Video

A toaster with big meters!

Thanks so much more the question, but those are 27" computer monitors for my workbench PC. I have never owned any Dalquist speakers.

First, thanks so much for sharing your comments! I Agree with you about the whole VU thing. They are not power meters and do not show watts. But they can be useful to do a quick matching to set the amplifier output levels at say 1khz that would be going into each speaker- easier than hooking up a DMM for most folks. You are obviously technically inclined. I like when your amp gives you a choice of whether you want a peak meter response or average, on a "hold peak for a while" (or LEDs if that is what is used). I would say that up to the current handling capability of the ET30, your sound is pretty much not going to be affected from what the data showed.

@@vintageaudioreview I'm on a mission to correct the misuse of "VU" for what are or should be Power meters. Even back in the day VU was misused with even better display's like Peak Sample and Hold. VU was only used to assure uniform display in the way way back days. But with people willing to spend $10k or more on speaker cables to provide the most direct signal transfer from the amp, all those extra connectors, relays, ...

@@glenncurry3041 I remember reading threads about the mis-use of VU meters on the ASR site, and it was in regard to a device like the ET30. I actually just finished sending an email to Neohipo based on your comments, about making it an actual power meter with a switch to set for 20w or 200w (8ohms) ranges and not have the controls. My guess is that folks who spend $10k for speaker cables have no need for a device like the ET30 as they should have a room dedicated to each of their systems.

@@vintageaudioreview You might check the source names. It might have been me. I've posted a number of times when I see these things. These are mislabeled voltage meters. Ever relabeling them to Watts based on 8 ohms is not technically accurate. True power meters monitor the voltage and current in relevant phases. Like the AC Meter on houses. But yes, likely a dual 4 ohm and 8 ohm set of scales would at least be meaningful.

@@glenncurry3041 The person I emailed the suggestions to thought it was a good idea and passed the suggestion onto the engineering team. I have designed a few LED power meters, which strictly measured the voltage across the load, and were ok for what they are. My 1st attempt at designing one using big blue meters failed and set me back about $200, though I may try another approach at some point in time...I like displays

I started of with the Little Bear- actual returned one and got another one a month or so later. They have a low frequency boost at 20hz if I remember correctly- probably less than 1dB, but I did not think something I would be using for a/b'ing should have that and returned it. I wrote a paper on my measurements which I posted to the ASR website. But for most folks, that is not going to be a factor. Thanks for watching and commenting as always!

@vintageaudioreview I believe I watched your review or reporting on the One Little Bear. I believe you mentioned a .4 dB rise at the frequency extremes? I don't remember for sure. When I got the One Little Bear in my system, I tried to hear any issues with the sound, but I did not hear any difference. I, too, had to exchange for another unit due to the meter operation barely moving. The free replacement One Little Bear has been working fine for about 2 years now. I do like the larger size and additional features of your review unit. I would probably purchase it when the time comes. Thanks for your great review!

@@vintageaudioreview I just bought one!

@@scottbennett3119 I only did a write up for the Douk unit, and I just read it and it actually has 1dB of gain at 20hz. My guess is that it is caused by the transformer they have installed as part of the VU meter circuit. I wrote them and they got back to me and told me to look to see if the unit I had was configured with certain parts indicating a change to fix the problem had been made, and it had, so I returned it to Amazon again. For most folks it is not a big deal, but for what I do, it was unacceptable. I do not think that I've done a video on the switcher that I use now, but did a write up which I also posted on the ASR site. I really like the ET30, but don't have a need for it with my systems, but my buddy Ian does so he has it (trade credit for some piece of gear of his 😃) and really enjoys being able to switch between two amps and two speakers

@vintageaudioreview I said earlier you did either a review or report, as I couldn't remember exactly which it was. Anyway, I went ahead and bought the unit today because of your enthusiastic review today...

I appreciate you watching and taking a few moments to comment. If you have the need to switch between two amps and two speakers it is a great choice!

