Best Amp & cables for Fostex FE206En BLH

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#23
bridger2086 said:
Upper-midrange also seems to be slightly subdued (perhaps related to bass increase)

The frequency anomaly in the lower-midrange persists however, making some male vocals sound a bit throathy/thin at times. Also noticeable with lower saxophone notes. That, as far as i've understood could be due to impropper damping of the cabinets? (Yes its 21mm plywood all round).

As for the amp, thanks for the suggestions. I guess the ACA and Triodes are the way to go. But will the bass still be there with a weak SET amp? 2-3w? I rarely play loud as the room acoustics don't allow it, but I would like the amp to keep up with peaks in a classical piece.

So no love for tripaths here? Are they gone and done?
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Likely IME.

'Sounds' like a horn and/or room dip IME, so could be.

Not familiar with the ACA, tri-path, but again, the pioneer's amp designs will track impedance whereas just outboard series resistance causes broadband shelving, i.e. trading efficiency for a wider/flatter in room BW, so the (mid) bass response tracks the horn's gain BW, which usually means more real gain in acoustic efficiency where we need it most = less electrical power required for a given SPL.

'Fast' transients requires having sufficient voltage, so while 2-3 W is fine for listening average wide BW SPL, transients on some recordings, especially classical can be up to +30 dB (clipped) = 10^(30/10) = 1 kW! minus the speaker's efficiency, so not surprisingly, low power amps clip like crazy and its 'quality' in doing so somewhat sets an amp's 'tone' with SS typically 'sharp' (or worse to the point of !@#$%^&) and tubes some 'flavor' of 'smooth to down right syrupy'.

Nowadays you again would want the pioneer's choice during the transition between the tube/SS crossover era to ~ 'have your cake and eat it too' = transformer coupled Class A or A/B with enough Class A power to handle at least your peak average SPL requirements with the standard 10 W being plenty for a HE BLH system and you can work out the amp's total power rating for transients based on your in room average, etc..
 
#24
planet10 said:
A high outpit impedance amplifier with your Belden should give simialr affect as the skinny wire.

dave
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Can you name some options, aside from SET amps and ACA? GM refered to, what i think are 70s Pioneer transistor amps that have high enough bias to work in cl.A most of the time? Im looking for "realistic" solutions. Something that is reasonably common or available, and preferably doesnt require a full overhaul and or building from scratch.

In other words, are there any other "groups/classes" of amps that work well with this type of driver/blh?
 
#26
GM said:
Likely IME.

'Sounds' like a horn and/or room dip IME, so could be.

Not familiar with the ACA, tri-path, but again, the pioneer's amp designs will track impedance whereas just outboard series resistance causes broadband shelving, i.e. trading efficiency for a wider/flatter in room BW, so the (mid) bass response tracks the horn's gain BW, which usually means more real gain in acoustic efficiency where we need it most = less electrical power required for a given SPL.

'Fast' transients requires having sufficient voltage, so while 2-3 W is fine for listening average wide BW SPL, transients on some recordings, especially classical can be up to +30 dB (clipped) = 10^(30/10) = 1 kW! minus the speaker's efficiency, so not surprisingly, low power amps clip like crazy and its 'quality' in doing so somewhat sets an amp's 'tone' with SS typically 'sharp' (or worse to the point of !@#$%^&) and tubes some 'flavor' of 'smooth to down right syrupy'.

Nowadays you again would want the pioneer's choice during the transition between the tube/SS crossover era to ~ 'have your cake and eat it too' = transformer coupled Class A or A/B with enough Class A power to handle at least your peak average SPL requirements with the standard 10 W being plenty for a HE BLH system and you can work out the amp's total power rating for transients based on your in room average, etc..
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Thanks, but what are you refering to with IME and BW? If i understand correctly, simply adding a resistor (or this really thin wire which i have installed now) will cause LF shelving, which is supposedly worse than "tracking" speakers impendance? Here is the FR and IR plot from fostex doc. Fairly flat IR with very high peak at drivers resonance frequency. Havent seen an "in box" IR chart tho..

