mike stehr Posted May 10, 2015 Share Posted May 10, 2015 I've had great results (even with the cheap Chinese unit) using a stepped attenuator direct from a CD player to a tube amplifier. But the Chinese unit would "break before make" when switching between steps, and eventually jammed up and broke altogether. So this time around I spent a few more bucks and went with a Goldpoint Mini-V level control.I'll have to order some RCA input/output jacks, and wire it up, and pimp the enclosure out somehow. I wanted to keep wire length as short as possible, hence the level control mounted in back, with a shaft to the control knob. 2 Quote Link to comment Share on other sites More sharing options...
vnzbd Posted May 10, 2015 Share Posted May 10, 2015 I have been looking into a device such as that as well. I have been looking at the Emotiva "Control Freak", link below. https://emotiva.com/products/electronics/control-freak Can you speaker of any major differences or advantages one unit may have over another? Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted May 10, 2015 Share Posted May 10, 2015 Having built dozens of passive line stages for guys I'll put in my two cents while you're waiting for Mike to get back to you. The advantage of a stepped attenuator is that channel balance at the switch can be very precise. Some also claim that the metal film resistors used sound better than a volume pot does (I have never confirmed that myself). The down side is that the increments of change in level may not suit every listener. Depending on the level at which you want to listen, the stepped unit may be a little too loud or a little too soft, whereas a volume pot allows a more precise level adjustment. Another negative about using a stereo attenuator, or dual volume pot as Emotiva does, is that you cannot balance the two channels at your listening position. Between recordings which are not balanced, room acoustics which can cause an imbalance, and our ears not having identical loudness response, using a single control is a definite disadvantage. A better approach, regardless of whether you use a stepped control or volume pot, is to have separate controls for each channel. That way you can center the soundstage much more precisely. I don't know what type of circuit Emotiva is using but have the impression that it's nothing more than a dual 10k potentiometer. If that's the case, depending on the setting of the control, there may not be a minimum load into which your source will operate. This can lead to distortion with some equipment. If you're handy, you can build your own passive line stage for less money than the Emotiva. Attached is a schematic for an arrangement which ensures that the source will never have a load of less than 10k (this should be fine for most devices as they rarely have an output impedance of more than 0.6 to 1k). Maynard simple-passive-attenuator.pdf 1 Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted May 10, 2015 Share Posted May 10, 2015 Just came across a couple of pictures of a pair of mono passive attenuators, with multiple inputs, which I sold a while back. Regrettably, I don't have one of the internals. Maynard Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted May 11, 2015 Share Posted May 11, 2015 I've had great results (even with the cheap Chinese unit) using a stepped attenuator direct from a CD player to a tube amplifier. But the Chinese unit would "break before make" when switching between steps, and eventually jammed up and broke altogether. So this time around I spent a few more bucks and went with a Goldpoint Mini-V level control. I'll have to order some RCA input/output jacks, and wire it up, and pimp the enclosure out somehow. I wanted to keep wire length as short as possible, hence the level control mounted in back, with a shaft to the control knob. 004.JPG 002.JPG 003.JPG Mike, Seti might be of help to you....... tc Quote Link to comment Share on other sites More sharing options...