Yes , speaker switching was my use. You know I seem to gather mid range 80s speakers , I need to weed out

@@ragnarhairybreeks If they work and sound good, find a place for them 😁

Thanks for the comment. It would show a more accurate dB change when the power levels were less than I think 26w/8ohms, but as you were at a higher power level, say 52w/8ohms, the change was not 3dB- which is what I showed. If I then adjusted the control on the Left "Swing Range" so that it was at 0dB and then went to 104w/8ohms, maybe it would have shown a +3dB change.. but I did not do that, though it would have been another interesting test. Could have also went down to 26w/8ohms again and see if it was -3dB....I appreciate your suggestion.

Thanks for taking the time to let me know you liked it!

Thanks you for taking the time to comment. I would not regard it as an historic amplifier though. I went back and looked at the raw footage and pictures I took and did not see any cooked resistors. It looked decent at the lower power levels. Not the best performing amp at higher power levels- at least this one....

I love hearing about gears that is still working great after so many years of use- thanks for sharing! The amps should be an easy fix I would think

Thanks so much for watching and the suggestion. I did mention in one of my earlier responses that for my next a/b get together test, it will be between vintage receivers. Ian (seen at the end of the video), has several vintage receivers to choose from. He will provide me 3 and will not know which two I use until after the test, and no-one else will know what the potential choices are. I will have tested all of them and done a video on the choices. I am guessing there will be a Sansui among them. This event will be in mid October if all goes well, with the video up in November.

Thanks for the comment/question. I stated in the video, towards the end, that B was the T9 and the Marantz was C.

​@@vintageaudioreviewit would have interesting to know as a viewer which way the participants were leaning. Got it at the end but lost interest during the tester remarks section.

@@brunoespinosa5907 Thanks for you suggestion. I like putting the participants in the video- I think they get a kick out of it and it just shows I am not pulling this out of the air. I doubt we would ever get more than 15folks, and one guy does not want to be on CZcams (he was not at this event). At 19:38 in the video I did read the questionnaire summary results.

@@vintageaudioreview I do appreciate the reviewers candid impression and think it's a part of a very important step of verification of the authenticity of the results, please keep this part in upcoming posts! Those who may not be interested may simply skip this part~

@@ericlo6370 As I mentioned to someone- maybe it was you (there have been a lot of comments on this video, which is good, but does take some time for me to respond) the participants, most but not all I have met before, like to have me ask for their comments for the video, though not all of them have seen it yet.

Thanks for the comment. Am not sure what complimenting the speakers would have required as both amps were able to drive them pretty easily for the levels we needed. Some folks believe that horn speakers can sound less harsh with tube amps, but I have not found that with my listening tests.

I have the A08 pro as well, and both of them sound great when paired with efficient speakers- always put your money into the speakers 1st. Aiyima maybe me sending another amp to test before too long.

@@vintageaudioreview Interestingly, I bought an A07max but the difference is not small and A07max is now sitting beside my A08pro gathering dust....

@@vintageaudioreview btw, I'm driving it with a pair of notoriously hard to drive Dynaudio Crafft speakers with 86dB but still gives out respectable sound!

@@ericlo6370 Am not familiar with your speakers, but 86dB is a bit on the lower side. As long as you are liking the sound, you should be 😁

@@vintageaudioreview Crafft is a consumer version of Dynaudioacoustics C2 studio speakers, using a pair first generation Esotar which the sound is truly remarkable even in today's standard! That said, you should also give a try on a truly amazing little amp by PJ Miaolai A7 which was said by Doctor John that it took the throne away from Aiyima T9. Lower powere but more involving sound~ I'm using their A4 (same as Douk U4 which was raved by Jeff Day of Positive Feedback ) which got everything A7 has except the amp section, amazing little unit with a take no prsioner attitude!!

I have not seen a schematic or block diagram, but based on the fact that the T9's Aux out shows the even harmonics higher than the odd, I would guess the tubes are a buffer in the preamp stage. Tubes do provide amplification!

The tubes will typically be in a Cathode Follower configuration (do a search). They won't provide gain, but the "tube effect" will be somewhat present.

@@Douglas_Blake_579 I was thinking @craigenputtock was making a general statement about tubes not being able to amplify signals, but re-reading the comment it may have been just for the T9...