Screenshot_2022-06-11-20-10-34-327_cn.wps.xiaomi.abroad.lite.jpg
 
#27
planet10 said:
I do not expect anything mainstream will have highish Rout

There are such amps that are not ACA or SE tube amp. Less so usually with SS than tube PP.

Firstwatt F1/F2

dave
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Thanks! Are all (or most) PP tubes in this category, or is this rare as well?

Also, what is the benefit of using an amp which has high Rout vs. one that doesnt + resistor?

Can somebody also link to often refered to Pass' article where he discusses this?
 
#28
Most PP tube amps are likely closer to a single ACA, but it is often hard to tell, i have talked to makers that do not even sedaveem to know what Rout is. Not often specified, but sometimes you can get an idea from the damping factor. You would like to see it at something like 2-6 or so.

dave
 
#30
bridger2086 said:
GM refered to, what i think are 70s Pioneer transistor amps that have high enough bias to work in cl.A most of the time?
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Not real 'savvy' WRT electronics, so just going to say not unless it had a high output impedance due to having either output trannies (which can be added to any amp AFAIK) or at least a very low DF to get the 'smiley face' EQ.
 
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#34
Tpa6120 or better ths6012 are low power op amps intended for adsl drive and suitable for 32 ohms headphones , but with horn speakers they have enough power in a normal room using the fostex .This friend of mine has really well machined horns though...
 
#37
Those TPA amps also don't have a high Rout i'm afraid. High Rout amps are now rare and not common availeble, as the trend in the mainstream hifi is class D (very low Rout amps) and multiway low sensitive speakers. Current offers of class A amplifiers are very limited and very expensive (Pass Labs & First Watt are the main brand). In the diy section there is more to offer. The easiest way will be a pair of ACA's in mono bridged modus. The Firstwatt amps are indeed also an option, but harder to source parts if you do a diy and expensive when you buy them build. Some amps like the Marantz PM5004 I work in class A for the first few watts and then go to class AB. I had success with my Marantz PM5004, but it's successor (PM5005) is a different beast and pure class A/B as the topology changed to current feedback.
 
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#39
AllenB said:
Do you know how much resistance you need? It may be possible to use a fixed resistor.
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not sure. i found that Pass' article in which he discusses the topic, i will go through today. I think he mentions 46ohms for fe206e (maybe similar to en version i have).

But the "trick" from dave, using a ultra thin wire seems to be doing the work. Using 5m of 26awg solidcore wire atm.
 
#40
waxx said:
Those TPA amps also don't have a high Rout i'm afraid. High Rout amps are now rare and not common availeble, as the trend in the mainstream hifi is class D (very low Rout amps) and multiway low sensitive speakers. Current offers of class A amplifiers are very limited and very expensive (Pass Labs & First Watt are the main brand). In the diy section there is more to offer. The easiest way will be a pair of ACA's in mono bridged modus. The Firstwatt amps are indeed also an option, but harder to source parts if you do a diy and expensive when you buy them build. Some amps like the Marantz PM5004 I work in class A for the first few watts and then go to class AB. I had success with my Marantz PM5004, but it's successor (PM5005) is a different beast and pure class A/B as the topology changed to current feedback.
Click to expand...

Does class A in some way "guarantee" or "makes it more likely", that there will be high R.out?

Few cues I've learned to look out for:
-low damping factor/high R.out
-no global feedback which seems to be the main culprit for this

That speaks to the single-ended approach, but than i learned that some SE amps have quite low Rout anyway (1-2ohm)

Tripath amps, i've read (hearsay) have quite low Rout at higher frequencies, but raise significantly where this is critical (speaker resonance frq.). Is this true and what is causing it?

As mentiined above, current source amp is what one would want to track speakers impedance, effectivelly bringing both extremes of FR on a fullrange speaker up.

But how does one make sure that the amp "responds" an accurate amount. ie. not over/undercompensating?

If this is the case, it seems to me that such speakers are really designed to work with a specific amplifier?
 
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