minermark Posted May 11, 2015 Share Posted May 11, 2015 I've had great results (even with the cheap Chinese unit) using a stepped attenuator direct from a CD player to a tube amplifier. But the Chinese unit would "break before make" when switching between steps, and eventually jammed up and broke altogether. So this time around I spent a few more bucks and went with a Goldpoint Mini-V level control. I'll have to order some RCA input/output jacks, and wire it up, and pimp the enclosure out somehow. I wanted to keep wire length as short as possible, hence the level control mounted in back, with a shaft to the control knob. 004.JPG 002.JPG 003.JPG I like first class quality parts and work. share where you got that Pre-loaded rotoryswitch please. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted May 11, 2015 Share Posted May 11, 2015 I've had great results (even with the cheap Chinese unit) using a stepped attenuator direct from a CD player to a tube amplifier. But the Chinese unit would "break before make" when switching between steps, and eventually jammed up and broke altogether. So this time around I spent a few more bucks and went with a Goldpoint Mini-V level control. I'll have to order some RCA input/output jacks, and wire it up, and pimp the enclosure out somehow. I wanted to keep wire length as short as possible, hence the level control mounted in back, with a shaft to the control knob. 004.JPG 002.JPG 003.JPG I like first class quality parts and work. share where you got that Pre-loaded rotoryswitch please. http://www.goldpt.com/ Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted May 11, 2015 Share Posted May 11, 2015 Having built dozens of passive line stages for guys I'll put in my two cents while you're waiting for Mike to get back to you. The advantage of a stepped attenuator is that channel balance at the switch can be very precise. Some also claim that the metal film resistors used sound better than a volume pot does (I have never confirmed that myself). The down side is that the increments of change in level may not suit every listener. Depending on the level at which you want to listen, the stepped unit may be a little too loud or a little too soft, whereas a volume pot allows a more precise level adjustment. Another negative about using a stereo attenuator, or dual volume pot as Emotiva does, is that you cannot balance the two channels at your listening position. Between recordings which are not balanced, room acoustics which can cause an imbalance, and our ears not having identical loudness response, using a single control is a definite disadvantage. A better approach, regardless of whether you use a stepped control or volume pot, is to have separate controls for each channel. That way you can center the soundstage much more precisely. I don't know what type of circuit Emotiva is using but have the impression that it's nothing more than a dual 10k potentiometer. If that's the case, depending on the setting of the control, there may not be a minimum load into which your source will operate. This can lead to distortion with some equipment. If you're handy, you can build your own passive line stage for less money than the Emotiva. Attached is a schematic for an arrangement which ensures that the source will never have a load of less than 10k (this should be fine for most devices as they rarely have an output impedance of more than 0.6 to 1k). Maynard The problem I'm finding with this approach Maynard, is that I spend more time going back and forth trying to get each channel level matched and don't actually listen to the music. I'd much rather have the volume pots set to 12 o'clock (or whatever is appropriate to the DAC output) and one of these between the DAC and amp for volume adjustments: http://www.tisburyaudio.co.uk/mini-passive-preamplifier but you're saying that's a bad idea? Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted May 11, 2015 Share Posted May 11, 2015 Hi Michael- was about to head for the shop when I saw your post come in! It shouldn't take long to adjust the individual volume pots unless you're trying to center the soundstage perfectly. It's one thing to do that for serious listening, but for casual listening while working you can just set them to approximately the same position and it should be close enough. Regarding adding the passive device between the DAC and the amp, doesn't your unit have variable output? If so, set the volume controls of the amp to establish the initial balance, and then use the DAC to change level. The less stuff in the signal chain the better. Drop me an email if you want to go into more detail on this. Enjoy- Maynard Quote Link to comment Share on other sites More sharing options...
Thaddeus Smith Posted May 11, 2015 Share Posted May 11, 2015 Hi Michael- was about to head for the shop when I saw your post come in! It shouldn't take long to adjust the individual volume pots unless you're trying to center the soundstage perfectly. It's one thing to do that for serious listening, but for casual listening while working you can just set them to approximately the same position and it should be close enough. Regarding adding the passive device between the DAC and the amp, doesn't your unit have variable output? If so, set the volume controls of the amp to establish the initial balance, and then use the DAC to change level. The less stuff in the signal chain the better. Drop me an email if you want to go into more detail on this. Enjoy- Maynard Old news, sold that device last week due to some funky compatibility issues. Replacement DAC's that I'm looking at are more of a traditional source device and don't have variable output and I guess my point is that source levels often change from album to album, of which I regularly cycle during my listening sessions - I have music ADHD. chat when you have time, none of this is urgent. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted May 12, 2015 Author Share Posted May 12, 2015 I've had great results (even with the cheap Chinese unit) using a stepped attenuator direct from a CD player to a tube amplifier. But the Chinese unit would "break before make" when switching between steps, and eventually jammed up and broke altogether. So this time around I spent a few more bucks and went with a Goldpoint Mini-V level control. I'll have to order some RCA input/output jacks, and wire it up, and pimp the enclosure out somehow. I wanted to keep wire length as short as possible, hence the level control mounted in back, with a shaft to the control knob. 004.JPG 002.JPG 003.JPG Mike, Seti might be of help to you....... tc Er, how? Quote Link to comment Share on other sites More sharing options...