@@vintageaudioreview Tubes certainly can produce gain ... gobs of it! But at the low voltages provided by boost converters in these pre-amps the tubes are just barely on, so their gain is substantially limited. Thus cathode followers ... the equivalent of an emitter follower in a transistor circuit. The tube is passing the waveform, but will not produce voltage gain.

@@Douglas_Blake_579 Too bad there is no schematic for it- that I have found.

Thanks for the comment. Speakers are pretty good. Speaker cables are 12guage and both the same for each amp as are the RCA cables going to each from the preamp. Room is not the best acoustically, but how many are? Strictly a quick test to see if there was an obvious difference between the two, and there really was not for the most part.

@@vintageaudioreview Thanks for the reply! No doubt all components are good. What i meant - with cheaper speakers and bad, thin cables the result would be more obvious : i hope vintage amp would show its pedigree and much better score even with those mass production components. Thanks again

@@leodvosis No problem and now I get what you were saying. 16gauge copper "zip cord" speaker will will do fine for most folks needs and either of the amps, but I go with the thicker wire to eliminate any doubt (at least for most reasonable folks). Find speakers that YOU like the sound of and can afford and you will be happy with most any decent amp as long as it can drive them...

Good catch and thanks for paying attention to the data! I noticed that too and I believe that was when I was approaching the max output power of the T9 the SNR dropped as the noise floor went up quite a bit. Not sure if it was in the preamp stage which I assume uses the tubes or the chip amp itself. I could have looked at the preamp output I suppose (I don't remember if I did that in the T9 episode). But at max power playing most music I listen too in a decent set of speakers, you will most likely not hear the increased noise I am guessing.

@@vintageaudioreview Something to bear in mind here is that the old clipping target of 1% distortion used with vintage gear is going to be well beyond the clipping level of this newer class D stuff. The reason being that older gear, either through aging or limitations of the design, starts out with significantly more distortion. As you know I've added clipping and protection indicators to a few TPA3255 based amplifiers and the chip's clipping light typically comes on at about 0.1% distortion which, unlike AB amps, is actually visible on an oscilloscope.

@@Douglas_Blake_579 Great comments as always. It seems that the 1% distortion at max power is a newer spec by the CEA (?) standards where there was no such rating with the older IHF specs. Interesting that you can see the clipping at .15 THD. When I get done trying to measure DC on AC I may hook up the scope to the A07 and look at clipping 😃

@@vintageaudioreview Keep in mind that these Class D amps are running in BTL (Bridged) mode so both speaker poles are active. This however gives us a chance to see the behaviour at clipping very clearly ... Measure only one pole of the output against ground. As the output approaches waveform clipping you'll see some "fuzzy" trace effects at the peaks of the waveform. That is Class D clipping... it's inserting very narrow pulses to prevent the PWM carrier from reaching pulse-widths of zero. But don't worry ... the fuzzies are in phase for both poles of the bridge so they produce no output. If you then read the signal differentially you will see waveform clipping but not the "fuzzies". You will also notice there's a fair bit of difference in the two levels. PWM safety pulses begin at about 99% of waveform clipping levels, which is just below that conventional "knee" point where you see distortion rise dramatically... and considerably less than 1% distortion. What you can deduce from that is that Class D clipping is far more managed than Class AB clipping. Allowing it to clip conventionally could result in shut-downs in the PWM carrier which, in turn, could make some very strange, very loud noises until it recovers.

@@Douglas_Blake_579 I will give this a try at some point- I appreciate the info!

Thanks for the comments as always. Even though there was beer, only a few of us had any and I had maybe two or 3 over a 4hr period. Everyone took the test seriously, and a few even did it twice. And they almost always comment that they learn something and enjoy doing them. They are also told not to discuss the test with those that had not yet taken it.

I do like the vintage Marantz receivers and they do look great and sound fine and why not spend your hard earned $$'s on something you want 😆

Thanks for the comments Chris! The T9 did have a bit of a treble bump that I pointed out in the data, but could have been adjusted slightly with the treble control I suppose though I tried to make sure it was as flat as I could get it w/out the midrange suffering more. There are some speaker reviews that I have watched that seem to indicate that manufacturers may adjust the sound from flat to a boost here and there based on market research..... I think I get more fatigued by certain music that is being played more than by the gear....when I am at a friend's place.

