Biyang - AD-7 Analog Delay

juanro · Post by **juanro** » 14 Oct 2011, 23:11

Hi,

There was some talk about Biyang delays here, but I couldn't find some actual pictures. So, here it is:

(Pictures in Picasa Web Album)

IC = PT2399, SA571, 4558, 78L05
Trans = (2S)K30A, some three-legged component near SA571 says "H F"?

It is true bypass.

Not worth much of a trace, isn't it? But, anyway, if you want some more pictures, just ask.

Juanro

roseblood11 · Post by **roseblood11** » 15 Oct 2011, 05:18

a pt-80 clone, I guess.

Dirk_Hendrik · Post by **Dirk_Hendrik** » 15 Oct 2011, 06:05

roseblood11 wrote:a pt-80 clone, I guess.

Careful with remarks like this. They're similar to calling every dist with clippers in the feedback loop a TS clone.

The setup of compressor, filter, delay line, filter, expander for delay pedals is extremely common. Therefore when the delayline in that setup is replaced from a BBD chip by a PT2399 delay line doesn't automatically make it a PT80 clone.

Upsairs I have a EH DMM with the MN3005's bypassed and replaced by PT's. Does that make it a PT80 clone?

roseblood11 · Post by **roseblood11** » 15 Oct 2011, 07:13

I owned an AD-8 for 2 days...

uncleboko · Post by **uncleboko** » 15 Oct 2011, 07:43

"La única verdad es la realidad"

roseblood11 · Post by **roseblood11** » 15 Oct 2011, 11:31

Most (or all?) Biyangs are clones. The Overdrive is a Tube Screamer, the Chorus a CE-2, the Phaser a MXR Phase 100...
In my opinion, only the Phaser is really interesting for solder jockeys, because it's not easy to clone the P100 and the parts are quite expensive. All other Biyang pedals aren't bad, but for me the enclosures are to big.

juanro · Post by **juanro** » 15 Oct 2011, 12:49

The enclosure is what I like most of this pedal... and the chickenhead knobs.

Is there a way to know SMD caps values? I can't read anything.

Juanro

roseblood11 · Post by **roseblood11** » 15 Oct 2011, 16:51

Isn#t there a numerical code?

HEAD · Post by **HEAD** » 15 Oct 2011, 17:06

roseblood11 wrote:Isn#t there a numerical code?

Nope. Most likely not.

Dirk_Hendrik · Post by **Dirk_Hendrik** » 15 Oct 2011, 17:42

Easiest is still desoldering and measuring.
Since my Fluke is quite unreliable in the pF range for those measurements I usually build up a small oscillator, use a series of known cap values to mesure the output frequency, plot these as a graph in excel and then insert the SMD caps. The frequency against the graph gives a pretty good impression of the value.

juanro · Post by **juanro** » 15 Oct 2011, 17:53

Well, if it involves desoldering then it's out of the question.
Regarding the circuit: (pt80 clone?) the string of 10k resistors near the transistor (HF??) in the way from pt2399 to sa571 and some other R values seems to indicate that this is true. If it's not a straight clone, it's a very simillar implementation of filter type and values (around pt2399, single transistor 3rd order low pass, and so on)
The time range switch is implemented with a resistor paralel to the time pot. (In the delay I did "Delay80+" I used a similar short/long switch but adding a resistor in series)
The "true bypass" in this case I think is not a good thing... I prefer my way, jejeje, a buffer with tails.
The 2SK30 fet seems to be the millenium bypass indicator.

Juanro

PS: I've put the pictures in Picasa because they're rather big... do you think I should resize and upload them here?

Scruffie · Post by **Scruffie** » 15 Oct 2011, 18:13

Out of interest, do you know what the trimmer's for? My friend was complaining his Biyang had a bad case of run away repeats so i'm wondering if that can be used to dial them out.

juanro · Post by **juanro** » 15 Oct 2011, 18:20

Yes, the trimmer is for setting the max feedback. Anyway: mine also does that runaway... when it starts to auto-oscillate it grows in volumen and it's much louder than the standar repeats. If I move the trimmer, then it doesn't do that anymore - but also does not auto-oscillates.

Juanro

Liquitone · Post by **Liquitone** » 11 Sep 2013, 13:15

Does anyone have information on whether the Akai Analog Custom Shop Analog Delay is identical to the Biyang AD-7 ? preferebly with a link to gutshots of the Akai? as I can't find any.

theehman · Post by **theehman** » 11 Sep 2013, 13:51

Liquitone wrote:Does anyone have information on whether the Akai Analog Custom Shop Analog Delay is identical to the Biyang AD-7 ? preferebly with a link to gutshots of the Akai? as I can't find any.

I'm betting it is. I bought the Akai Professional Analog Custom Shop Quad-Mode Phase Shifter and from the outside at least it looks like it's identical to the Biyang PH-8

Liquitone · Post by **Liquitone** » 11 Sep 2013, 14:02

Yeah I am very suspicious about it as well. from the outside they look exactly the same, but would like this confirmed. It says 'Analog' on the pedal and on the box it says; true analog bucket brigade design for vintage sound', but I would be surprised if the guts wouldn't show the same PT2399 as in the Biyang.

roseblood11 · Post by **roseblood11** » 11 Sep 2013, 20:06

I'm pretty sure that the AD-7 was sold as "Akai" and "Collins" as well.

NiteGoat · Post by **NiteGoat** » 13 Sep 2013, 22:04

Liquitone wrote:Does anyone have information on whether the Akai Analog Custom Shop Analog Delay is identical to the Biyang AD-7 ? preferebly with a link to gutshots of the Akai? as I can't find any.

I just got off of the phone with tech support at Akai. The person I spoke with that that there is indeed a BBD chip in their custom shop analog delay. He said he wasn't sure which one it was, but told me that if I were to open up the pedal I would see a BBD chip. He played dumb when confronted with the question about them being manufactured by Biyang and rebranded with Akai graphics. So now I'm torn between just buying the Biyang AD-7 or the Akai.

NiteGoat · Post by **NiteGoat** » 13 Sep 2013, 22:10

Liquitone wrote:Yeah I am very suspicious about it as well. from the outside they look exactly the same, but would like this confirmed. It says 'Analog' on the pedal and on the box it says; true analog bucket brigade design for vintage sound', but I would be surprised if the guts wouldn't show the same PT2399 as in the Biyang.

I just got off of the phone with tech support at Akai. The person I spoke with said that there is indeed a BBD chip in their custom shop analog delay. He said he wasn't sure which one it was, but told me that if I were to open up the pedal I would see a BBD chip. He played dumb when confronted with the question about them being manufactured by Biyang and rebranded with Akai graphics. So now I'm torn between just buying the Biyang AD-7 or the Akai.

NiteGoat

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Post by **GodSaveMetal** » 14 Sep 2013, 01:41

Dirk_Hendrik wrote:
roseblood11 wrote:a pt-80 clone, I guess.
Careful with remarks like this. They're similar to calling every dist with clippers in the feedback loop a TS clone.

The setup of compressor, filter, delay line, filter, expander for delay pedals is extremely common. Therefore when the delayline in that setup is replaced from a BBD chip by a PT2399 delay line doesn't automatically make it a PT80 clone.

Upsairs I have a EH DMM with the MN3005's bypassed and replaced by PT's. Does that make it a PT80 clone?

PLEASE!! Mr DIRK it would be a great idea for posting that adapter for replacing MN3005 with PTs!!!! some pictures or scheme to do that adaptation??? It would be fine