mike stehr Posted May 12, 2015 Author Share Posted May 12, 2015 (edited) I have used CD players that have a volume control on the remote, (my Heart/Marantz has it) but the issue I had was you couldn't turn the volume all the way down. I had used a pair of Allen Bradley "type J" 60K pots for left and right volume control. Basically two pots lashed up in a wooden box with jacks...worked out fine... Edited May 12, 2015 by mike stehr Quote Link to comment Share on other sites More sharing options...
seti Posted May 12, 2015 Share Posted May 12, 2015 (edited) I've had great results (even with the cheap Chinese unit) using a stepped attenuator direct from a CD player to a tube amplifier. But the Chinese unit would "break before make" when switching between steps, and eventually jammed up and broke altogether. So this time around I spent a few more bucks and went with a Goldpoint Mini-V level control. I'll have to order some RCA input/output jacks, and wire it up, and pimp the enclosure out somehow. I wanted to keep wire length as short as possible, hence the level control mounted in back, with a shaft to the control knob. 004.JPG 002.JPG 003.JPG Mike, Seti might be of help to you....... tc Er, how? That is what I was wondering. Still having issues with myself lol.... Did you drop the autoformers? I'm curious what issues you might have had. Edited May 12, 2015 by seti Quote Link to comment Share on other sites More sharing options...
mike stehr Posted May 13, 2015 Author Share Posted May 13, 2015 (edited) I've had great results (even with the cheap Chinese unit) using a stepped attenuator direct from a CD player to a tube amplifier. But the Chinese unit would "break before make" when switching between steps, and eventually jammed up and broke altogether. So this time around I spent a few more bucks and went with a Goldpoint Mini-V level control. I'll have to order some RCA input/output jacks, and wire it up, and pimp the enclosure out somehow. I wanted to keep wire length as short as possible, hence the level control mounted in back, with a shaft to the control knob. 004.JPG 002.JPG 003.JPG Mike, Seti might be of help to you....... tc Er, how? That is what I was wondering. Still having issues with myself lol.... Did you drop the autoformers? I'm curious what issues you might have had. Yes, I got broke last winter and a forum member bought them for a good price...I hope he is happy with them... The issue I had was the autoformer VC set-up had weak bass, even after re-stacking for maximum bass. I don't know if I had them connected correctly, but I'm pretty certain I had. I dunno if the application I was using them for (after a CD player and before a tube amplifier) was the proper way to use them. I used several tube amps with the autoformers, and came with the same results: lack of bass and slight ringing/saturation sort of sound. In spite of that, the midrange and top-end was awesome sounding. I'm not knocking the product, many really enjoy the autoformers, and I like Slagle and all the Joenet boys. But the autoformers just didn't do it for me...even though I'm curious enough to give them another try some day. Edited May 13, 2015 by mike stehr Quote Link to comment Share on other sites More sharing options...