Thanks for taking the time to leave comments. The A07 can be improved if you are so inclined, but for a lot of folks it is great. I reviewed mine a ways back. I have not proved to myself that there is a difference between tube and ss sound- you certainly can see it in measurements, but not sure you can really hear it on decent amps of either design. Not familiar with the A3 right off the bat.

@@vintageaudioreview I had a very good tube class A amp (2 x 30 watt in A) DC coupled and THD 0,35% which is realy good for a tube amp. It had a very bass control about the high damping factor and sounded very close to the A07, maybe a bit more dynamic but in general not far of. If well implemennted they should sound simular.. a think a lot depend about the bass control, damping factor which can make the sound in general more muddy and alterate the balans.. my two cents ;-)

@@birdyflying4240 Possibly you meant to say "variable bass control and a high damping factor" ?

@@vintageaudioreview i meant: a very good bass control (like a good AB amp) which is not common for a class A tube amp...

Many thanks for the comment. Good eye on the 250's- they used to be in Richard's bedroom, but his girlfriend must have said only 2 pairs of speakers are allowed in there. If they are not attached to anything I am sure he will let me use them for as long as I need to- so look for them in an upcoming video thanks for the request!

Thanks for the comment and I try to do different things topics now and then. If you ever want to participate in one of these get togethers contact Ian and let him know- we may have one in October sometime.

Thanks for taking the time to let me know!

I’m not knowledgeable about such things, but I’ll guess you considered an a,b,x comparison set up? Where x is either a or b

@@ragnarhairybreeks You are indeed correct. I don't have the test box that allows for that- they are around $1200. I think my method works pretty well so you can see if one of your choices is consistent with others taking the test, at least for the sample size.....

Thanks for the comment and hearing is of course, but so are measurements 😄

Thanks for the comment and these tests are always fun and a bit insightful...

AS always, thanks for watching and the comments. I think for the next test we are going to a/b some vintage receivers........

@@vintageaudioreview That should be interesting. The one I'd really like to see is the Aiyima A07 (original) vs a solid state Class AB amp. You know, the classic ... $100 vs $1,000 battle.

@@Douglas_Blake_579 As I have the original A07 (I think), it could be done at some point....

@@vintageaudioreview Cool. The original A07 is still the king of the Chi-Fi amps.

@@Douglas_Blake_579 Hi Douglas, I stand by my A08pro over 07, more musically tuned I think, but both are good products ~

Thanks for taking the time to tell me more about the Sansui, which is now mine. I counted about 4 secs of muting too (in the video) so am not sure why I said 16seconds. I had downloaded the service manual- a few versions of it actually- but the muting adjustment was under "Delay adjustment of the E2 signal", which I would have had to have read if I thought it was a problem. Not sure how I missed the flashing LED just been an indicator as to what is going on and not used for the detection of the groove content.

Thanks for the comment. I did an a/b against a preamp from high end audio brand which will be mentioned in an upcoming video.

Thanks for the question, but I have no idea. Years ago- maybe the 70's and 80's, you may have seen and add for a piece of audio gear that touted how many stages of amplification it has, but that seems to be rare these days, and ML schematics are hard to come by. There are pros and cons to having say a few stages with a lot of gain or sevaral with lower gains....

It is not a Goodwill find. I am not sure where I got it- most likely from Ebay many years ago...

I was unable to find the schematics or service manual for it either 🙁

My buddy wished it were worth that much!

Thanks for sharing. I am assuming that you had it recapped rather than doing it yourself as it appears to be quite the undertaking and for that amp as PM, definitely a good idea. At least you have the MC462 in your stable!

Yes, it was serviced by a ML authorized repair shop in CA. This is what was replaced. All ML parts. Boards were in top shape. 4 x ML-19000uf - 150v cap 4 x ML-50000uf - 125v cap 4 x ML 200224 150uf cap 4 x ML 200017 680uf cap 12 x ML LT1097 Transistor 20 x ML- 16165 .01uf cap 3 x ML - 110087 - UR resistors 6 x ML 200013 68uf cap 3 x 30AGC Fuse 4 x ML 200046-3300 22uf cap

@@henrymagallon8578 Thanks for all the info- but you did not say the cost... $3500 ? I assume you did lived in the area and did not have to pay for shipping ?

