same.
You say you use one capacitor in the signal path, what make is this cap please and could/would you swap it to a mundorf silver foil in oil or nichicon muse cap if i was to place an order with you? I used these caps in my current amp. The mundorf really makes the sound layered and improved the sense of 3D. The nichicon improved the sound allot as well.
The coupling cap is an FKP-1 series polypropylene film and foil that we had made to our specs by Wima in Germany. They're real good. I can custom build the amp with VCAPS or Mundorf as well.
Can you make the amp to UK 240v? We are not 230v as some people in the UK seem to think. The powers that be just fudged the figures so it looks like we are the same as the rest of Europe.
The amp will be configured for 240 volts, but will work with 230 ~ 250 volts without issues.
If I wanted to use KT88 or 6550 tubes would they just drop in or would there need to be adjustments made?
The SE34I.2 was only compatible with EL34 or KT77. Tubes with a metal base, like the 6550 would have high voltage on the metal base. Since the CCE mod last year, all SE34I.2 amps no longer have this restriction. The CCE mod takes the sound of an EL34 to a place no 6550 or KT88 or KT77 can go. You can still use these tubes, but the CCE mod will have no effect with them.
The toggle switch that changes the sound, is this like adding increasing degrees of negative feedback?
There is no negative feedback in the amplifier. The toggle switch controls a bypass cap on the cathode resistor of the output tubes.
The 34 tubes are quite thin compared to some kt88 tubes, is there enough space between a kt88 and the rectifier tubes? Have you tried lots of different makes?
Yes and yes.
Is the power transformer in the chassis and is it toroidal?
The amplifier is dual mono with both power transformers on the top of the amp. We make all our own transformers, power and output, one of the secrets to our success.
I am interested to see the quality of the internal wring, can you possibly email me an image?
Sorry to ask all this, but I want to make sure I am getting a good product that is as well made as it looks, worth the money and sounds great. Sadly you are a few thousand miles from me so I cannot just pop round to have a listen and a look.
Agreed. We overbuild our amplifiers. Less than 1% failure rate over 15 years. Lifetime warranty.
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Re: Questions about how it's built
Reply #1 -
02/08/11 at 20:26:29
I can't read your replies on the light blue background.
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