seti Posted May 13, 2015 Share Posted May 13, 2015 I've had great results (even with the cheap Chinese unit) using a stepped attenuator direct from a CD player to a tube amplifier. But the Chinese unit would "break before make" when switching between steps, and eventually jammed up and broke altogether. So this time around I spent a few more bucks and went with a Goldpoint Mini-V level control. I'll have to order some RCA input/output jacks, and wire it up, and pimp the enclosure out somehow. I wanted to keep wire length as short as possible, hence the level control mounted in back, with a shaft to the control knob. 004.JPG 002.JPG 003.JPG Mike, Seti might be of help to you....... tc Er, how? That is what I was wondering. Still having issues with myself lol.... Did you drop the autoformers? I'm curious what issues you might have had. Yes, I got broke last winter and a forum member bought them for a good price...I hope he is happy with them... The issue I had was the autoformer VC set-up had weak bass, even after re-stacking for maximum bass. I don't know if I had them connected correctly, but I'm pretty certain I had. I dunno if the application I was using them for (after a CD player and before a tube amplifier) was the proper way to use them. I used several tube amps with the autoformers, and came with the same results: lack of bass and slight ringing/saturation sort of sound. In spite of that, the midrange and top-end was awesome sounding. I'm not knocking the product, many really enjoy the autoformers, and I like Slagle and all the Joenet boys. But the autoformers just didn't do it for me...even though I'm curious enough to give them another try some day. That is interesting. Dang I would have bought them from you 8-) I use mine between music server, cdp, and wright phono and tube amp. This was without issues. It was night and day difference for me. Project looks good! Quote Link to comment Share on other sites More sharing options...
mike stehr Posted June 8, 2015 Author Share Posted June 8, 2015 Finished finally. Been busy working lately, weather is nice, etc... Nothing special...just a enclosure I bought for when I had the autoformers. 30 bucks from eBay... The shaft and coupler are parts pinched from a old Tek scope, the bracket for the attenuator is hand fabricated, and the knob is pinched from a FM signal generator...I think... The female RCA jacks are Connex, the wire is 22 AWG Jupiter. I wanted to keep wire length to minimum, and I think I didn't do too bad. I used the attenuator after my Marantz/Heart CD player, and into my Magnavox SEP 6BQ5 console amplifier, hooked up to my Cornwalls. No more pops and clicks like the cheap stepped attenuator I had. Works very well, with nice action when adjusting steps. Channel balance is rather surprising. It just attenuates the volume...no sound of it's own. If it's a crummy recorded ceedee, you'll know it. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted June 8, 2015 Share Posted June 8, 2015 Looks really nice Mike! Was that enclosure pre-painted or did you do it yourself? And, is it aluminum or steel? Maynard Quote Link to comment Share on other sites More sharing options...
LarryC Posted June 8, 2015 Share Posted June 8, 2015 (edited) The down side is that the increments of change in level may not suit every listener. Depending on the level at which you want to listen, the stepped unit may be a little too loud or a little too soft, whereas a volume pot allows a more precise level adjustment. That is what I ran across with a CAT preamp, which showed up as follows: - The number of steps was limited, to only 26 IIRC, which meant that some of the steps had to be pretty wide -- 6 db instead of 2 or 3 per step -- in order to get enough attenuation. The old Marantz VC had 80 db of attenuation as I recall. - It's designer choice whether the wide steps go at the top or the bottom of the VC range, and since the K-horn efficiency kept the VC at the bottom, the wide steps had to go to the top. Wide steps at the bottom are a problem with high efficiency and high amplifier gain. This is an issue of gain matching between speaker efficiency, amplifier gain, and the line stage of the preamp (since volume controls tend to be located after the phono stage but before the line stage). VC's also have sweeter-sounding parts of their range, and you want yours to generally sit where they sound their best. Edited June 8, 2015 by LarryC Quote Link to comment Share on other sites More sharing options...
mike stehr Posted June 9, 2015 Author Share Posted June 9, 2015 (edited) Looks really nice Mike! Was that enclosure pre-painted or did you do it yourself? And, is it aluminum or steel? Maynard Thanks Maynard! The top and bottom are pre-painted steel, (black) and the end caps are aluminum...which I painted semi-gloss back. If I ever get some extra time, I'm going to try bread-boarding the single-ended 6V6 mono amplifiers you started a thread with...eventually... Edited June 9, 2015 by mike stehr Quote Link to comment Share on other sites More sharing options...
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