I drove 500 miles to get them serviced. The total cost for the work was $2,847.

@@henrymagallon8578 That is dedication!

Thanks for taking a few moments out of your schedule to give me feedback. I like to be able to "mix it up" a bit with my videos. When I hit 3000 subscribers- probably around October- I will do a live feed and hope you will join in.

Absolutely, I would very much like to participate! That will be a great time. I'm looking forward to it. Thanks!

@@scottbennett3119 My only other live stream which was back in March or April, only had one other person on line with me- and he stayed the whole 1/2 hour so that was nice of him. I had to pull down the video as my wife came in at the very end and had been working outside in the dirt so took off her pants and she came in through the door to my room where the livestream was- in her underwear- I have since changed the angle of my webcam so the door is not seen. I went to edit that part of the video out, but the chatbox comments were not there so it was deleted........

Lol! I can totally relate to the wife coming in dirty and overheated from gardening! What a time that must have been! Thanks for sharing..

Love the comment, and probably so to a certain extent- but never with my audio friends back in the day. Now a days, with DSP, I don't think it is frowned upon so much at all. With judicial use of the EQ- where you boost within the limits of the EQ's distortion limits- I don't think there should be any problems. I have a similar EQ from Kenwood that I will remove from another system at some point for a review.

I do not have a schematic for it so can't say if it is direct coupled or not, but point well taken. I strictly use it as a graphic display of the frequency- I like meters and such as you know. The C48 has a 5band eq which is enough for me, plus two main outputs, one of which goes to the BSR. Thanks as always, Douglas!

Indeed!

Thanks for taking the time to let me know that you liked it. Hopefully you will find a 250 that is affordable.

Thanks so much for the feedback!

Thanks so much for taking the time to share your thoughts. We are about the same age. Glad you kept your 2505. The MC7200 I reviewed a ways back did not have the output xformers. I am not a big believer in "tube" sound from what I have done a/b testing on- see the one video where I did an a/b test between solid state and tube amps. They typically measure different, but can't always translate that to a sonic difference. You will meet some of my audio friends in about 2weeks where we do an a/b test....

Glad you got a great deal. An upcoming a/b test may include the 2000a. thanks so much for sharing!

Thanks so much for letting me know you find the videos useful. With some luck you may end up with one of these..but wait a few weeks for a video that may surprise you..

@@vintageaudioreview Can't wait for the surprise!!! You do great stuff!

@@chrisblock6697 It is an a/b video- I am curious what the responses will be...

I would call them a 4ohm speaker to be safe. I can't recommend a center channel speaker since I am not overly familiar with those, other than finding another NS monitor speaker

@@vintageaudioreview thanks for Reaktion this speakers marked as 6 ohm connect with a yamaha 3030 av reciver got alot of Power must confess sounds not so lout

@@HansjorgBiermann-qg5pj They are not the most efficient speakers so that is why it may not be as loud as what you would like

Thanks for the nice comment and question. As far as favorite amp, preamp and receiver, I don't really have one that i would consider a favorite. I have 3 systems in 3 different rooms that I listen to at various times, and they all do a decent job. Actually, in one room I have a couple of different speaker/amplifier combos to chose from, one of them using a Marantz 4430 quad receiver hooked up to a Panasonic quad 8track and Energy bookshelf speakers that is fun to listen to from time to time. It is kinda like asking who is your favorite kid....

Thanks so much for bringing it to me... and the Tequila....

Thanks for taking the time to comment! I am fortunate to have friends that collect (hoard 😄) gear and testing electrical things is what I did for a living, plus I like audio so it is working out well in my retirement. I do test some new things as well on occasion, but my focus is on the older stuff.

Thanks for taking the time to let me know that. I am pretty sure the tubes are not- it performed very well for being old, but that is why folks like vintage Marantz.